Reproduced from:
https://repositorio.ufsc.br/bitstream/handle/123456789/188057/Onde%20está%20o%20organismo%20e-book.pdf?sequence=1
and translated from Portuguese to English via Google Translate

Nelson Vaz
Jorge Mpodozis
João Francisco Botelho
Gustavo Ramos

ONDE ESTÁ O ORGANISMO?
DERIVAS E OUTRAS HISTÓRIAS NA BIOLOGIA E IMUNOLOGIA

ufsc publisher

Where is the organism?
drifts and other histories in biology and in immunology

FEDERAL UNIVERSITY OF SANTA CATARINA

Dean
Alvaro Toubes Prata
Vice Rector
Carlos Alberto Justo da Silva

UFSC EDITOR CEO
Sérgio Luiz Rodrigues Medeiros
editorial board
Maria de Lourdes Alves Borges (President)
Alai Garcia Diniz
Carlos Eduardo Schmidt Chapel
Ione Ribeiro Valle
João Pedro Assumpção Bastos
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UFSC Publisher University
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Nelson Vaz
Jorge Mpodozis
João Francisco
Botelho Gustavo Ramos

Where is the organism?
drifts and other histories in biology and in immunology

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© 2011 UFSC

Publisher Editorial board:
Paulo Roberto da Silva

Cover:
Maria Lúcia Iaczinski

Publishing:
Manuela Soares da Fonseca

Review:
Maria Geralda Soprana Dias

Catalog
(Cataloging in the publication by the University Library of the Federal University of Santa Catarina)

O58           Where is the organism? : drifts and other histories in biology and immunology. Nelson Vaz … [et al.]. – Florianópolis: UFSC  Publisher, 2011. 204 p.

Includes references

1. Biology – Philosophy. 2. Epidemiology. 3. Evolution (Biology).
2. Vaz, Nelson Popini, 1940-

CDU: 57 / 59.01

ISBN 978-85-328-0541-6

This book is under the Creative Commons license, which follows the principle of public access to information. The book can be shared as long as the credits of authorship are attributed. No form of alteration or use for commercial purposes is permitted.

br.creativecommons.org

To naturalist Kay Saalfeld, a rare bird in the corridors of modern biology,  and responsible for the creation of a pleasant school of biology in Santa Catarina.
To all of the Biology of Knowing expeditionaries.

We thank the artist and scientist Hélio Rola, who, through his great sensitivity, honored us with the illustration of the cover of this book.

We want to express our appreciation for the work of professors Dr. Mário Steindel (Graduate Program in Biotechnology, UFSC) and Dr. Sônia Carobrez (Director of the Center for Biological Sciences, UFSC), who were touched by the importance of creating a reflective space in our academic environment and helped to make it possible to hold a scientific meeting at the Center for Biological Sciences at the Federal University of Santa Catarina, which gave rise to this book.

“I suppose that understanding me is not a matter of intelligence but of feeling, getting in touch. Either play, or do not.”
Clarice Lispector

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Presentation

I want to clarify some points that justify my satisfaction in seeing the finalization of the writing of this small book, which brings together modern concepts of Biology and a vision that I developed over the years regarding immunological activity. Fifteen years ago, with Ana Maria Caetano de Faria, I wrote another small book entitled Guia incompleto de Imunobiologia: Imunologia como se o organismo importasse (Incomplete Guide to Immunobiology: Immunology as if the organism mattered) (Belo Horizonte: Coopmed, 1993). I had known Humberto Maturana and his ideas for about ten years, and I tried to include in that book some ideas about the Biology of Knowing. Before that and without even knowing about the existence of Maturana, I published with Francisco Varela a text in which we defended the idea of “operational closure” (enclosure) of immunological activity (VAZ; VARELA, 1978). It was a first approximation to a systemic description of immunology.

The small edition of the Guia incompleto (Incomplete Guide) sold out in a few months. Colleagues and students encouraged me, repeatedly, to reissue it. I decided that I would not do so because I felt it was necessary to support the texts of Immunology over other texts that proposed another revolution, more biological, in the way of seeing living beings.

Through a happy drift of events, but very dependent on the multiple talents and sympathy of Gustavo Ramos, at UFSC, we arrived at this conjunction of texts that make up the current volume, which represents exactly what I foresaw and which, as Gustavo says, it constitutes the rupture of the Gordian knot between defensive immunology and neo-Darwinian biology.

Nelson Monteiro Vaz

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Preface – Questions before answers

Why is it often so painful for us to participate in academic disciplines or formal scientific meetings? This does not seem to be a trivial problem in learning in Biology and, personally, I believe that this situation arises because, day by day, the student is forced to sit in a room to simply have to listen to a teacher to provide detailed answers to questions that were asked. And much of the time, what happens is not that the student has not been able to formulate his own questions, but that he or she felt seduced by personal doubts of a different nature than those accepted by the teacher. From this situation, it turns out that classroom classes and formal scientific meetings often take place in a context that does not favor learning, or even end up being a waste of time for teachers and students interested in enjoying Biology.

Gregory Bateson, one of the most important biology thinkers of the 20^th century, says that “everyone has an epistemology (a way of knowing); otherwise, I wouldn’t know anything. Those who claim to have none have a bad one”. Accepting the relevance of this observation, in an attempt to escape the tedious scenario of the scientific classes, this book was organized based on a careful compilation of transcripts of conversations held at an academic meeting that had the proposal to discuss the questions before the answers.¹ Said otherwise, the material presented in these pages is the result of an interest in reflecting on the way in which we have been placing ourselves as observers and formulating our biological questions, as they are the ones that determine our explanatory paths and the truths that we build.

In this context, during the texts that follow, the reader will be invited to revisit situations, such as the ontogeny of a sea urchin, the diversification of plant species in the Chilean forests, or even the ingestion of proteins from the leaf of a lettuce. Examples that, much more than simple curiosities, refer us explicitly to what is most precious in the natural world: a historical preservation, either in the biological form or in stable immunological processes.

This compilation of essays brings together fundamental reflections on the historical drift of living systems and the immune system. As such, this book – like any foray that makes use of a biological look – essentially deals with organisms and histories. Yes, that seems obvious. Inescapable. And it is at the heart of what is obvious that the texts that follow explain and reaffirm. So, at the same time that we notice the triviality of talking about organisms and histories every time it comes to Biology, we are surprised to realize that the most common way of asking questions in contemporary Biology buries these two concepts. It is because, when presenting an organism that lives crushed between two forces: the first coming from random genetic mutations, and the second arising from the selective pressures of a threatening environment, this official way of raising questions about the natural world creates an organism that is determined and hostage to its genes. So, based on this condition, we talk about information replicators, and pre-formation and adult-centered explanations are accepted, apparently without problems, as shown in the first paragraph of an important book, Darwinian Medicine: “If a DNA strand can code the plans for the adult organism, why are we unable to regenerate a lost finger?” (NESSE; WILLIAMS, 1994); or, yet, statements like the one that appears highlighted in a colored text box in the middle of a recent article in the journal Nature: “It is an intriguing idea that you can peel your genome and reveal your future” (PEARSON, 2008). That is to say, in this explanation centered on the genes, it does not matter the history that happens in the living of the organisms, which, incidentally, there are not even seen as a relevant problem, because they are mere carriers of the information genes and passive responders of cruelty of a natural environment very similar to British society. It seems that the question of “how are organisms reproduced (produced again) each generation” has historically been replaced by a question about “where is the information that is transmitted to the offspring”. One asks for nouns instead of verbs, and with that one answers: “molecules (metaphysics) of life” instead of processes of living. And, with this way of asking, biology arises exaggeratedly focused only on two problems: 1) on the genome of organisms, thus making development unnecessary, the dynamics that would make it possible to explain the dynamic construction of living beings; and 2) in adult living, in which the issues of the struggle for sex and survival can be shown more easily in some specific cases of mammals. Together, these two arguments create a very deep gap between fertilization and the adult individual, already produced and looking for sex and food.

I believe that the scenario described so far, in a still superficial way, makes us realize that we are answering “biological questions that hide organisms and their history”. But how to talk about how a chick is born knowing how to scratch or how the curious bone carapace was formed on the turtles’ back, if not through a systemic and historical explanatory path?

Perhaps the best way to present where our reflections have taken us with this approach to Biology has been put by Bateson (1978): “To say that the organism is a way that genes found to make other genes is the same as saying that birds are a way that nests have found to make other nests”. In this way, it is our conduct as observers, reflecting on our knowledge of a natural world, that determines whether we build a Biology of dry straw or birds. That is why we care so much about “knowing knowing”, even when we are wondering about what is happening with living beings in the natural world, as the Chilean scientist Humberto Maturana would say.

And the same reflections are valid in the case of Immunology, a lymphocyte version of Biology consolidated in the 1950s, which is also concerned only with very particular situations: adult and sick mice. And so, without any attempt to place the lymphocytes located in congruence with the construction of the organism of which the immune system is part, it also hides in the immunologist’s question about Physiology, which, in all other systems, is described before of Pathology. Incidentally, Immunology and Biology are treated together here, as they are pleasant examples of how a way of looking at general Biology has shaped and sustained the experimental and daily practice of a specific discipline. In other words, hidden behind a simple discussion about experimental methods or results in any biological discipline, as in Immunology, there is theoretical support that underlies the way of dealing with more specific problems. And what is dangerous is that this support, in most cases, is implied. There are, therefore, impasses in Immunology that are not resolved with more experiments, but with conceptual discussions contextualized in Biology. And, at the same time, when being tested, published and validated daily, Immunology also reaffirms the biological vision on which it is based.

This extraordinary conceptual knot between Biology and Immunology causes changes in the way of seeing Immunology to imply changes in Biology, and, recursively, serious changes in Immunology can only occur together with the re-discussion of their biological premises.

Our intention, in this space, is not to confront such a long truth in the history of Biology, since different answers to the same questions are not discussed here. In the essays that follow, we only invite the reader to treat Biology and Immunology from different questions, which allow us to understand how we know the natural world in the most general way possible. It is not quixotism; it is for us to enjoy. We want to reflect on how we got here, to show how our questions led us to a way of seeing that blinds us to fundamental aspects of Biology. And we are not talking superficially about the history of Biology, but rather, explicitly, putting history (epigenesis) back into Biology, as a problem to be taken seriously.

If the reader feels seduced by these questions and, finally, ask himself: “where is the organism?”, then the sequence of this material can be configured as an explanatory proposal to questions legitimately formulated by a reader interested in reflecting on scientific doing from a systemic and historical point of view.

It is also necessary to recognize that this meeting, which took place at UFSC and which served as an incentive for the organization of this book, also had as a great triumph the fact of having provided contact between three groups of people, who so pleasantly gravitate towards professors Nelson Vaz, Jorge Mpodozis and Kay Saalfeld; and that, at the same time, also help to illuminate and brighten your reflections. Proof of this is that these same conversations could be expanded in later scientific meetings, as at FeSBE (2006), FioCruz (2007) and Universidad de Chile (2007); and, yet, in so many other less formal moments along the transforming landscapes and horizons of the South American continent.

Last but not least, I would like to make a brief presentation about the main authors of this book, Nelson Vaz and Jorge Mpodozis. However, I do not intend to comment on all the reasons why these thinkers acquired great recognition and prestige in the scientific environment of which they are a part. For this reason, instead of mentioning clichés, such as “a member of the Brazilian Academy of Sciences”, “a founding partner of the Brazilian Society of Immunology”, or “the co-author with Maturana of the Theory of Natural Drift”, I think more appropriate to talk about how they write and speak in a special way. That is, when you read a text by Professor Vaz or Mpodozis, you do not find that impoverished format of a scientific article with sentences shelved in predetermined places. On the contrary, I think that his texts are like tales of Kafka, of those that suddenly end like this, and that, instead of an objective and restrictive conclusion, they leave the reader with an open door, an opportunity to reflect as he can. Finally, to mention Nelson Vaz and Jorge Mpodozis, I prefer to translate myself in the words of Jack Kerouac (1955), one of the main founders of what was later called counterculture:

[…] at that time, they danced through the streets like frantic tops and I dragged myself in the same direction as I have done all my life, always behind people who interest me, because, for me, people are the crazy ones, the ones who they are crazy to live, crazy to speak, crazy to be saved, who want everything at the same time now, those who never yawn and never speak buzzwords, but who burn, burn, burn like fabulous fireworks exploding like constellations in whose boiling center – pop! – you can see a blue and intense glow until everyone aaaaaah!.

References 

• BATESON, P. P. G. How does behavior develop. Perspectives in Ethology, n. 3, p. 55-66, 1978.
• KEROUAC, J. On the road (Pé na estrada). Porto Alegre: L&PM, 2007.
• PEARSON, H. Genetic testing for everyone. Nature, n. 453, p. 570-571, 2008.

Gustavo Campos Ramos,
An expeditionary from the Biology of Knowing.

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CHAPTER 1 – WHERE IS THE ORGANISM?

Chapter 1.1 – The fundamental equation of Biology

Jorge Mpodozis

As some already know, my laboratory was completely destroyed in a fire, so I don’t have many things with me. A notebook is my laboratory right now, and it gives me the freedom to organize my life and my speech in another way. This is, therefore, a conversation that seeks the basic understanding of the questions, that is, I will dedicate myself to build questions and make a reflection around those questions that seem central to me in Biology.

Follow me a little while I draw a scenario. We go to a lagoon, a mangrove. There we find many types of birds: herons, pelicans, seagulls, various types of birds. And there are all these birds living in that place. There is also an eagle flying overhead, because here are the baby birds. This situation is interesting because they are all different, but they are all birds. Are they different or are they the same?

Another thing that arises is that they are not arbitrarily different. Consider the heron, the beak that characterizes it, the position of the eyes on the head, the auditory meatus, its height, the position of its feathers. All of these characteristics are different from those found in the pelican. Where do we find the beak of herons? In the herons. Could we imagine a heron beak placed on a seagull or vice versa? This is remarkable, because there are no such animals with their beaks exchanged. A heron with a seagull or flamingo’s beak has never been seen, because these animals cannot live. Thus, the heron is a unit in each and every one of the characteristics that define it. The same is true of seagulls and pelicans. And they are all birds, all the same. Interesting situation! And I tell you this because there is the question: How does this situation originate?

What does the heron and its beak have to do with? Indeed, when I look at the heron, I imagine its diet and its way of obtaining food. And I can also think of their sexual courtship and their way of building a nest, which are different from the habits of the gull and the pelican, and also of the other, the other and everyone else. That is, when I look at the heron or show them a picture of a heron, I am not simply showing the shape of a heron: I am showing a way of life; a relationship with the environment that is proper, unique, particular and characteristic of this living being and different from any other of those that are there.

Question: do these animals that I see in the lagoon live in the same world? Are they in the same medium? How many lagoons are there? I believe that there is a different one for each animal, even though I see them all together in the same, because the actions of each one of them are sufficiently different. The ways of life that are satisfied in this lagoon are as characteristically different, as are the animals. So, the heron world is the seagull world? In other words, is the world brought up in the heron’s life the world raised by the gull’s life? No. So, how could the world, the adaptation to the world, the lagoon, explain this diversity? Could this happen? Well, that is the problem. We want to know what the question is, and that is the question. These birds to which I refer are adapted (in congruence) with their environment. But what medium are they adapted to, if the medium is unique and different for each of the animals that are there?

They are all birds and, as such, they are all the same. And how did they come to be different? Conservation, change, adaptation, relationship with the environment. Yes, of course, these are the conceptual origins of this problem, they are the phenomena.

Figure 1  Three stages in the life of a heron

There is something else I want to point out. Notice that, in Figure 1A, there is an egg that the heron has just laid, with its shell and its characteristic shape. Suppose the heron is a worker – the mother is diligent – and that this egg lives, follows its life. At some point, it hatches, and I see it converted into a heron chick (Figure 1B). Is what I show in Figure 1A the same as in Figure 1B? Certainly not. And since the weather is good and the world is kind to this chick, there is no fire; this chick grows, becomes large and very complex (Figure 1C). And, eventually, it lays an egg. Is this second egg the same as the original egg (Figure 1A)? No. How interesting this situation is!

What’s going on here? There is a heron egg (Figure 1A); a heron chick (Figure 1B); and an adult heron (Figure 1C) that lays an egret egg and does so in a world where heron eggs are laid – does not lay them anywhere. And the result of this story is another heron. Notice that, in Figure 1C, a heron is represented in its relationship with the world, a bond that is unique; and, in Figure 1B, is the heron chick in its relationship with the world, which is unique; and also, in Figure 1A, there is the heron egg and its encounter with the world, which is unique. The way of relating to the world has changed and the animal has changed too, but the congruence with the circumstances – the adaptation – has never been lost in this story. Evidently, the animal changes, but does not change in any way. This is the case.

What is the question, that is, the classic way of asking yourself? The Darwinian question is “How do living things change to adapt?” Let us consider this questioning. Suppose this adult heron does not yet exist, it has not yet appeared in this story. How would the chick (Figure 1B) change to adapt to this situation (Figure 1C), if it only exists when the adult heron is present? How can it be? The question that interests me is: How do you determine the course of history that these transformations demand? Furthermore, in the case of birds, all birds – the heron, the pelican, the seagull – they all come from an ancestral bird. The same problem exists in Ontogenesis and Phylogenesis.

Thus, during embryonic development, all cells are derived from an ancestor. Figure 1A represents the initial moment: that egg is the zygote, and Figure 1B shows the phase of free life – which I choose as a point of reference, because, in general, in Zoology, we focus on these moments: egg, free-living chick, adult. What happens next does not matter; to this adult heron, depicted in Figure 1C, we give a retirement and hope it dies. After all, she has already laid her eggs, raised her young, done her job and owes nothing to Biology. This is what is said in traditional biology. Several of us, teachers, are in this phase.

Notice that we are fixated on the point where the free life begins (Figure 1B) because it seems to us that there is an important change in the environment. We call development what goes from 1A to 1B; and we call what goes from 1B to 1C, conduct, learning, beginning of conduct in a free life. Does it not seem to you, however, that development and conduct in a free life are of the same nature? These are historical transformations. And I can ask: How do you determine the direction that these transformations are going? And if we consider the transgenerational sequence – what happens from one generation to another – what happens is the same phenomenon. And what we have is what we call phylogenesis.

If I look at the direction of development, I have the initial cell and all the derived cell lines that finally stabilize; and if I analyze them, I can trace a tree (a branch) of cell lines, which looks a lot like a phylogenetic tree. Transformations in ontogenetic and phylogenetic history are of the same nature. We consider all these birds and then we say: lineage of birds. What am I saying when I say this? I am stating that there was an ancestral bird that laid an egg, from which all these birds emerged, in a process of this style: as modifications of that process.

How do you determine the course that follows the story? That is the central question, I believe. The animal is in continuous transformation, a process in which not only changes the animal, but changes the way of being in correspondence with the world, in circumstances in which this correspondence with the world is never interrupted, because when it is broken, the animal dies. The question is: “How is the course of this history of change determined?” And this question is legitimate at any moment in this story. When I want to, I’m pretentious and I say: This is the fundamental equation of Biology.

I say this to surprise students, but this question certainly captures the problem of this conservative transformation. Let’s think: why does a fibroblast divide into two cells that are exactly two fibroblasts? This is not trivial, as any other cell in that fibroblast could come out. In the same way, because we saw another heron coming out of an egg. What is this to preserve? This question is fundamental and, at the same time, neglected, because Biology is more concerned with change than with conserving it. That’s because the Darwinian way of asking is, “How do living things change to adapt?” Thus, the problem lies in change. This is explicit in a lot of places, in the formulation of Synthetic Theory (neo-Darwinism). It is written throughout the genetic-population approach to the evolutionary problem: in the absence of environmental pressure, organisms would not change. Why would they change if they are already well?

In the Darwinian view, changes occur driven by selective pressures. Then, the nature of these evolutionary forces is studied, and what does not change does not matter, according to this approach. And what are these selective pressures? When we see this problem in this way, a pressure is an external agent, a force that pushes a change in a certain direction, which depends on the agent; the direction of the change depends on external agents. The problem focuses on change. The traditional view carries this problem of selective external pressures to all areas. In this paradigm, what we have to explain is the change. But, when analyzing this Figure 1 – the fundamental equation of Biology – it does not seem, however, that this is what I have to explain. Here, I did nothing more than graphically represent biological phenomenology in its most general way, without supposing anything, not even a special mechanism. I look at living beings and see that this is happening. But it comes naturally that what I have to explain is the change? No, it doesn’t. I do not believe that this change (from 1A to 1B, and from 1B to 1C) requires a special explanation. It does not require, because I can assume that change is inherent in living beings. Notice, this is important, that what I have to explain is not change, it is the direction, the direction that the change follows.

I often read that this of selective pressures is a metaphor, and that this “stronger” selectionist view is already abandoned, and that, when we speak of selective pressures, it is as if we were talking about a filter of deleterious mutations … it is, however, the relevant one; the important thing is that when I say that every change requires strength, what I am saying is this: there is an external agent; in this case, it is the means that imposes the direction of change. Could we say, however, that it was, in the heron’s history, the medium that determined the direction of change from the ancestor to the heron? It doesn’t seem to make much sense to me.

Imagine that, at some point, the ancestors of these birds, who today live in the lagoon, arrived and established a way of life in that place, such that everything that has to do with that way of living, that is, all the transformations that occur with the duck and that occur with the heron have to do with this way of life that the animals establish there. In this case, the world they encounter when they arrive at this place is not “the world” independent of their actions, but a world that appears with the living of these beings in this lagoon. If the selection were imposed by the environment, all the animals that live in the lagoon should be similar; and they are not. In other words, even though we see them all in the same lagoon, each bird of these poses, according to its life, a different environment. And, with the preservation of this relationship that is established between each animal with its lagoon or with its world, a different history of transformations emerges. We will insist on this issue. This is what I wanted to do for the time being: a little reflection on the birds of this particular scenario, and, at the same time, about living beings in general.

Organisms as historical systems

What are the organisms? How can I treat them? When we distinguish a living being, what do we distinguish? Let us become anatomists for a moment. I will not pose any complicated problems. Let us be anatomists in the 19^th century, in front of a dissection table where a crocodile is. And, standing beside the table, we have Prof. Cuvier, who had many dissection tables and a different specimen at each. Thus, he did the anatomical study and wrote the text immediately. He wrote, on average, sixty texts simultaneously, because on each table he wrote a text. It was very productive and very busy as well. And do you know how funny that was? He had sixty animals in front of him and then he could ask comparative questions.

So, in this context, here we have the crocodile, and we are going to dissect it; we will rip the brain out of that animal. What do we find in these animals? Organs. And did we find any organs? Where are these organs? Notice that – this is interesting – we cannot find these organs anywhere else, except as they are in the organic composition of the animals of which they are part. The immune system, for example, is not found there. Nor do we come across livers, trying to find a kidney and heart to form an organism.

Unless we are dealing with Frankenstein, this is not the case: finding a collection of organs and assembling them to form an organism. This sounds obvious to us, but interestingly so is the official approach to neo-Darwinian biology, which tries to study the optimization of each small slice of living beings, independently of the others. Organisms and organs are a unit, and this has always been the case. When we talk about living things, we are talking about systems. And there are interesting things going on with them that are worth noting for a moment. Note that we can deal with two types of systems in general. Some of them, like chairs, for example, do not have, as their condition of existence, change. It may be that they change, that they scratch themselves; but change is not part of its systemic constitution. There are, however, other systems that have structural change as part of their constitution. Living systems are of this second type. We know this, because when the dynamics of operations are interrupted, this living being disintegrates. We are aware of this because, if we look at a cell in its cellular realization and treat it as a system of molecules, this is exactly the same thing that Prof. Cuvier when he dissected his crocodile. That is to say, the molecules that allow cellular realization exist only in the cellular context and nowhere else. We didn’t find the loose DNA out there, or the proteins. Where are they? The only protein-forming dynamics and DNA are in cell biochemistry.

This immediately raises the same problem as Prof. Cuvier raised: “Where did living beings come from, where did living beings come from, if living beings require proteins and DNA, whereas these molecules, in turn, require living beings as a condition for their formation?” So, you can say that this is the chicken and egg problem! Yes. This seems like a trivial problem, but it is not.

Let us make an effort to respond to the chicken and egg problem. Who came first? The question is not superfluous, as it is a central question. It doesn’t matter if we are talking about cells or organisms (of ontogenesis or phylogenesis). Cell realization requires, occurs in the systemic interaction of a set of molecular components that only exist in the domain of cell realization.

Figure 1A shows the founding cell: the egg. Then (Figure 1B), the organic performance is the same. It arises from the interaction of a set of organic components that are only present in the context of the existence of this system. It seemed that the question: “How is the direction of change determined?” it was simple to answer. Now we realize that it is more complicated, because we are talking about systems. And living beings, as systems, have this characteristic: they are dynamic and are in continuous structural transformation.

And there is more: these systems are such that the components that form them have as a condition of existence the realization of the system as a whole. Ah, but, if I present the problem like that, in the way that Prof. Cuvier, and then I ask how living things came about, one answer would be: “They were designed”. It is the simplest answer: they were designed. It was Cuvier’s answer.

However, if, as biologists, we prefer another answer, if we want to say that they were not designed, we have to say something else, because we have a problem to solve. Because, of course, the objects that are projected, that is, the components in any artifact, as in a photographic camera, only exist in the context of the camera, depending on the camera they form. If we don’t like the answer to the project, what answer will we give?

I believe that the fundamental equation of Biology also has an answer: it is history. It is like the heron; it is like the process of development. The beak of the heron is in the heron and, moreover, it is in it as a result of its living. Imagine, for example, a man wearing his shoes, perfectly accommodated at his feet, with characteristics that are unique to him – adapted to his circumstances, I would say. Doesn’t it seem obvious that this harmony, between the shoes and the feet that put them on, arises, spontaneously, as a result of their particular history? Or it would also be necessary to suppose that, in order to obtain them in this way, that gentleman had to go to a factory and order something around a thousand random variations of pairs of shoes and try them on until he got one that was less uncomfortable; so, from that way on, he would ask the manufacturer to make a thousand more small one-off variations, and thus, after many attempts, he would finally get a shoe that was adapted to his feet? When we know the history, the way of living, there is no need for any special mechanism to explain this situation.

And something interesting happens. It occurs first that this system is dynamic, that is, it is in continuous structural exchange. If a change stops its structural dynamics, it disintegrates. It is changing continuously; it changes, like this, like a river. If we see a cell – what is this cell? What do we see? A molecular system. Where are the molecules? How long have they been in the cell? What does the cell consist of? It consists of a network of molecular transformations, because the molecules are changing continuously. We can have a complete replacement of atomic and molecular components in a time interval that is not large. But if we stop the dynamics, the system is over.

The same goes for the organism as a cellular system. The cells have a molecular existence, and there is a continuous replacement of molecular components. This gentleman is breathing, and if I don’t let him breathe, he dies. Thus, continuous structural transformation is a condition of existence. Interestingly, however, the structure that transforms has an identity. This gentleman remains. Furthermore, it is said that he has the same identity that he had when he was an egg, a zygote. Note that this subject is interesting. The heron we were talking about is the same since it was born, since it is there, in the egg (Figure 1A). The identity remains under circumstances in which the dynamic is continually transforming the structure.

Does it drive us away or bring us closer to the answer to our problem? From our question: “How is the course of change determined?”, I think it brings us closer. In addition, there is another element that I think is important. In addition to living systems, do we know of other systems like this, whose identity is preserved under continuous structural transformation? I believe so: a river. Is a river metaphysical, or does it belong to the transformations of the physical world? Evidently, it belongs to the physical world. It is a flow, a continuous flow. This is a very thought-out problem, very philosophical. The river is a pure relationship between things, it is not a thing.

Likewise, a hurricane is a relationship between things, between molecules in the air. A whirlpool is a relationship between water molecules. A living being is a relationship between the metabolism molecules. It is a relational object. This does not make him less object, or less physically operational, does not make him less operational; on the contrary, it is a flow. Living beings are flows whose identity comes from the relationship between the components that form them. Evidently, we say that this gentleman has had the same liver throughout his life, and the same neurons, etc. Sure, but no molecule in those neurons is the same molecule that was there three weeks ago.

This is very interesting and is a fundamental aspect of living. That is why this way of thinking about living beings as static objects, which change when they are forced to change, is a poor way of thinking, as it captures little of the constitutive dynamics of living beings. And I say this without any presumption; I comment this with regret. Treating living beings as static objects, which change when pushed by an external force, is like squaring the circle: taking a circle and, through geometric transformations, transforming it into a square. The square and the circle are constitutively different. These are different logical situations. Living beings obey this logic of continuous transformation, as they are relational objects, which are in history in this way.

And given that this is so, there is another relevant thing that I would like to emphasize about the systemic existence of living beings. As they are in continuous structural change, the organism’s relationship with the world is the reference for its existence, because if that relationship is interrupted, the organism disintegrates. And if this occurs, the organic components disintegrate, because the condition of existence, the space of existence of the organic components is the totality. These components exist while forming a totality. And that totality exists while maintaining its structural correspondence with the world.

It may seem that I want to force you into some confusion, but it is not so, or rather, yes. This is because I speak of fluidity. In the history of Biology, this has been pointed out, many times, by many different authors, by physiologists, and also by comparative anatomists, and, rather, by the “vitalist” thinkers of Antiquity. Everyone touched on that same point, in this coupling of the conditions of existence, of correspondence with the world, as in the case of the heron that, in all moments of its history, was in correspondence with the world. A conservation of the correspondence relationship with the world, which is a condition for the existence of this system as a whole. And the existence of this system as a whole is a condition of existence for the organic components. And since this is an intrinsically dynamic situation, because this is a situation of historical, dynamic interaction, this relationship will inevitably change during history. Thus, either the organism is transformed following correspondence with the world, or it disintegrates.

But what is this transformation of the organism? Where does it come from? What becomes in the organism? It is the structure that changes, the relationships between the components change. Say, what changes is the way in which these components make this system. We therefore speak of structural plasticity. There are many ways in which this system can operate, as there are many ways in which these components can satisfy the conditions of existence of that system. And it is the story of what will happen, because it will follow a story, as shown in Figure 1A, B and C. It is inevitable that this will be transformed. The transformation will be such that the structure (the organic composition) will change so that the animal’s relationship with the world is satisfied, or else the organism disintegrates.

So, it is expected here that a structural transformation will take place, which may be short or long, last long or last short, may be intense or light, but it will result from the satisfaction of this correspondence relationship with the world. So that, in the stories of transformations, this relationship can be preserved while the structure changes. This is what happens, for example, to the heron (Figure 1A, B, C), and also what happens to cells in development.

Think of the woodcutting bird (Rynchops niger), which has the longest lower beak, and fishes flying close to the surface with its beak cutting through the water. And what does this have to do with? How to catch the fish in the water. Where did this come from? From a historical process. This is the being of the skid. What made it emerge as such was its history, because, as it approaches this particular mode of pecking, which is preserved from generation to generation, all the plasticity that this animal has changes around the conservation of this way of achieving food. And, as a result of this particular history of encounter with the environment, the beak of the skid is modified. And this is the story of how the beak of the heron and the beak of the duck are transformed as well, which are transformed in a way that depends on the relationship established between the beak and the world.

It would seem that the “niche” has entered the body. One might think so, but our goal now is to understand the process of organic transformation and, to do this, this conceptual separation is important. The medium “entered” the organism, not as a “medium”, certainly. See, let’s take a chick that is in the egg and do a nasty thing with it: we give it an injection of curare, which inhibits neuromuscular synapses. And this chick continues its development, but still. The result that we will see, when peeling the egg at the end of development, is a completely deformed chick. It has the longest beak; the wings are not formed. The movement of the chick inside the egg is part of the inheritance. It is similar to a fish whose larva has a free life and changes into an adult moving in the marine environment, in a context in which its actions participate in determining the transformations it undergoes. The chick also has a life like this – mobile – but it takes place inside the egg. I can consider the chick not as an embryo, but as a larva, because its actions inside the egg are part of its development. In the case of fish only, this occurs in the ocean; and with the other it occurs inside the egg. Have you already incorporated the medium? This phenomenon can be mentioned in this way, but the interesting thing is to understand the process behind it. I mean, this is an active process. I think it is central to understand this condition, this systemic binding between the system, its components and its condition of systemic existence. This is essential to understand how the course that follows this story is determined.

Structural determinism: a minimum principle with maximum consequences

There is also another concept that I consider very relevant when we are in this systemic view of living beings, illustrated in Figure 2. We speak of a first period of development, followed by a period in free life, in which the conduct of the living being occurs. Watch out for a goldfish, which has a tail that can be referred to as an effector. When the tail moves, the fish moves; can move forward or backward. The fish has a mouth, with threatening teeth, and has two types of sensory organs: one that fits squares and triggers approach movements on the tail; another that fits triangles and allows movements to move away from the tail. The environment in which this fish lives contains a number of different objects: some that are or contain triangles; others that are or contain squares. There are still others that are not, nor do they contain triangles and squares. All of this, I say as an observer, included in this experience.

This fish has a nervous system with many nodes, and has a brain attached to the movement of its tail. According to the triggered receiver, it approaches objects and eats them, or moves away. Other objects, which neither are nor contain triangles or squares, are not in the cognitive domain of fish. They don’t exist for him. Furthermore, it does not distinguish objects that are triangles from those that contain triangles; there is no way to distinguish them, because they are equivalent in the context of their structure.

Figure 2  A fish, its nervous system, its sensors and effectors

If we were inside this fish, what could we say about the world where we are? We would only say that there are objects that we approach and others that we move away from. Only that. But does approaching or moving away from these objects depend on them, or does it depend on the animal? Certainly, it depends on the encounter, but what results from that encounter, that is, approaching or moving away from objects, underlies the animal’s structure. In this case, what happens to a system depends on how it is done at that moment. There are no magic wands, nor external selection pressure guiding the course of their transformations. That is to say, this system only interacts with what its structure identifies as possible, and the changes that happen are those that its structure allows. We can also say that the nervous system of this fish (Figure 2) operates at all times, determined by its structure at that moment and through the play of the properties of its components. After all, could we manage this animal, this fish, from the outside?

Suppose a phone (traditional, wired) and that we are inside the phone, and then we hear tic-tic-tic-tic tic, and tic-tic, and tic-tic-tic-tic … Question: can we distinguish from who is the finger that is dialing the phone? We have no way of knowing that. Likewise, the fish cannot interact with objects for which it has no receptors. And when you interact with an object, you can only know that there was an interaction of a certain type and not the object that triggered it. These receptors that the fish exhibits, however, also depend on its structure and history.

When I speak of a system, the agents that disturb it, those arrows that fall on the system cannot determine the structural transformation that it will undergo. I can’t tell if what disturbed him was a finger, or something else, I can’t help it. The structural transformation, which arises as a result of an interaction, depends on the structure of the organism, i.e., the way he is enmeshed at that moment. Can we then force a system to change? Or specify the direction in which it will change? Does this direction depend on the disturbing agent? No, it is subordinate to the structure. In this context, it does not seem appropriate to refer to the organism’s relationship with its environment in terms of stimuli and responses, external selective pressures, or even inputs and outputs. How can we then answer the question about how animals change to adapt to the environment? Can this happen? Cannot. This operation of a system, in this case, the organism, according to the articulation of its structure, is what we define as structural determinism (MATURANA; MPODOZIS, 1992, 2000).

Note, however, that it is curious: the environment cannot direct the changes in the organism, but, at the same time, the organism cannot exist without establishing relations of congruence with its environment. This is interesting, because the heron is complementary to making the heron in the world. And that also presupposes the lagoon. This heron without a lagoon, without fish, does not exist. And yet, in the epistemological sense, this heron is completely blind to the world where it is, because it has not changed to reach the lagoon. She was never able to look at the lagoon with eyes independent of herself. As if the heron thought: I have to do this to adapt to those fish! Thus, the fish that heron eats appear in her encounter with this lagoon. They weren’t there before, they come up with it. Nobody, nothing forced this heron to adapt to this situation. It is not external agents that drive this transformation. Finally, it should be noted that, as observers, we describe the heron and the other birds living in the same lagoon; however, the niche that each establishes is unique and underlies its structure.

Realize that in this representation shown in Figure 3, there is the living system (A), its organic composition (B) (that is, A + B make up the animal), and also its relationship with the world (C). Insofar as the preservation of this organism / world relationship is a condition of existence for the organism – because, if it is lost, the animal dies – this relationship (Figure 3C) becomes a reference for changing the structure; that is, its formation and conservation will be references and guides for the transformation of the structure in history. This organism / world relationship does not depend, however, on the world, but on the living being in its encounter with the world. The heron gives rise to the lagoon where it is placed. Interesting that it was not a heron when it arrived there, but, once it became a heron, we can take it away and put it in a place where there was never a heron before, and suddenly, the lagoon and heron appear. With her.

Figure 3  The organism / world relationship.

Different description domains

On the contrary, I am saying: everything on the contrary. And there is another thing, the last thing I say, for the moment, for you to enjoy – it is not for you to suffer that I say this, it is for you to enjoy. Something that can also be deduced from the same things and that is also central to understanding the fish represented in Figure 2. This animal dies, its neurons die. So can the tail muscle swim? The fish certainly nothing, but the muscle nothing? Does the muscle in our legs walk? No, he doesn’t walk; it just shortens or lengthens, no more. Walking appears in the encounter of the animal that has this muscle, with the world where that animal is. In such a way, if I remove this muscle from that position in the fish’s organism and implant it in another position, the behavior changes. That is, the effect of its contraction is modified; but on what effect does it depend? of muscle? No, it is subject to the system that this muscle is in. Furthermore, it depends on the system’s interaction with the world. This is understood by the following joke: I take a man by the armpits, lift him off the ground with a rubber band and tell him to walk. He walks? No, he does not walk, although his muscles shorten and lengthen as if walking. And if I registered, at that moment, the neurons that control the rhythmic movements of the limbs, I would obtain a record identical to what I would obtain with this man walking. If I were looking at the neurons, I couldn’t tell if it was walking or not. Where’s the walk? It is not in the neurons, it is not in the muscles, it is not even in the movement: it is in the encounter of the animal with the world. The conduct – walking, knowing – belongs to the organism / world relational scope (Figure 3C). In turn, physiology is concerned with structural dynamics, internal to the system (Figure 3B). They are different, separate things. The only situation that engages these two different dynamics is the systemic condition that we mentioned earlier. The realization of the organism / world relationship is a condition for the existence of this system, as a unit, which, in turn, is a condition for the existence of the components that make it up. This is a systemic relationship; it is not designed on the components; it does not require any special components. It is constitutive, it exists by itself, so that we do not have to search in one scope for what belongs to another, because they are different, separate domains of description.

So, considering that these two domains – that of conduct (Figure 3C) and that of physiology (Figure 3B) – are distinct, separate, what exists inside the brain of this fish? What are there are just neurons, action potentials, synaptic relationships. And where are the reasoning, your memories? Interestingly, they are not here, in the brain. Same as before: the movement is not in the muscles. Do you know what I’m saying? I am saying that thoughts, memory, or walking are not something that happens in physiology (Figure 3B); but in the domain of the organism’s interactions with its environment (Figure 3C). Thinking is doing, it is conduct. It is not a process of the nervous system, in the same way that walking is a doing, which exists in the animal’s relationship with the world and not a muscular process.

This approach that contemplates the systemic condition of a living being avoids, frees us from these vitalist concepts: the vital force, consciousness, genes, components that contain the properties of the entire system. Could this happen? In the representation shown in Figure 1, does the egg contain the chick? I do not think so. So, do genes carry information? Can we even say that everything that resulted in this historical process is contained in the genes? This would violate this systemic and historical constitutive condition of living. It corresponds to suppose that what belongs to the system belongs to a component that contains the properties of the system. And that cannot happen. If there were a system that has such components that contain the properties of the totality, we would be talking about something else, not a system, because a system is built according to this mechanistic dynamic. It is, therefore, determined by its structure and all the things we have just examined take place. To suppose that the genes contain the adult chick is like assuming that the muscles contain walking, under the circumstance that this action results from the interaction of the animal, which has muscles, with the world. If this muscle participates in the organic dynamics in a way specified by the animal’s particular organic architecture, then, when that muscle contracts and relaxes, the animal will walk if it is supported on the ground. Right? So, having said that, does the idea that genes contain the animal in formation make sense? I don’t think so, because the development, the epigenetic emergence of structures is a systemic situation.

In Biology, the history of Morganian mutations is well known and, as in a fruit fly (Drosophila melanogaster), which undergoes a certain mutation in the genome, the paws disappear; undergoes another mutation and the wings are changed; another, and the antennas disappear. But these same phenotypic changes can be produced without genetic changes taking place, merely by changing the conditions of development: the phenocopies. If we look at the phenomenon of phenocopies, we will notice that changes in development conditions result in a regular, systematic and reproducible way in occasional changes in the phenotype. If we made this observation before studying the Morganian mutations, we would have a genetic-epigenetic, in which genes would be in second place, right? I say this because what allows us to propose that there is a relationship between genes and the development program is that, if we change the genes, we have occasional changes in the phenotype, sometimes. Right? The same happens when we change the conditions of development: we have occasional changes in the phenotype, which are the same that we obtain by modifying the genes. So, is the development process contained in the genes? Is it an interesting explanatory path, one that deals with genetic information, responsible for the inheritance and shape of living beings? Let us reflect. What does this concept of information mean? What do you mean in operational terms? When we say that there is information, what do we mean by that?

I have here in my hand a key to the hotel room I am staying in. She opens the lock on the room. I put another key in, and the lock won’t open. I open the lock, examine it and say, “Ah, that key has the information to open the lock!” Would I say that? No, because when I say that, I am not saying anything useful in operational terms. On the other hand, I declare: “Look, what happens is that the key has this characteristic anatomy that corresponds to the shape of the lock, such that when the two are brought into contact, a movement occurs that cannot occur otherwise”. Then, I don’t need the notion of information. In other words, this metaphor of information is not operational, it is metaphysical, as it does not refer to processes. And, if I know the process, I don’t need the notion of information.

The other day, in the other hotel I was in, the “key” was electronic: a card that was placed in a slot and, ready, the lock was opened. So, now we say there was information on that card? There was a type of structural correspondence that, for us, is not evident. When this structural complementarity is not evident, then we say that there is information. We say that the card contains, in code, information that opens the door. Why do we say that in relation to the magnetic card and not in relation to the key? We put it in these terms because, in the case of the key, the mechanism of structural complementarity is evident, but when I insert the card into the lock slot, what is happening is not evident to our eyes.

Is there information captured in this biological system? What we have is a situation of structural correspondence. Whenever we encounter a situation like this in a system and we do not know what is the structural matrix that allows this complementarity, the notion of information seems adequate. But it is metaphorical, it has no operational value. It is a concept that does not belong to the field of Biology.

We ask, for example, what is the neural code? What are you asking with that? What do you want to know? Of course, when there is a situation of structural complementarity, we can speak of codes. But the question is: How did this situation originate? This is the problem, not that there is a structural correspondence that allows us to refer to it, metaphorically, in terms of codes.

In this way, we can exemplify the situation of DNA and proteins. When we say that DNA encodes proteins, what are we saying? We are pronouncing: “The key opens the lock”. However, if I isolate the DNA and place it in a flask, is something coding? When does this become a code? When is this key that I have in my hand a code for the lock? The moment it is inserted in a particular structural matrix, because if I put it in another lock, there is no information. It appears the moment I insert the key into the lock that can be opened. So, where is the importance: in the component that I say “encoder” – because this is often given preferential attention – or the structural matrix in which that component operates with such? After all, is it possible to separate DNA from all protein, metabolic machinery of post-transcriptional maturation that determines the effect on the metabolic set that has DNA? When we speak modernly of a gene, we no longer speak of a hereditary particle; that is, a gene is a kind of molecular process, it has nothing to do with particular molecules lined up on chromosomes. What I mean is that “information” is a metaphor that we use when we don’t know what the matrix of operations is under conditions that we use when we want to refer to situations of structural complementarity – and we don’t know what is the structural matrix under which this complementary relationship occurs. Thus, I want to claim here, in this circumstance, the right to a biology free from the concept of information.

References

• MATURANA, H. R.; MPODOZIS, J. Origen de las especies por medio de la deriva natural. O la diversificación de los lineajes a través de la conservación y cambio de los fenótipos ontogênicos. Santiago: Museo de Historia Natural, 1992.
• MATURANA, H. R.; MPODOZIS, J. The origin of species by means of natural drift, Revista Chilena de Historia Natural, n. 73, p. 261-310, 2000.

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Chapter 1.2 – Ontogenesis

Jorge Mpodozis

On this occasion, I intend to expand some themes related to this “fundamental equation of Biology”, which has to do with the process of ontogenesis. This is a situation in the style represented in Figure 1, which, say, is an “amniotic-centrist”² view of the problem, in which we have: the egg, the chick in free life and the adult who lays an egg. The animal, inside the egg, breaks the shell; the little bird is born, which grows into an adult, sings, sings a lot, and ends up laying an egg.

We see this cycle repeat itself indefinitely. Aristotle said something interesting: “Reproduction fulfills the eternalization of the finite”. So, stop it, in reproduction, there can be nothing new: reproduction is fixist. The reproductive process is necessary and makes what is finite eternal, that is, this way of seeing does not believe in change, there is nothing new; this is an eternal process.

Today we know that this is not necessarily so, but it is interesting that this situation is always repeated, and the course that history follows is the same, generation after generation. And the question is: How do you repeat it? How can history keep this course? Could she take other paths? Are there other directions, sequences of possible changes? What makes this situation always the same? These questions are not trivial.

First of all, before we deal with this issue of reproduction, I would like to recall some cases of sterile hybrid animals, such as the mule. These are interesting examples to keep in mind, because they show that reproduction is not constitutive of living; there are living beings that do not reproduce. Yes, they can do it, because there are living beings that reproduce as part of their lineages; and that is the way of life we want to examine now, in which the way of reproducing is part of the way of life of the lineage.

Reproduction as a systemic process

Reproduction essentially involves a fracture in all cases: in particular, vegetative reproduction³ is directly a fracture; with regard to sexual reproduction, there is a fracture and then the fusion of fragments. It is not any fracture, because not every way to divide a living being results in its reproduction. Removing an arm from a human being is a mutilation, not a reproduction. However, some cuts in certain types of worms can produce two individuals, as in planarians. We have this amnioto-centrist view of animal reproduction and we are used to thinking about animals that have sexual reproduction and a developmental process; but, in many animals, vegetative reproduction is common. When we cut a planaria in two, in the proper way, two planarians appear.

If we take a cell and cut it, do two cells appear? Not necessarily. There is a certain way to cut, a certain dividing plane, which results in cell division. The division must be such that the organization of the parent system can continue to take place in the fragments resulting from that division. That is to say: if there is reproduction, there is conservation of the parent’s organization in the fracture. What is required in the case of dividing a cell? There are many things in the study of cell reproduction: meiosis, mitosis, and, of course, DNA reproduction, DNA transmission and modification.

DNA molecules are concentrated in certain points of the cell, whereas many other molecules are widely distributed. In any case, the division is always that of a functioning cell, whose metabolism is necessary. Likewise, the union of fragments, in the case of sexual reproduction – fertilization – is always an encounter of two cellular dynamics, not of particular components. Of course, there is another situation: I can remove the nucleus from a cell, and it dies, but not immediately. Experiments of this nature with acetabular algae are exemplified in many books. Organisms of the species Acetabularia mediterrânea, despite being made up of a single cell, are quite large and reach up to almost 2 cm in length. Thus, its nucleus can be removed, and the cell remains alive for many months. How long do you survive? Well, as long as the cell contains the enzymes and proteins capable of continuing to carry it out. These are experiments carried out at the beginning of the 20^th century (HÄMMERLING, 1934) and which have to do with the conservation of the metabolic network. There is nothing special about this, as enzymes and proteins are large molecules that degrade easily and thus have to be replaced with new copies of the same molecules. The molds in which they are made can be very active and, at the same time, stable. Were the molds unstable, the resulting protein network and the entire metabolism would be unstable. So, the type of mold that we would like to see is a stable one.

I am saying that, if I have nucleic acids, I can have a metabolism that can be stable and, moreover, that can be inheritable, because if I inherit the nuclear material, I will inherit a protein network that specifies a particular metabolic dynamic. But that does not make DNA responsible for inheritance. Of course, DNA participates in reproduction, but so do all other cellular components. If we left all mitochondria on one side, even if the genes reproduced, there would be no cell division. Strains are stable as a result of metabolic stability. The protein network that makes up the metabolism is conserved; and DNA is part of the transgenerational conservation of that network.

When we consider a cell, we see an intricate set of reactions, as in these metabolic maps. A cell of Escherichia coli is represented as a large drawing full of nodes and arrows that go to and depart from them. All that this illustrates is secondary metabolism, it doesn’t even show protein synthesis or other things, but just the transformation of metabolites in a cell. But is this a cell? Does this map capture the heart of cellularity?

There, all the architectural relationships of the cell are omitted, which is much more interesting in its three-dimensional structure, unique, specific, because each of these components remains in a particular spatial relationship with the other components. The position of each of these components is determined in the space of relationships with the others, and the metabolic network is defined as a consequence of the metabolism itself. The cell map is not the cell, nor is it close to being.

Suppose I take all these enzymes and put them in a test tube, with all the cofactors and the things necessary for metabolism. What am I going to have there? I won’t have a cell. It would be possible to manufacture a cell. Yes. To achieve this, however, it is necessary to know how to have all these components in an architecturally precise and particular spatial matrix. A spatial matrix that also reproduces with the reproduction of the components. In this context, I do not believe that we can see the problem of cell reproduction as a mere problem of reproducing genetic information. This would be such an incomplete approach that it would no longer be relevant to the organism.

Cellular reproduction requires not only the duplication and division of cellular components, but also assumes that these cells retain the relational positions of this entire structural matrix through which metabolism takes place. Which of the components that are there participate in the cell reproduction process? In reality, all of them. Furthermore, they do not take part as separate components. In reality, they could not participate separately, because we are dealing with systems; and their properties, as we discussed earlier, are not represented in the properties of their components. When the cell reproduces, a system is reproducing, that is, a web of relationships, a matrix of relationships between components.

The separation of organelles, integrins, cytoskeleton and nucleic acids is not random during the cell division process. It may have been in the past, but, while there was no way to stabilize all of this transgenerationally, there were no lineages of living beings. Primitive organisms, however, made reproduction part of their way of life, and then lineages were formed. Everything else depended on it, and in this case, we are talking about a living being endowed with a transgenerational stability of its organization.

Well, this is the essential situation with regard to reproduction: it occurs with conservation of the organization. But let us return to the case of inheritance, which is the structural similarity between the descendant and the ancestor. Inheritance is a consequence of reproduction. Still in Figure 1, when do we say that the heron reproduces? When can I say: this is my son, he has my nose, his mother’s eyes. When can I say this? We certainly cannot say that when we look at the embryo. We note the similarities when we compare organisms at the same stage of the reproductive cycle. So, inheritance is the result of this development process. What we call an inheritance – “This boy inherited his grandfather’s nose!” – arises when we compare similar moments in the cycle, so that it is this relationship that arises as a consequence of an epigenetic history.⁴ I mean, ontogenies are similar and result in structural achievements similar enough for us to say that, in some of the characteristics of this phenotype, there is an association or similarity between the ancestor and the descendant, but it also looks like the ancestor of another animal: it has the eyes of the mother, the nose of the father.

The interesting question is, therefore, to establish: How is the course that follows this development history determined? It is a difficult question to answer in mechanistic terms. It would seem that it requires a teleological response, because we often confuse processes with their results. Interestingly, it is the same with the theme of adaptation. For example, it is said that the ultrasound that the bat emits is tocapture insects in the dark of the night. Of course, because I don’t see bats emitting ultrasound in contexts other than capturing nocturnal insects. It is thought like this: bats emit ultrasounds during the night and capture insects that are part of their diet; this explains the characteristics of the bat that differentiate it from other animals. Thus, it is quickly concluded: such ultrasound exists to capture nocturnal insects. There is a great temptation to think like that, in a finalist way, as if the organism were forming a heart to pump blood and end the perfusion of tissues.

It is as if, you see, as if the result intervened in the direction of the process. Here’s the bat emitting ultrasound. Who else issues them? And, see, everything that happened to the bat is wonderful. There are bats in which the face has been deformed to make the ears larger; others where the face has become smaller to increase the interaural distance; total modifications of the rostrum to make the animal capable of emitting ultrasound. There are many changes in the auditory structure of the middle brain and the anterior brain associated with the entire process of making distinctions between interaural differences. It’s unique, the bat’s brain.

There is, therefore, a tendency to say: the result is part of what is happening. Changes start from here to get there. And, then, we realize that this is teleological, it is a finalist idea that puts us out of systemic, biological operability. Anyway, invoking the future to explain the past is not part of biology. But, then, how to explain it? It is no less metaphysical to say that there is a special component (DNA) in the egg that contains and explains how we arrived at adult form. This is, however, the answer of official Biology.

Notice how elegant the form – epigenetic – in which Aristotle explained these things, because there is this other option, which Aristotle denied: pre-formationism, the idea of thinking that the animal is already whole, in miniature there at the beginning. Where do you think the term “development” (development, unfolding) comes from? It is a transformist term. Supposes that there is a miniaturized bug in the egg, which grows and develops. The term “evolution” means the same thing. It is like a blooming; it is like the flower that is on the bud and opens.

Aristotle denied this, because he had observed the development of the chick, noting that the heart appears first and then the brain appears; subsequently, the sensory organs, the liver and the digestive system are formed. The organs are not contained in the egg, but they appear in a process. And we call this process of epigenesis, which means the following: that the being is not contained in the egg, but that it appears historically. Very elegant. It appears, it is not preformed. In fact, it emerges in history. But why does history take this course and not another? If I don’t have a notochord, I can’t have a neural tube; if I don’t have a neural tube, I can’t have a brain; if I don’t have a brain, this little bird doesn’t learn to sing; if he doesn’t sing, he doesn’t find a sexual partner and, without that encounter, he doesn’t produce eggs. Let’s look at the story upside down: singing requires the brain, which requires the notochord, which forms in the egg, and the egg requires the bird. It’s a cycle. The egg is a condition of the bird’s existence, which, in turn, is a condition of the egg’s existence. How does this come about? Why is this the direction and not the other?

What did Aristotle say about this? I said something very interesting. Here is the egg, which he calls “menstrual clay”, something that the female produces, which is feminine and disorganized. The sperm enters there, and organizes the menstrual clay, gives it organization, it is the formal cause; give it the shape, inform it. It gives shape to that menstrual tissue. There is something in the sperm that has the ability to transform that egg and set this process in motion. Then, at the time of reproduction, what was chaos takes on a form that is activated by this formal agent.

It means that there is an agent, or a component here, that has the property of directing the development process. Does this seem familiar to you in any way? What is this modernly called? The agent that gives Aristotle’s form is now called genetic information. It means that we are now saying what Aristotle said more than two thousand years ago. There is a component that has the property of changing the other components without changing itself; furthermore, because it does not change when it is triggered. I mean, it is a more sophisticated way of talking about a formal cause; it is contained in a certain way, not intact, but potentially in that genetic material, in this DNA, considered as an informing agent. And in biology, we don’t like pre-formationism, the ideas of “miniaturized embryos” seem ridiculous. But this idea, this informing agent, is not much different. The historical nature of this situation is being lost here. What is usually seen with the development program approach is that there is a genetic state-1, which determines a phenotypic state-1, and that genetic state changes to a second, which, in turn, determines a phenotypic state-2 ; and, then, this phenotypic succession follows a sequence and an unfolding of a genetic program, which contains the next instant in each instant. The question that is not asked is: Why is this directly directed to the final state? Or, why does this follow this sequence? In other words, if development were merely a transit to adulthood, then we could form the liver, heart and brain, separately, and, at the last moment, put all these things together and have an organism; but that is not the case. It does not occur precisely because the process is not directed by an external agent for a specific purpose, in this case the adult organism.

The notochord induces, according to classical embryology, the invagination of the ectodermal tissue from which the neural tube will arise. If there is no notochord, there is no neural tube. If this tissue interaction does not occur, this result does not occur.

This is a systemic situation. And as such, what happens to each of the components depends on the relationship they have with the other components of the network. A change in one of them will be spurious and will have a deleterious consequence if it occurs regardless of changes in the entire systemic context.

I am going to give you a couple of examples from Developmental Biology. Suppose I take an amphibian egg, when it is in the two-cell stage, and kill one, but leave it attached to the surviving cell; an embryo appears that is half an amphibian. If, however, I completely separate the two cells, two normal amphibians appear. This is because in this interaction between the two cells, the survivor, which remains attached to the dead cell, looks at the world through contact with the membrane of the other cell. So, the dynamic of transformation that remains in that cell depends on the interaction with the other.

Mammalian embryos, upon reaching the 16-cell stage, compact. And when they do, they separate the internal from the external environment (or rather, the extracellular environment is created); thereafter, the embryo begins to behave like an organism. But that it compacts like a morula is decisive for the development that follows, because, then, the external cellular layers are formed, and an internal tissue mass is constituted; from the external, the embryonic attachments are structured; from the internal, the embryo is formed. In fact, there is a similar segmentation in all amniotics, a type of segmentation that is typical of them. However, the formation of a morula depends on the physicochemical conditions of the environment, on the interactions of this embryo with the world where it is; the physicochemical properties of the egg and uterus.

Do you know animals that lay their eggs anywhere? Where do bugs lay their eggs? A bird puts them in a nest similar to the one it left. Building a nest takes a lot of work. Yes, because the condition of the beginning of this story, the niche in which the egg rests at the beginning of this story is part of the determination of the inheritance process. This egg cannot be placed in any uterus: it has to be placed in a particular place. Thus, if a human egg is placed where humans leave, then a human being will result from this story; if it were placed elsewhere, for example, a fertilized human egg in a gorilla’s womb, it would probably result in something else. In this case, the place where the egg is placed is part of the human heritage, as a consequence of the development process, both in the human case, as in the case of birds or any other animal.

Another interesting situation is the development of amphibian eggs. Their eggs are anisotropic, that is, they have a different concentration of proteins in their two poles. Among what is distributed like this, unevenly, are transcription factors, which regulate the differential expression of the genome while the egg is dividing. But how is it divided? It does not do it arbitrarily, because the place where the sperm penetrates the equatorial region of the egg determines the cranio-caudal and dorsoventral axis of the amniotics. Thus, in the place where the sperm penetrates, a different movement begins in the cytoplasm that activates all development, in addition to determining the axis of the embryo. The sperm can be inserted anywhere in the equatorial zone, but the point where it penetrates becomes definitive, because that place determines the direction that the whole development process will take.

In fact, in the end, this process deals with a DNA that is totipotent, and capable of expressing any protein network, in any of the cells of the numerous cell types that will appear there. And what is needed is to differentiate the cytoplasm so that the readings made from this DNA are differentiated, according to the differentiation that was carried out on these transcription factors in the cytoplasm at an early stage of development. In the following moments, the cellular interactions that go through the history of development will contribute to differentiate the network from the transcription factors that determine the genetic network that mobilizes a particular protein and enzymatic machinery in different cell types.

And does DNA participate in this? Evidently, and we have seen how it takes part. In effect, the cytoplasm, the historical condition, and the relational one participate. Most relevant is that this history of ontogenesis is a “drift”. And to say this represents that each instant is the starting point for the next instant. That is, it does not follow a predetermined direction. We mention “drift”, alluding to the spontaneity of a drunken boat, at sea, without a helmsman or navigation chart to guide you to a destination. The course is built moment by moment, as a result of structural determinism and the interactions between the system and the world in which it is taking place at the moment. As a consequence, we cannot say that a drifting boat approaches or departs from somewhere, because that point of arrival has never acted as a reference for the circumstances that led to it.

I want to give you an example that you like, so that you can really appreciate what I am putting now. How is asymmetry determined in embryos of all chordates? Have you ever heard of the phylotypical stage of chord embryos? There, there is the embryo with branchial arches, somites, the segmental organization, the neural tube and the tail. It is full of asymmetries: the heart and spleen are positioned to one side; the liver, to the right; the intestinal loops are turned in a certain way; the nervous system has many asymmetries that develop in a fantastic way. In an early stage of development, this embryo has, on its tail, a ciliated epithelium, which develops initially. With their beat, which is always in the same direction, these lashes generate an upward liquid current, which is lateralized, is more to the left than to the right. And in this stream, many transcription factors and peptides are flowing; and then different states are created on both sides of the embryo. A small motor, a pump, which differentially irrigates the left side of the embryo, and that carries secretions that have different effects on development. In effect, this can be changed, resulting in animals with the rightmost heart, and so on.

Yes, of course there are genes, and they have to do with the expression of the ciliated epithelium, and everything. However, it turns out that the lateralizing effect does not depend only on the expression of the cilia, as it also depends on the region where it is expressed, it requires the mixture of types of molecules that will be charged at this moment of embryonic development, such that this liquid stream acquires a certain flow and not another. If these same cilia were expressed at another point in development, they would not result in this effect. That is, the embryo actively works to determine the polarity of its own development.

There are endless examples of this type. That the owl can capture its prey in complete darkness by using its hearing is another trivial example of this nature. There is the owl perched, eyes open, but seeing nothing in complete darkness, and a mouse appears on the ground below, with its vibrissae and its olfactory epithelium, with its intermittent movements among the undergrowth, in search of something to eat. The owl turns its head in its direction, focuses on the mouse its eyes, which are blindly seeing nothing; when he has the animal in the center of his gaze, in his two foveae, he lets himself fall and captures the little animal. We can put lenses in this owl’s eyes during development; lenses such that what the owl sees is deflected by a few degrees, but even so the owl learns to hunt in the dark. And do you know how to do that? It orientates the glance in the deviated direction, but when it jumps, it corrects that deviation by the same angle.

There is a map of visual-auditory-motor projections in the upper colliculus, which influences the appropriate spatial network for these conducts. And how does this map develop? It appears in the experience of animal living. So, in a sense, the structure of the nervous system is continually changing as part of its developmental process, and it changes in a way that is associated with the animal’s interaction with the world. It is not the genes that do this. What makes the structure of the nervous system one, and not the other, is the pattern of activity that the animal develops in its relationship with the world. If that were not so, there would be no learning. However, this happens not only in the period of free life, but also in the embryonic period. As we have already talked about, if I block the movements of the chick inside the egg, it is born deformed.

Can I say, then, that we are on a structural drift? Yes, because this embryo that is in the egg does not have a “tendency” to become an adult. It is not headed anywhere, it has no direction. It does not contain a component that guides you through this process.

Look at the structural transformations. Evidently, you have a structure, which differs in each of you, and if I am going to examine the nervous system of different people, I will find different systems, which have peculiarities associated with their individuality, in a way that depends on life, history lived by each one. And also, I will find that the way in which a nervous system differs from the nervous system of this other one is associated with the history that was lived.

If you couldn’t have your nervous system right now, you couldn’t be who you are. But, by chance, did you come through life determined to be who you are now? When you were born, you thought: “Ah, on August 21, 2006, I will be sitting in that third row listening to a meaningless conversation about biological development!” Did you think that? Of course not. But how did you get here then? Think for a moment: anything that differs from what happened to you would make you not here. And the implication that all this has is not trivial, because any two people have different structures that make them private. Their biological structure is a consequence of the individual history they lived. And yet, these stories have not followed and are not taking a course; what follows is determined moment by moment. And it is such that the structure that the animal has at every moment is the only one that it can have and is adequate for the realization of its living at that moment.

Let us say this: when observing biology, I will see finalism, magical factors, until I realize that the course of these transformations is determined in the contingent history of the animal’s interactions with the world. What limits this is the maintenance of congruence with the world (which we call adaptation), because if this is lost, the animal dies. I want to emphasize, therefore, that adaptation, this correspondence with the world, is a condition of existence. Thus, all the changes we encounter occur as long as they allow the continuation of this adaptation of the animal to its world. Then, the organism changes following its history of relationships that it establishes. Relationships that, in turn, are determined by the structure of the organism at that moment. This is what happens in the learning process, in free life. And what happens in the embryo is the same. When two embryos are the same and follow an equal story, they remain the same.

Development is an active process that is preserved generation after generation; therefore, reproduction requires the preservation of this process. Reproduction is conservative, otherwise it would not be producing again. Of course, it allows for changes, but it is essentially a conservation process. Producing again consists of the repetition of a process of structural drift in ontogenesis, the reproduction of an epigenesis that results in a course of plastic transformations. So, the conservation of structural moments in this story is active, it is a consequence of the story’s realization. It is not a thing that occurs by itself.

This is an approach that treats reproduction as a way of limiting the structural changes that are possible along the course of transformations in the initial structure. There are many possibilities for change. Reproduction ensures the conditions that make it possible to repeat the ontogenic history that results in the embryo and, later, the adult. The organs and the organism are formed together, in the realization of the organism as a totality in a world; a totality that is the limit and the reference for changing the structural components, the organs. In phylogenetic history, the brain appeared with the brained animals; with them, not with their independence. And, in ontogenetic history, exactly the same thing happens.

In Figure 4, we can conceptually visualize the issue in this way: in the circular representation of the organism, on the left, we have the egg; and from there, there is a spectrum of possible epigenetic states. And how do these different epigenetic states arise? Studying different histories of organism / world interaction. If the story I follow, if the egg that was laid repeats the story of the parent, we have reproduction.

Suppose, then, that all courses that we are going to accept as the intrinsic variability of the species arise epigenetically, and if we change the initial conditions of the drift or modify them at any time, the course can take another direction. And the result may be different in the sense that, if we go back to the starting point, the original course is no longer reproduced. What happens in this Figure can be seen as a limitation of possible paths, as a consequence of the repetition of a history of structural drift. And, at the same time, another interesting thing is happening. What is kept is a limitation of what can be admitted as a change. If a change in the relationship between organism and world remains transgenerational, this may result in speciation (phylogenesis).

Figure 4  Systemic reproduction

What we represent in this scheme is the result of certain organism / world realizations. The different living beings, represented circularly in this Figure, are the results of realization in a relational way. If we change the history of relationships, then the result changes.

I will try to address this through clear examples. Suppose a turtle has been in its private habitat for two hundred million years. Many lineages became extinct, others were formed, the landscape changed, the continents separated, the water in the oceans cooled, then heated up, volcanoes came out, and there are the turtles, very conserved in their form and in their way of living. Nothing has changed in the world of turtles; the “turtling”⁵ remained the same. The changes in the environment have been catastrophic; a meteor fell, but from the turtle’s point of view, nothing happened. What matters is not the environment, but the relationship that the organism establishes with its environment, and if this interaction continues to be the same, nothing changes. The turtle results from turtling. It is the realization of the “turtle” way of life, it is the organism / world, organism / niche relationship that results in the turtle. As long as this particular achievement continues to take place, it doesn’t matter anything that occurs in the environment: there will be turtles there.

And everything that changes in the turtle changes around the conservation of that relationship. Larger scales may appear, for example. The other day, we had long conversations about the formation of the bone plates of the turtles, it would seem to be a very complex process, but in reality, this is accomplished by a very simple change in the epigenesis. It is a single slide, requiring a change in the direction of a single flow of cellular migrations. The axis of this migration changes, and it turns out that the scapular waist is inside the ribs. Then, the ribs form ingrained in the dermis and, therefore, calcify it, forming that bone shell typical of turtles. It is very simple in terms of the dynamics of development; however, it has an enormous phenotypic consequence. The same goes for the development of the extremities. Anyway, we can have countless examples of the epigenetic, I mean, historical, nature of the development process.

Any aspect of development that we examine shows this relational, systemic, process and outcome nature. This does not involve removing the DNA share. Evidently, nucleic acids participate, as do so many other molecules that are there.

There is another interesting point, which is the summary question of this nexus that is observed in ontogenesis. This, typically, is preserved in the phylotypical state of all chords. The general characteristics are developed first, and then the derivatives, and from this the idea arises that the initial stages of development have to be very conserved. However, if we analyze the initial modes of development of the vertebrate strains, prior to the phylotypic stage, we find that they are very different from each other. Amniotics segment themselves in one way; amphibians, on the other; fish have several different targeting modes. Thus, it would seem that the beginning has to be very rigid, but it turns out that it does not: the beginning is very plastic. There is plasticity at all times of development and, particularly, in the initial moments. Thus, cleaving inside an egg and cleaving in free-life, are different things, obey different restrictions. An amniote egg does not have to interact with a variable external environment, as it is enclosed in a shell. So, this establishes very central conditions in development. It is not certain that development is a fixed process, even if it is recurrent. There is plasticity at all times.

The neural tube can be formed in several different ways. Sometimes he does it by cavitation, other times by invagination. In the same animal, the most caudal part is formed by cavitation and the most rostral part by invagination. So, in the same animal, we have two forms of neural tube that are not homologous; one of the regularities is found in fish and the other in amphibians. There is plasticity in the ways of developing, because the paths of development have plasticity at all times. And that is what allows this wonderful diversity of lineages of living beings.

References

• HÄMMERLING, J. Uber formbildended Substanzen bei Acetabularia mediterranea, ihre räumliche und zeitliche Verteilung und ihre Herkunft. Wilhelm Roux Arch. Entwicklungsmech. Org. n. 131, p. 1-82, 1934.
• MATURANA, H. R.; MPODOZIS, J. Origen de las especies por medio de la deriva natural. O la diversificación de los lineajes a través de la conservación y cambio de los fenótipos ontogênicos. Santiago: Museo de Historia Natural, 1992.
• MATURANA, H. R.; MPODOZIS, J. The origin of species by means of natural drift, Revista Chilena de Historia Natural, n. 73, p. 261-310, 2000.

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Chapter 1.3 – Epigenesis

João Francisco Botelho

Historical considerations of the debate “preformationism versus epigenesis” and its consequences for evolutionary biology

The topic I will discuss is in vogue. I will discuss how the relationship between evolution and development is approached from different theoretical perspectives. I will try to contextualize and compare the current developmental approach to evolution, called Evo-Devo Theory, with two other more heterodox approaches – the Theory of Natural Drift and the Theory of Development Systems. I will argue that a historical reflection, far from the current vogue, can clarify the origin of some of the divergences that exist between these perspectives. The Theory of Natural Drift and The Theory of Development Systems are less known among biologists. The theory of natural drift is discussed mainly in Chile and among authors interested in theoretical biology (ETXEBERRIA, 2004; VARGAS, 2005). In the same way, Development Systems Theory is well known and discussed among philosophers of Biology, but ignored by biologists in general (STERELNY; GRIFFITHS, 1999; ROBERT et al., 2001). However, the lack of knowledge of these approaches by the empirical biologists is not due to a theoretical incompatibility. On the contrary, if we follow the history of Evolutionary Biology in the last thirty years, we will see that it is approaching more systemic approaches and moving away from neo-Darwinian reductionism.

Neo-Darwinism can be briefly described as extrapolation from the mathematical models of Population Genetics and their premises to other domains of Biology. Some of the premises of neo-Darwinism that I want to highlight are: the understanding that inheritance is accomplished through the transmission of genes; that development results from the expression of these genes; and that the evolutionary process is a consequence of the population variation of gene frequencies.

Evo-Devo has two origins – an empirical and a conceptual one. From the 1960s, neo-Darwinism began to face some empirical problems. For example, Kimura, comparing the same proteins in different vertebrates, proposed that nucleotide evolution follows a neutral pattern, that is, the main driver of gene evolution is not positive natural selection, but random variation (KIMURA, 1983). Kimura’s proposal does not seem very revolutionary in the light of post-genomic biology, when we know that all animals – including jellyfish and sponges – share about 75% of their genes. But it was carried out in a period when it was believed that “the search for homologous genes is useless, except in very related organisms” (MAYR, 1966). From Kimura’s original proposal to post-genomic data, it has become clear that describing the evolutionary process as the emergence of genes for phenotypes is inconsistent. One of the roots of Evo-Devo is precisely this need to appreciate the developmental effect of genes. Unlike neo-Darwinism, based on classical genetics, Evo-Devo, based on molecular genetics, describes the evolutionary process in terms of the spatial and temporal variation of protein production. As an example, I cite a work by Abzhanov et al. (2006) that investigates the molecular phenomena underlying the variations in the beaks of Darwin’s finches. The work describes the variation in the length and height of the beak in terms of the expression territory of Calmodulin and bone morphogenetic protein-4 (BMP4), respectively, and no longer in terms of genes for beaks kurtosis genes for wide beaks. In this case, the gene becomes a less pre-formation entity, that is, it ceases to be a “gene for the characteristic” and becomes a “developmental gene”.

What is perceived at Evo-Devo is an interest in developmental and morphological phenomena. Partly as a consequence of the transformation of Genetics into a “Molecular Biology of the nucleus”, closely associated with Cell Biology and Developmental Biology, the need arose – and the technical possibility – to open the “black box” of development to understand the course of evolutionary transformation. In other words, evolutionary biology found it relevant to investigate what happens between the first cell and the mature organism⁶ and not just play with the distribution of particles that determine morphology.

The other strand of Evo-Devo, which I call conceptual, came from authors dissatisfied with the hegemonic reductionist, pre-formationist and pan-adaptationist perspective in the 1960s-1970s. Among the pioneering efforts in this regard, Stephen Jay Gould’s book, Ontogeny and Phylogeny (GOULD, 1977), is recognized as a milestone. There is a passage in his preface that illustrates well the theoretical context of the period: Gould begins his book in a defensive tone, saying that he will address a “cursed” subject, and that his colleagues, although receptive to the possibility of parallels between ontogeny and phylogeny, recognized the “scientific taboo” that had been created around the theme. After more than thirty years, Gould’s eccentric interest is the main research program in Evolutionary Biology. Authors such as Rudd Raff (1996), Arthur and Brian Hall (1998), Scott F. Gilbert (GILBERT et al., 1996) have made Evo-Devo a consolidated discipline. However, despite important theoretical advances obtained with Evo-Devo, I would say that there was a theoretical “hardening”, similar to what Gould describes for neo-Darwinism (GOULD, 1983). Evo-Devo was born discussing about Bauplan, macroevolution, phenotypic plasticity, but today, in these authors, we only see the search for developmental genes, expression patterns of Hox genes, etc.; that is, with a few exceptions, the search is getting narrower again. And, in general, Evo-Devo ended up being implemented as something very close to molecular genetics.

On the other hand, Evo-Devo shares some important theoretical premises with neo-Darwinism. This approach remains attached to dichotomies such as “development x heredity”; “Hereditary x transmission”; “Innate x acquired”; “Nucleus x cytoplasm”; “Ontogeny x phylogeny”. These dichotomies are found neither in the Theory of Natural Drift nor in the Theory of Development Systems, as will be exposed later. In this context, I like a quote that makes the presence of this dichotomy in Evo-Devo very evident: “Developmental biology and evolutionary biology are two disciplines that explore morphological changes in organisms over time. However, development is genetically programmed and evolution is unscheduled and contingent” (RAFF, 2000, p. 74). It is this dichotomy, which sees development as something programmed and evolution as something depending on chance and necessity, that I think should be removed from modern biology.

Inheritance as development and development as inheritance

If you think that abandoning these dichotomies is not feasible, I argue in my favor that they are not as old as they seem, they emerged at the end of the 19^th century. Figure 5 shows its most well-known formulation – the Weismann-Wilson soma-germ separation and its Maynard-Smith molecular version.

Figure 5  Schematic representation of the germ/soma separation theory and modern representation of the Weismannian paradigm, the central dogma

These conceptions presuppose the existence of hereditary material, an idea that emerged at the end of the 19^th century (although we can find roots for this notion even further). It is even comical if we list the number of hereditary particles thought and proposed in the 19^thcentury. Practically, each author proposed his own hereditary particle. But, in addition to the anecdote, the conceptual genealogy of these particles is revealing, since their hereditary properties have undergone a historical evolution that, more and more, resembled them to the properties of the gene. Spencer (1864), for example, proposed, in the mid-19^th century, the existence of physiological units within each cell that represented the shape of the organism. Darwin (1883), on the other hand, postulated the existence of twin cells that represented the cells that contained them. During reproduction, the twins migrated and accumulated within the germ cells. The transmission and distribution of these twins explained inheritance and development. Later, Weismann (WEISMANN, 1893) proposed that hereditary particles were morphologically separated from the soma, isolated in the germ. Instead of collecting and redistributing the particles, he proposed a morphological isolation of the germ. In addition, Weismann, among others, gives a cytological substrate to the concept of hereditary material by relating particles to chromosomes. As a last example in this conceptual sequence, Hugo De Vries (1910) proposes that the hereditary particles, now called pangenes, no longer represented the cells that contain them, as proposed by Darwin and Weismann, but characteristics of the organism.

The similarities between the hereditary particles speculated in the 19^th century and the gene are clear. However, when we read Genetics history books or Genetics textbooks, the origin of the discipline is linked to Mendel and the rediscovery of his works. The contribution of ideas about the existence of hereditary particles is disregarded in the manner of the classical conception of the gene and the ontological premises of classical genetics.

And what do these premises represent if not a modern version of pre-formation? I say this not just as a superficial analogy. It was debated at the end of the 19^th century whether theories such as those of Weismann, De Vries and others were pre-formationists. For example, the title of Oscar Hertwig’s book: Pre-formation versus Epigenesis, the Great Problem of Biology today (1896). There was a discussion between pre-formationists and epigeneticists at the end of the 19^th century, but it was a different debate from that of homunculus versus misshapen matter that existed in the 17^th and 18^th centuries. It was not a question of taking pre-formation as the pre-existence of a homunculus in the sperm, nor of taking epigenesis as the form originating from amorphous matter oriented by vitalist properties. At that time, it was already known that an initial organization was inherited, that organisms started from a cell and that cell differentiation arose concomitantly with the multiplication of these cells. He wondered how the shape emerged from these processes of division and differentiation; and, for these questions, preformationist or epigeneticist answers were provided.

And what does this mean? In a pre-formation response to these processes, what determines the fate of each cell is simply its internal constitution. Weismann proposed that hereditary particles – which he called biophores – determined development. In the first division, biophores were distributed to make the right and left sides, and so on the fate of each cell was independently predetermined by the intracellular constitution. On the other hand, epigenetic theories stated that the destiny of each cell was built during development, based on its internal constitution and its relations with other cells. We can go back to the example that Professor Mpodozis mentioned earlier, about the stage of two cells of a frog, in which, if we kill one of the cells and remove it, the other cell develops into a normal blastula; however, if we leave the dead cell adhered, the other one develops in half a blastula. Or, as Driesch did, who took hedgehog embryos, shook and separated the two cells from the first division, each giving rise to a complete larva. The regulation and compensation relationships that are established between cells are part of the ontogenetic process.

There was clearly this dichotomy, and Genetics recognizes that it came from pre-formation. Weismann said he did not understand why Darwin included a preformationist theory, and says that he tried to promote epigenetic ideas, but failed and ended up accepting the pre-formation. In the same way, other epigenetic scientists also ended up adhering to a pre-formationist conception – in my understanding for heuristic reasons, that is, there was an experimental difficulty to approach these problems from an epigenetic perspective – Embryology did not take off, despite its great achievements.

On the other hand, the pre-formation perspective followed with Genetics and the chromosomal theory of inheritance, that is, when associating Mendelian patterns with meiosis. And it is in this period – the beginning of the century – that we see the dichotomy between inherited and developed, between innate and acquired. Like many authors, I also identify Morgan’s works as great divisors, creators of the dichotomy between transmission versus development in the biological sciences of the 20^th century. In fact, Morgan’s scientific history is very curious: he was an embryologist, an epigeneticist and studied the topic of regeneration. He was one of the first authors to use the idea of gradients to explain development, but he ended up becoming a pre-formationist. The “conversion of Morgan to Genetics”, as the change from leaving Embryology to founding the Gene Theory is called in the literature, is something that each author has an opinion on. I think that maybe it happened for heuristic reasons, like an act of despair, after spending 15 years trying to explain development as something epigenetic without great success. I really like his quote:

For the purpose of a more precise analysis, it seems desirable in the current conditions of Genetics and Embryology to recognize that the mechanism of distribution of hereditary units or genes is a type of process entirely different from the effects that genes produce through the embryo’s cytoplasm agency. (MORGAN, 1919).

Indeed, it is as if he were saying: now we are going to research how the transmission of characteristics occurs and then we try to understand Embryology. And he did try, because he was an embryologist. He later published a book called Genetics and Embryology. There was even a report that an embryologist at the time asked him: “I read your book and saw Genetics, but where’s the integration with Embryology?” Morgan would have replied: “there is no integration, I said in the title: Genetics and Embryology – they are two different things” – and these two themes have really remained separate!

The consequences of this separation were as follows: placing the gene expression in a black box and studying just how changes in chromosomes had developmental implications (Figure 6). The metaphors of cybernetics, information theories, information technology, the sequencing of the double helix, DNA, genetic code and all these things have emerged, and everyone knows the details well.

Figure 6  Morgan’s conversion and dichotomies in Biology

What happens with this story is that, from the eighties of the twentieth century, it is not so successful. We had started with the proposal for an instrumental gene – a gene to measure something that must exist on the chromosome; something that, from connection tests, is postulated to be written on the chromosome as a particle that determines inheritance; something that later is related to DNA. Several authors publish that particle is a DNA sequence that has the information for a peptide. It turns out that, from the 1970s to the 1980s, many molecular phenomena emerge that make the correspondence between the classic gene and molecular genetics become impossible. There was no way to relate these two things anymore. There is nothing in the cellular machinery that we can call an allele, pointing out “this is allele, this is this DNA sequence” – this is no longer possible in molecular genetics.

Likewise, a little later, we had the explosion of Developmental Biology. Embryology would finally become molecular and owes a lot to Genetics, particularly Developmental Genetics and Cell Biology.

It began to elucidate how cells communicate. What did that cell, which remained attached to the frog embryo, say to the other? Now we know that there are transcription factors, among other things. So, initially, we had a gene that was a phenotype in the fly (Figure 7A); then it is noticed that a fly, whose eye is red, usually has a certain type of bristles or is usually a male, which allows the construction of a chromosomal map. Then the structure of the double helix was elucidated, there was a technological explosion produced by molecular biology, and there is now a time when, if we look at a gene in a book on Genetics, we see something like the diagrammatic representation in Figure 7B – a huddle of introns, exons, promoter, amplifier; all entangled with activating and / or repressing factors of transcription, proteins that participate in the processing of RNAs, etc.

Figure 7  The classic gene and the molecular gene

This is interesting because when we look at this molecular object, it is not actually a molecule, it is a kind of process. This is a gene-process! Eva Neumann-Held is a researcher who works with development theory, and she puts the gene that way. For her, the gene is not an entity, but a process. And this is evident, what Mendel saw in his peas was not an entity, but a process. And notice how this is not just a semantic change, but something fundamental, because, in the same way, the inheritance of this process requires a process, it is not the inheritance of a particle. When reflecting on inheritance, we have to think about a process that uses each cycle. As Mpodozis would say, it is the legacy of a systemic relationship between these components.

I’m not going to say that you can’t talk about a gene in that simplified way anymore; some diseases really Mendelize. One can also talk in terms of a “defect gene” in some very particular circumstances. For Medicine, perhaps this is still important, but with great care, because, thus, there is a risk of conceiving a genetic determinism as if it were in a particle. We can no longer say that the gene is a particle that Mendelizes – we have to illuminate the black box and understand what happens: understand how a protein reaches its three-dimensional structure and how it entangles with the system in which it participates.

So, the problem that still exists in Evo-Devo, but that the Theory of Developmental Systems and that of Natural Drift go further, is the failure to abandon all this: the idea of hereditary particles, the chromosomal theory, the Mendelizing and the development as pre-training. We need a language that makes the epigenesis explicit, let go of Morgan’s bifurcation and all these other bifurcations – see phylogeny as a series of ontogenies.

The concept of transmission is related to the idea of a genetic program. Therefore, there is no longer any sense in addressing the issue of inheritance as transmission, but as development. And this is not so incredible, because, before Morgan’s theory, this was how this topic was treated. Inheriting was like developing a similar shape and building something similar to what the parents built, like reproducing. And this remained so, until, around the 1930s, French doctors began to use the idea of inheritance metaphorically, referring to diseases: e.g. you will inherit the house and myopia from your parents. But it is worth emphasizing: inheritance is a metaphor. There is a comment by Johansen (1911) that points out that inheritance is a bad metaphor, and that he would prefer a construction metaphor rather than a transmission metaphor. And this is an idea that is reappearing in the evolutionary approach to Biology.

But at the same time, if we see a video of an egg developing, it is such a coordinated process that it seems difficult to explain. And, if we do not accept that organisms are preformed in their eggs, then we need to provide another explanatory proposal that gives rise to this phenomenon. How can we explain, then, a process like this without the idea of a program? I will try to show, in sequence, how two theories approach this problem.

Development Systems Theory (DST)

DST arises from the ideas published by Susan Oyama, in 1985, in the book The ontogeny of information. More recently, a collection was published with works guided by the perspective DST, edited by Oyama together with Russell Gray and Paul Griffiths, Cycles of contingencies, systems of development and evolution. The great empirical inspiration for DST is Developmental Psychology – a discipline that emerges as a critique of the dichotomies implicit in the approaches to Behaviorism and Ethology. In these two approaches to the study of animal behavior, the source of the behavior is kept in a black box. What did the behaviorists say? Stimuli and responses. Of course, it was not so naive, it was instrumental in wanting to make psychology a testable science; but the fact is that, between stimuli and responses, Behaviorism did not focus on the organism. And, in turn, what did Ethology do? It saw an innate characteristic and attributed it to a gene. However, Developmental Psychology is aware of this epistemological obstacle and eliminates this black box – it is concerned with studying how these behaviors are historically constructed. It is no coincidence that both Oyama and Maturana, Varela and Mpodozis today are major influences in the cognitive sciences.

Many of these wonderful examples explored in previous essays by Mpodozis are, in fact, similar to those of Developmental Psychology. Like, for example, the chick that is born scratching. Why is he born with this behavior? The discussion was: he must have one (or some) gene (s) to scratch, it is innate; or, on the other hand, because he is born and sees a chicken scratching, it is a learned stimulus. Then, Kuo (1967) shows that it is not so and, in a series of very elegant experiments, demonstrates that, when the chick’s heart begins to beat, the beak begins to make movements (open-close); with this, the liquid inside the egg starts to move, and as a result the chick also moves as if it were scratching inside the egg – that’s why it is born by scratching. What this researcher shows through this example is that, regardless of whether we call it an innate or acquired behavior, we have to go inside that black box and see how it arises, its epigenesis.

I think that Developmental Psychology has taken a very interesting step by abandoning the concept of innate. It may seem that it is not plausible to abandon this term, but it does not tell us much. Realize: what do you mean when you use the term “innate”? If innate refers to something that cannot be pointed out in the history of the development and construction of this conduct in a free life, that is fine, even if it does not explain anything; but if we want to call something that is repeated over and over again because it is determined in the embryo, in its genes, then it is a mistake, because we have to explain how it arises. Realize, it is said that something is learned when it is possible to show the historical circumstance in which a possible new conduct depends on the history in which it was established. That is, a behavior is learned when I show that this behavior results from a historical series of particular relationships. And, when this cannot be shown, this conduct seems to us to be inherent in the entire lineage and independent of individual history; we refer then to it as something innate. But, even when talking about innate, it is also necessary to show how it is established, and in this case, one finds that it is established in the course of development, during the initial epigenesis, in some way. And what Kuo’s experiments demonstrate is that this is not established in any way, but associated with the conduct patterns that the animal actively develops during this process behavioral characteristics as important as pecking seeds in granivorous birds. Even when it appears to us as innate, neuronal and neuromotor machinery mature in the pecking action of the animal during its embryonic life. This is a very beautiful and very clear example.

So, going back to this broader perspective that is DST, I will try to put the main arguments in a series of topics below. In the sequence, I will also do the same with the Theory of Natural Drift, so that we can compare them and see in which they approach and in which they differ; in short, how one can fill in gaps in the other. The first idea I want to expound seems very obvious and clear: DST rejects pre-formationism:

a) Non-preformationism

DST rejects the idea that there is, in DNA, a project or representation of the characters of the organisms and combats the notion of pre-formation even as information. The frequently expressed understanding that Genetics obtained a synthesis between pre-formation and epigenesis is abandoned at the expense of real epigenesis.

I venture to say that if we ask students whether Biology is currently pre-formationist or epigeneticist, those who try to answer it will say that it is not so, that Genetics brought a synthesis between these two things. This is an idea very much defended by some authors, such as Mayr, Gould, Jacob. But this is something serious and it is an argument that DST does in fact challenge in favor of an epigenesis taken seriously.

b) Causal cointeraction

To claim that characters are influenced by both genetic and non-genetic factors is a truism. Even Genetics recognizes the interaction of the environment in concepts, such as norm of reaction and polyphenism. However, according to DST, this interactionist consensus (GRIFFITHS; STERELNY, 1999) does not solve, does not represent a synthesis of the nature / nurture dichotomy. Oppositions between genes (or biology) and learning (or culture) are inadequate for understanding ontogeny and phylogeny. A more appropriate notion is that of nature via nurture.

There is no such thing as innate or acquired, because everything is built and developed. Darwin, in his book on ontogenesis, spoke of congenital characteristics that are not inheritable. That is, attributes that were in the entire population, as a result of everyone having the same development and the same influences. In Darwin, there was no separation between development and transmission. This dichotomy, as I had initially approached, and as DST explicitly rejects, confuses the historical aspect of the building of organisms. This question that insists on asking itself: “Are genetic or environmental causes of this phenomenon?”, is poorly addressed. All respond that they are both and this dispute remains to say, in each particular situation, who is more important, whether the genes or the environment. This does not explain much to us, because it hides the development and construction of the characteristic in question. It is not both, it is one thing, and that does not mean that the two won the dispute, but it does mean to abolish this dichotomy.

In the sequence, I would like to point out an explanation that I consider more interesting in this perspective:

c) Dispersion or causal parity

DST does not recognize centralized or dichotomized causal power. The cause of development does not lie in a particular class of entities, but is distributed in the interaction of all development resources. The distinction of genes as “replicators” and everything else, from plasma membranes to human culture, as “interactors”, is replaced by the concept of causal parity, in which all elements and relationships are considered equally essential. As Bateson (1978) says, stating, like Dawkins, that the body is just a way for genes to make other genes, is the same as stating that genes are just a way for nests to make other nests. Development is a process of self-organization, with no external or centralized source of control or information.

d) Expanded inheritance

The usual way of privileging genes over other causes of development is to argue that genes are the only structures that are inherited. DST suggests that the phenomenon of inheritance involves much more than genes. It insists on a definition of inheritance that recognizes the wide variety of resources that are passed on from one generation to another, thus being available for the reconstruction of the organism’s life cycle. Jablonka and collaborators deeply developed this idea with the concept of an epigenetic inheritance system (JABLONKA; LAMB, 2005; JABLONKA, 2002). She is an interesting author in this context, and, in the dedication of her latest book, she writes something that exemplifies her ideas very well. She writes: “To my parents, who gave me more than genes”.

The resources that make up the epigenetic inheritance system range from genes, organelles, membranes, to environmental resources altered by past generations, such as burrows and language. What DST seeks to make clear is that inheritance is a developmental problem – we develop the same. It is not merely a matter of receiving something that our parents had.

There is an example that addresses this issue very clearly: pogonophores, which are modified annelids. They resemble polychaetes, but they are massive, with no digestive tract – they are like giant sausages living four thousand meters deep. How do they live if they don’t have a digestive system? They perform mandatory symbiosis with bacteria capable of chemosynthesis from the sulfur that leaves the oceanic abyssal pits. And how do these pogonophores acquire such bacteria? With each generation, they are infected again. They are born without it, but it is part of their life cycle. Now, can we deny that this is a fundamental part of your development process (an inheritance)? In this case, having these bacteria is part of being a pogonophor, but there is no need for a particle that specifies and transmits this.

e) Contextualism and contingency

Contextualism is the view that development resources, be they genes, chromosomes or nests, have no meaning in themselves, but only in the context of other development resources. The presence or absence of these development resources is contingent. The apparent precision of the development phenomenon does not evidence the existence of a genetic program. The tendency to minimize the importance of context and contingencies in development is connected to the prevalence of the information metaphor and the genetic program in contemporary Biology. In these metaphors, genes are attributed an idea of precision and independence of context.

f) Development as construction

At DST, development resources are “passed on” in the sense that they become available during the next generation’s life cycle. Not as a hereditary material carrying a program for development. The phenotype is not transmitted but reconstructed by development. There is a shift in the approach from heredity as transmission of characters (or coded representations of characters) to a continuous developmental construction of the organism and its world. The life cycle of an organism is reconstructed every generation through co-interactions between the organism and the environment.

g) Evolution as construction

According to Lewontin (1997, p, 104): “evolution by adaptation is the evolution of organisms coerced by the existence of an external and autonomous world to solve problems that they did not raise; their only hope is that the random force can come up with the solution”. This author argues that, due to the ability of organisms to choose and modify the environment in which they live, Evolutionary Biology must value the action of the organism itself in the adaptation process. Furthermore, “adaptation” can also be considered as an inadequate metaphor that would be better replaced by another more appropriate as “construction”.

So, for the authors of this perspective of development systems, not only ontogeny, but also evolution appears as a construction, which is a very interesting treatment. It is very common to find, for example, classic evolutionary explanations that treat the niche as an attribute of the environment, merely spaces to be filled by organisms. However, in theories such as those discussed here, the authors propose something like the construction of niches, something that happens dynamically and actively in the way of living of organisms in relation to their world. Thus, it is not that sloth and koala occupy the same niche, they have similar niches, but each actively creates its own.

h) Life cycle selection

The last point that I highlight from DST is the idea of selecting life cycles – its authors continue to see selection as an important factor for evolution. This approach proposes that the units of natural selection, instead of genes, organisms or groups, are life cycles:

Evolution occurs when there are variations during the replication of life cycles and some variations are more successful than others […], one variation is better than the other, not due to a correspondence between it and a pre-existing characteristic of the environment, but because the life cycle that includes interactions with those characteristics has a greater capacity to replicate itself than the life cycle that lacks that interaction. (GRAY; GRIFFITHS, 1994, p. 139).

In summary to these exposed topics, Figure 8 is the only one that I know of these authors and I ask you to try to observe it in comparison with the Weismann scheme (germ-sum separation) and that of Maynard-Smith (DNA-body) (Figure 5, p. 31).

Here, the development no longer has forks between something passed on and something transmitted. What there is here is a series of processes for each organism, and for it, a series of development resources contribute. There are, for example, some persistent features, such as gravity. In the absence of gravity, no healthy development follows; in the case of the Xenopus laevis egg, it does not even reach the two-cell stage. There are also what they call collectively generated resources; for example, moles live in burrows, ants and bees need pheromones from the colony. Of course, there are parental resources, which we know so much today, and even self-generated ones. All of these resources contribute equally to development; there is no reason to give priority to a particular class of them, or only to those generated from DNA. The development process, for the proponents of DST, is the confluence of a series of resources, contingently, but which are repeated and end up allowing the process to be repeated. It is more plausible for us to understand the development being kept conserved as a consequence of the entanglement of all these processes than being something dictated by a molecule present at the beginning and that contains the end.

There is a very valuable metaphor at this point, which predates the DST itself, which compares the process of individual development with the process of ecological development (Figure 9). Let’s imagine a very old, diverse and stable forest, but suppose it passes a glacier and removes everything. Then moss, shrubs, ferns, pine trees grow, then trees. And this process is always repeated. This is a good metaphor for thinking about the cause that makes the process recurrent in individual and ecological development. Can we say that there is a genetic program for this ecological succession that we always see in a similar way? No, there is not; but there are birds, winds, light and a series of factors that are repeated every time I open a space in a poultry. There are trees that lack the sun and then develop quickly when the clearing is opened; then other plant species appear that need shade to germinate and that only do this after other trees are born. Can’t we see something similar with an individual’s development? We do not need a preform form to explain this, as there are a series of relationships that are repeated between the cells of an organism, in the same way as the relationships between species in an ecological succession. This is contingent; it has no program, even though it is contingent on a recurring and preserved basis. I think this appreciation of ecological development is very valid as an analogy to ontogenetic development. And the interesting thing, in this case, is that this ecological phenomenon is evidently epigenetic. Or does anyone think there is a preformed ecosystem there that has simply grown? This seems to me to be a good example, in the sense that each state is a condition for the accomplishment of the next.

Figure 8  Schematic representation of the different development resources for DST

Figure 9  Ontogenesis and ecological succession as epigenetic processes

Natural Drift Theory (NDT)

In a very fundamental way, for the authors of this explanatory proposal of Natural Drift, the history that the organism follows is taken seriously, and the phenotype is always a construction. That is why this approach dissolves that adult-centric idea that we do not like as biologists, that is, there is no ready-made organism, or an end point. We humans don’t have a program to reach twenty-five years old, reproduce and, after that, start senescence. The phenotype is a point in the history of a process. In other words, it is an “ontogenetic phenotype”, to use the same terminology as Maturana and Mpodozis (1992; 2000). If we were to take this notion of an adult, ready-made phenotype seriously, whose plan for its construction is lying on the individual’s chromosomes, then what would the phenotype of an alligator or redwood be like, which grow indefinitely? It does not make sense to take this adult-centered and pre-formationist dimension of Biology seriously.

I believe that I do not need to repeat the details of what has already been mentioned in previous moments, in the chapters conducted by Professor Jorge Mpodozis on the Theory of Natural Drift, unless I emphasize that this reconsideration of history in Biology delights me, because I consider this a central factor to seriously understand living. And, in addition to this truly epigenetic treatment of Biology, this explanation by Mpodozis and Maturana (1992, 2000) also seems essential, because it approaches organisms as de facto systems. That is to say, its emphasis is not on the function of genes that control development, or on hereditary particles lying on the double strand of DNA, but on the organization of living systems and their way of living. And, if we take seriously what was previously put to us by Mpodozis about “structural determinism”, that is, if we really consider that fish and the operation of its nervous system (Figure 2, p. 37) are determined at every moment by the architecture of its structure, if we take into account that the phenotype is a historical construction, and if we accept that reproduction is a systemic phenomenon, then we can envision living as a spontaneous, natural drift.

The natural drift of development systems

We can compare these two theories briefly. Recently, Fox Keller, the author of The Century of the Gene, wrote an article for Biology and Philosophy called “DDS: dynamics of development systems”, complaining that Oyama, Grifhitis and Gray’s approach seems to turn its back a little for the theories of systems themselves in Biology. It demands that they approach the so-called systemic biology. Personally, I claim that we could talk here about natural drift of development systems instead of talking about life cycle selection.

To better compare these ideas, I present a comparative table, summarized, with some of the main concepts of each of these two approaches (Table 1).

Table 1 – Comparison between Theory of Natural Drift and Theory of Developmental Systems

Natural drift	Development Systems
	Non-preformationism
Emphasis on structure	Causal co-interaction
Systemic reproduction and total genotype	Expanded inheritance
Emphasis on structure	Contextualism
Biological processes are not teleonomic	Contingency
Ontogenic phenotype	Development as construction
Ontogenic niche	Construction of niches
Structural determinism	Dispersion or causal parity
Natural drift	Life cycle selection

It is possible to notice that they are very similar in some points, have similar assumptions, and we can see a series of correspondences. Expanded inheritance, for example, is discussed in both cases – neither proposes it simply in terms of DNA transmission, or that a specific part of the cell is responsible for the structure and organization it forms; the idea of contingency (DST) is comparable to the notion that biological processes are not teleonomic (Natural Drift); development as construction, in the approach of development systems, is similar to the ontogenic phenotype proposed by the authors of natural drift; construction of niches (DST) and ontogenic niche (natural drift). All of which makes it clear that these theories have several similar assumptions. They are the ones that take construction metaphors most seriously, it seems to me.

There are, however, still two concepts in which these theories diverge. First, I believe that the concept of structural determinism, included in the discourse of Maturana and Mpodozis (1992, 2000), differs from the concept of causal parity (DST). Coincidentally, this is precisely the most criticized point in DST – the idea of causal parity. If we say that the environment is a cause for some processes, then, doesn’t the organism lose its autonomy? Thus, if we say that temperature causes, instead of triggering, processes that differentiate sex, then the organism becomes hostage to the environment. Thus, we would be bringing to ontogeny the same point of phylogeny that places the organism as passive and shaped by the environment (as Lewontin says, an excessive externalism). In this context, I think that structural determinism, proposed by Maturana and Mpodozis, solves the problem. If an organism is determined by its structure, then the environment does not shape it randomly, but only triggers changes that the organism allows it (Figure 2, about fish and its nervous system, p. 37).

In addition, the second major point of divergence between these two approaches focuses on the course that history follows. That is to say, both perspectives take seriously the historical condition of living systems. But how do you try to explain now how this historical becoming is determined? Mpodozis and Maturana speak in terms of a natural and spontaneous drift determined at each moment by the encounter between an organism, constituted by operational enclosure, and its environment; and they do so without mentioning the participation of an external guiding force. In turn, and in a very discordant way, the notion of selection of life cycles still seems to be an important guiding factor in the way in which the construction of living systems follows, from the perspective of DST. That is, for DSTs, it is no longer the genes, nor the organism, but the life cycles that would be the appropriate selection units. But are they really?

In this scenario, let me disagree with Mpodozis, who says that Natural Selection is not a mechanism, but a result of what is going on. I think it could be a mechanism, if some conditions were respected. I believe that Natural Selection, as Darwin proposed, and not Wallace, could be a mechanism; but for that, we depend on a long series of assumptions and a theory of inheritance. As Gayon (1998) says, in his book, The struggle for the survival of natural selection, this theory faced a long battle to establish itself, until Genetics emerged, which indicated a substrate for evolution consistent with the idea of particle selection. And, since we no longer have these genes from classical genetics and this theory of inheritance, if we wanted to maintain a selectionist explanation for evolution, then we would need another theory that would explain the selection of another replication unit. And, for it to be truly a positive selection, this theory would have to respect five assumptions, according to Sterelny (2001):

a) Variation and range of possible phenotypes

The variation must be abundant, not directed and of little effect. If not, the variation itself, as advocated by Huxley’s saltationism and the mutationism of De Vries and Bateson, will be responsible for the direction of the evolutionary process. Here, at the outset, I think the idea of selecting life cycles is unsustainable. We can hardly accept that the variations in life cycles are always gradual and not directed, mainly due to the active role of the organism.

b) Continuity and fidelity

Inheritance units must have continuity and reliability for several generations in order for the selected units to accumulate. As for this principle, there is no reason to reject life cycles as inheritance. Despite the contingent nature, development resources, such as salinity or a symbiont, can be relied on reliably.

c) Vertical transmission

Vertical transmission occurs from parents to children. Genes and mitochondria, for example, are transmitted vertically. But this does not happen with many development resources, such as, for example, behaviors and systems of lair, where transmission is diffuse and horizontal. A mole that digs a tunnel leaves an important development resource for the entire population and not just for their direct descendants or close relatives. An extreme case of horizontal transmission is the fixation of nitrogen by legumes (in symbiosis with bacteria), a fundamental stage of the nitrogen cycle that allows life as we know it.

d) Developmental modularity

In order for cumulative selection to occur, the selected characters must be almost independent. The character development path must be modular, that is, there must be partial integration, so that each character can be manipulated independently by selection. Although there are certain relatively modular structures (e.g. the tetrapod member), the developmental resources that contribute to a life cycle usually have a pleiotropic effect.

e) Delimiting an individual life cycle

For a positive natural deletion process to work, the inheritance unit must be individualized. However, the joão-de-pau (Phacellodomus rufifrons), for example, is one of the most famous representatives of the large family of Neotropical birds Furnariidae. The fame of the joão-de-pau is due, above all, to the showy and elaborate nests of spiny twigs that he builds. They are built and abandoned on the same tree each year. Abandoned nests are often occupied by Molothus badius and Icterus jamacaii. In the nests, the entire life cycle of the blood-sucking bug Psammolestes coreodes is also carried out. Also, the nest of João-de-pau is commonly parasitized by the Chopim (Molothus banariensis) which lays its eggs for the other species to hatch and raise the young (Icterus jamacaii is also usually parasitized by M. banariensis). There is no way to separate the development resources of each species, so that a given life cycle can be selected without influencing the life cycle of the other species. The eventual selection of the life cycle of one of them would influence all the others.

And, in order not to be unfair to DST, I must say that, although they accept the idea of selecting cycles, they also accept other notions, such as the Lamarquist dimensions of Jablonka’s ideas, the concept of exaptation, etc. But I think that this assumption of selection of life cycles, defended by them, is not supported. They either abandon this conception, or they give up other assumptions and end up having a theory of replicators, like Sterelny’s. I would prefer to change the metaphor, as Oyama says (2000, p. 81):

As we understand the process that produces stability and transgenerational change, we can continue talking about natural selection because the concept has expanded with our knowledge (e.g. to accommodate reciprocal influences between organism and environment) or we can decide that the term is so closely linked to undesirable implications (stasis, action of an agent on a passive object) and choose another.

Perhaps it is the case for DST: be more careful, do not bother to abandon the selection metaphor – which, yes, it is a metaphor – and start speaking in terms of a drift.

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Chapter 1.4 – Phylogenesis

Jorge Mpodozis

Now, I intend to talk a little about phylogenesis in the context of this epigenetic ontogenesis that was previously discussed. I believe there are sufficient elements for this, given the richness of the previous essays. So, we can walk many paths in this conversation. I want, before any discussion, to take you on a tour of the world. Where are we going first: Chile or the Galápagos?

In Chile, a curious thing happens from the natural point of view, because the country is like an island. And there we live in a world that belongs to Chileans. Chilean geography is isolated and Chilean nature is also peculiar, because it developed in isolation; it is a region of a continent, but it has an island characteristic. An interesting thing that happens there is that there are “foggy forests” – a forest fed by coastal fog. Near La Serena, north of Santiago, we have a temperate, cold forest, in which there are trees twenty meters high and other plants associated with a rainy climate, and which is on the banks of a hill, facing the coast. You walk ten steps out of the forest and enter a field with cacti and annual plants, which bloom only after the rainy season and, in a short time, disappear; and the species that emerge vary. We walk towards the coast and there is nothing except a few seagulls. And the forest is there, and the species that form it are unique, and the genera to which these plants belong have floristic relationships with the Yunga forest, in Bolivia, and the Tucumana jungle, in Argentina.

How long has this forest been in existence? Thirty million years ago; it is a relic of when this flora spread throughout America; it is part of the Cordillera da Costa, and also of the Andes, but it is much before the emergence of the Andes. This particular flora spread throughout the American peritropical belt. Then there was a major climate change, the Cordillera da Costa rose, the Chilean climate became semi-arid on the one hand. The Atlantic forest that developed continued to change, but this forest that is there on this hill is fed by the moisture that comes from the sea. A mist forms that goes up that hill, and the shape of the place is such that it allows the fog to condense on the forest. You enter it, it is cold and it is always humid in the middle of summer; you walk out of it, and the temperature is 25 ºC; inside the forest, it is 12 ºC, it is dark, cold. This is something that is not found anywhere else in the world.

The dominant trees that are in this forest are also in other parts on the coast of Chile, in other forests that are 200 km south of the first, and still others that are 700 km further south; in fact, they are an ancestral fragment of the ancient forest. It turns out that a lot has changed since that forest arrived there. The trees have changed, and the entire biogeography of the planet has changed radically. And there is the forest, 30 million years ago with the same floral composition. This cannot be studied much because there are no fossil pollen records for a more accurate floral characterization; we can do it two thousand years ago, but not for 100 thousand or 500 thousand years. But at least two thousand years ago, the forest was the same as it is now. Sometimes it expands; sometimes it contracts, but it remains there for thirty million years. Then, the world was transformed, the environment was transformed, but the forest was not.

And next to it, in the desert, are the desert plants. And where do these plants come from? Some come from the woods. In the woods, they are trees; in the desert, they are annual shrubs, small. When did they get there? Twenty, thirty thousand years ago. The seeds of desert trees arrived thirty thousand years ago and formed species that were very adapted to the aridity and the conditions of annual germination. So, we take a few steps and enter another world. Seeds here, are in the woods; seeds there, are in the desert. All species of the desert are new, they are forming all the time. There are studies on genetic variations of plants in different desert cliffs; it turns out that they are genetically different in each branch, from plants in adjacent branches. There is, therefore, a very high divergence. Plants have this capacity: here they are like trees; and over there, they are like herbs. The desert flora is rapidly establishing itself, changing and changing, alongside this ancient forest, which has been there for thirty million years. There is conservation on one side and change on the other, and the line that separates the two regions is as narrow as a trail. This is interesting because change and conservation can be observed in the same place, in a phyletic, genetic sense.

How do we explain the conservation of the forest? From the point of view of the forest, the world, that is, the niche where that forest exists, and the network of relationships it establishes has never changed. The environment has changed a lot, but the niche has not changed at all. It was the same with the turtle we discussed earlier; the turtle has been in the turtle world forever. No matter how the environment was transformed, the turtle’s niche – seen as an organism / world relationship, and not merely an attribute of the environment – continued to be realized. The niche of the forest continued to take place there, under these conditions. In turn, the other plants, those that arrive in the desert, are changing their niche. Each time a new seed arrives, it changes niche. And it is precisely in this situation where the niche changes that we find changes.

What happens to the plant when its seeds reach a new niche? It may be that nothing happens and that there is no change in this relationship with the world; but if the niche changes, a different plant appears. And this new different plant will be conserved or not transgenerationally.

With the huge Galapagos tortoises, something interesting is going on. They make their nests, lay eggs in holes in the sand on the beaches and leave. After a few months, the eggs hatch, the turtles dig and come out of their holes and immediately go to the forest, which is characterized by being cold-tempered, humid. Galápagos has a semi-arid climate like Chilean, and on the beach, the temperature can be hot, 25 ºC; but the forest remains moist and cool. It turns out that some turtles, which are in the deepest holes, have a harder time getting out; 4-5 days pass and do not leave. And during that time, they have no food other than the remains of the yolk sac. Finally, some die; others leave, but leave with a metabolic exhaustion, and do not grow like the others that reached the forest; and when they reach sexual maturity, they are still small. So, there are two types of turtles in the Galapagos: the large ones, which hatched first, and the small ones, which hatched later, malnourished. At the time of reproduction, these turtles go up the hill to the summit, to mate – the reproduction of the turtles is very curious. However, smaller turtles are unable to climb the hill and mate with other small turtles halfway. Then they go to the beach and lay small eggs, from which small turtles come out because the eggs have little yolk sacs. This is how species are separated.

And can something like a desert plant occur? Yes. If I take the seed from a desert plant, which lives in a medium lacking in nutrients and moisture and place it in a moist and nutrient-rich environment, it may not grow or develop as a different plant. So, what am I saying? There is a niche change that occurs as the emergence of a new epigenetic result, because what has changed is the organism / world relationship. In the foggy forest, this bond does not change: for thirty million years the relationship of plants with the world, and that of each one of them, and of all of them with the environment where they are, has not changed. So, the ontogenic niche continues to be realized, the animals continue to reproduce, and these strains are conserved.

When does a change occur? It occurs when, for whatever reason, there is a change in the animal / world, or plant / world relationship, from which a new animal or a new plant arises. This change is a possibility for the ancestral being, which can occur in a sporadic way, or in a circumstantial way, or in a systemic way it can start and be systematically conserved, as in the case of turtles. And if that occurs, then a new lineage appears, as a derivation from the ancestral lineage. And it will emerge whenever there is a change in the animal / world, or plant / world, or organism / world relationship, because, you see, the direction that follows the epigenetic history is the direction that follows the organism / world relationship.

See what happens in the passage of the animal in the egg to free life and adult life. In the egg, I have the animal in its initial niche; there, I have the little turtle in its egg. The niche is not the environment, the environment allows the niche to exist, but the niche is what the animal finds. And this will give an epigenetic condition that will follow the direction of the animal / world realization, because this is a relational story; there is a dialectic. Every time an interaction occurs and that animal changes, it finds a new aspect of the environment and a niche will emerge that has the consequence of the emergence of a new posture, which results in the meeting of the new niche. This, in turn, results in a structural change, which results in the emergence of a new level of interaction. This is an active process, a dynamic that occurs with the animal’s participation in its own development. In other words, these animals are the main actors in their historical transformations, and not merely patients of what is going on, both in ontogenesis and in phylogenesis. That is why examples are so important, such as those that Botelho presented earlier on the origin of the behavior of a chick’s scratching, which demonstrate how what the animal does, during development, has consequences on its way of relating with the world where it is, and that, in turn, has implications for what is going on with it.

In the historical development of development, I have a possible result that I imagine (an animal in its reproductive stage); but if the story is different, the animal that results is another. As in the case of turtles. So, what do I have to do so that the history that is preserved systematically becomes another? Well, I have to keep the contingencies in order for this story to be possible. In principle, what we can say is that when a lineage is transformed, not only does a clade separate, that is, a different organism / world relationship is separated, a new relationship as possible as the ancestral relationship, but that still it is a new relationship. It is an optional possibility of the old one. Optional because it may not change permanently; or it goes on like this, the novelty lasts for a while, until, at a certain moment, it establishes itself. When it begins to be conserved in a systemic manner, then the new lineage separates from the ancestral lineage. What separates, however, is the possibility of an ancestral epigenetic history.

It is worth mentioning another situation in the Galapagos Islands. The sea lions are there on the beach, the females and the males, and we can get closer; without getting too close to the females, because the males get irritated. There are also iguanas, in two types: some that are colored and others that are dark, in coffee color. The two types of iguanas are there, mixed with sea lions. They make nests on the same beach, sunbathe on the same rocks, but separate when they go to eat: the colorful ones eat cacti, and the dark, seaweed that is in the water. These dark iguanas are the only ones on the planet that, not only swim, but also dive to search for algae, as they can last a long time underwater. Their nasal passages can close impermeably and also have thick nictitating membranes, such as those found in many birds, cats and sharks.

Where did these marine iguanas come from? Evidently, terrestrial. And how did this happen? Terrestrial iguanas also came from the continent, where there are closely related species. When they arrived in the Galapagos, they did two things: they either kept their diet, their niche, or they changed their diet and, in doing so, transformed their ontogenic niche. Why did some iguanas decide to eat seaweed? It is difficult to know which contingencies intervened in this. It is not easy to imagine a situation in which the availability was only of algae and not of cacti, because in no part of the islands is that seen. Land iguanas also eat seaweed, eventually, but they don’t like it; they also swim, they don’t like it, but they swim; do not dive, but swim.

This is interesting: terrestrial iguanas have the optional possibility of swimming and eating algae, just as it is optional for human beings to dive. Human beings have already performed free dives at a depth of 120m, as if they were a dolphin. There are eighty million years of separation between dolphins; marine cetaceans are related to ungulates, and humans are more related to rodents. At no time have human beings been in the water, in their phylogenetic history, like mammals; however, they retained the optional possibility of diving at 120m. The plasticity hidden in an egg is very large and very conserved. And as we discussed earlier, on ontogenesis and epigenesis, this ancestral terrestrial iguana egg makes its history, not because there is a pre-formation for it to live on earth, but because there is a systemic conservation of this relational history between the living being and its world .

The question now is: what happens if this history of relationships changes? If systemic conservation begins to conserve another organism / world relationship, a separation of these strains will inevitably occur. Thus, for example, a change in conduct that is conserved transgenerationally, in a systemic manner, will result in the separation of lineages. This is what I believe happened in the Galapagos: the central change must have been changing the diet, and then other things that could be learned varied.

When you change what was preserved, other things can change there. If what I am conserving is changed, plasticity is released to change, that is, it will always vary around what is conserved. So, any change that amplifies, that facilitates, that reinforces, that deepens this way of life, will be channeled, co-opted. Because what is preserved is the reference for stabilizing change. This occurs systemically, so that, in the history of diving, the land iguana becomes the marine iguana, and the changes that will occur with it will reinforce this new way of life. So, what happens when, as in the case of iguanas, history begins to preserve another epigenetic path? There is an egg that arises from the plasticity of the ancestral, normative egg, but that follows a story that is outside the epigenetic space of the ancestral egg. The tree of epigenetic possibilities of the new egg is similar to the tree of possibilities of the ancestral egg. The organism / world relationship is what limits the possible changes (Figure 10).

Figure 10  Phylogenesis

 That is why we make this statement, which seems critical, that the total genotype follows the epigenetic realization of the phenotype in history, because the ontogenic phenotype is what acts as a reference for the changes that occur in the genotype. The total genotype is part of the realization of this epigenetic history and must be such as to allow its realization. This separates the two strains until both become independent. The new always appears, however, as a possible change in the relationship that is maintained. Phylogenesis is a drift in which there is a change in what is conserved in the ontogenic drift.

Relevant changes in phylogenesis are not mappable in the genome. There are endless examples of this. And it doesn’t have to be any other way. I think the genome is one of the most conserved aspects of the structure, if not the most conserved. And this is rightly expected: few changes, or many neutral changes – which is what is happening. I think the most important thing is the way of living, this way of meeting the organism with its environment, the way the niche is built by the organism.

In a way, these ideas come a little closer to Lamarck in the sense that it is the individual living being who builds the niche in his way of life; but, at the same time, they move away from Lamarck because they do not require somatic effects on the germ line. This may or may not happen. This is the transgenerational conservation of a change in the ontogenic phenotype and not the inheritance of an acquired trait. In fact, this discussion of somatic and germinal lines only makes sense after Weismann divides between ontogeny and phylogeny (Figure 5). Darwin argued, in principle, that there were acquired characters and that they could have a somatic fixation; but the relevance that is given today to what is called lamarquism, exists only because of the separation between ontogeny and phylogeny. We prefer to see phylogeny as a concatenation of several ontogenies. Furthermore, what I am exposing, in operational terms, does not require any finalist argument. As we have seen before, teleology is something that arises only when we confuse processes with the results that these processes generate and invoke the future to explain the present – as in the case of pointing out an organism adapting to the world.

Imagine this situation: the egg of the first chicken was not a chicken egg, but lived a chicken life and resulted in a chicken. It was not a chicken that laid that egg: it was an ancestor of the chicken. And that chicken that emerged historically from a non-chicken, as a possibility, lays a chicken egg. This egg that the first chicken lays, either makes possible the new relationships established in living, or does not allow them. If it makes them possible, it will be incorporated into this systemic cycle; if he doesn’t allow them, it lives like the ancestor or lives like something else. The systemic limitation of this relationship acts as a limit to the variability that appears in the reproductive cycle.

What is the final consequence of this? The chicken has a chicken egg, because the chicken story operated as a reference for the changes in the non-chicken egg (the ancestral egg). In any case, the changes in the eggs were changes with the conservation of the “chicken”. What ends up happening is that the egg is different from the ancestral egg. And where does this chicken egg come from? It emerges from the story of “chicken”.

See an interesting example of how these things can happen, of how plasticity explodes at any moment and may or may not be relevant, depending on whether or not it is incorporated into a new way of living. The plasticity in the way of development that makes mammals possible is also present in other amniotics. There are two ways to “placentar”. There are marsupials and mammals. The marsupials form a very fragile placenta derived from the membrane that surrounds the embryonic attachments, the amnion – the semipermeable membrane that allows the exchange of gases in the reptile egg and in the chicken egg, and in the animals that have an egg in shell; oviparous amniotics. The eggs of these animals exchange gases with the atmosphere through the shell through the amniotic membrane, which is one of the first elements to form in the egg. In eutheric mammals, like us, there is a chorionic placenta, derived from another embryonic attachment: the chorion, which admits implantation in the uterus, the formation of this vascular plexus, the deep implantation, so to speak, and the formation of this nourishing complex that includes the umbilical cord and the placenta. The marsupials form a semi-placenta derived from the amnion, which is very fragile as a placenta, with the consequence that the animal, which is in the reproductive tract of the female for a very short period, is expelled from the female and ends its development in the marsupial pouch where it binds to a breast.

Where did the chorion come from? Without chorionic placentas, there can be no euterium mammals, like us, with intrauterine development. There is a group of marsupials, very derivative, that are small, arboreal, with big ears, that have chorionic placentas. That is, from the amniotic egg, one can have amniotic or chorionic placentas, and this will depend on the way of life of the animal that derives from the ancestor. It is very likely that the ancestral mammal emerged from an egg, that it has a well-developed amnion and that settled in the “mammalian” first, and acquired the chorion later. In the same way, this chorionic placenta is incorporated into the way of life of an amniotic marsupial much later, at another time in history.

I believe that we can say that the way of life is the reference for changes and for the conservation of novelty in the total genotype. And if we say that, we are in the presence of a systemic situation that explains both conservation and change. In this way, once a new systemic situation is established to be preserved, everything in the structure will change around the conservation of this new relationship. The iguana can swim, not usually, but it can swim; and you start eating seaweed, you don’t usually eat it, but you start eating it. But, if you start to swim and maintain the behavior of eating seaweed by swimming, everything that can change around the conservation of this new habit will change, until the new iguana appears.

And what I am saying is different from what Goldschimidt said with his metaphor of “hopeful monsters”, because, according to him, these promising monsters would be something that suddenly appears in a lineage. I think that, as the different possibilities are always arising from the ancestor, the new egg is not a “monster”, but an optional possibility of the ancestor; it is not something that suddenly appears out of nowhere, but as a consequence of the organism / world relationship. It is a possible change from the ancestor; therefore, it does not come out of nowhere. Also, you see, Biology does not follow laws, rules or principles. There is no reason to be just one thing. For this reason, the modes of reproduction are so many and so variable; almost impossible to systematize them.

I will return to the point of formation of the bone shell of the turtles to make me clearer about that point. Scott Gilbert and collaborators (2001) have investigated the process by which this unique turtle structure originates. What happens during the embryonic development of these animals is that there are two cell lines that change sides, that is, a differentiated migration that results in this curious carapace. What is peculiar to turtles? The scapular waist is inside the rib cage. As a consequence, the vertebrae form ingrained in the dermis, which calcify to form the bony carapace. Now, notice, if this happens to a chick, a “monster” appears; but if this happens to a turtle, a beautiful animal appears. This can happen, it is in the phenotypic plasticity of that ontogeny; but there are situations in which what happens is incorporated and conserved, as in the history of turtles.

I wanted to take you to another landscape, again; let’s go to Lake Victoria, in Africa, allow me. This lake underwent a period of drought, giving rise to several smaller lakes, and then refilled in a recent period on a geological scale of time. There is a characteristic fauna in each lake, with extremely precise ecological relations between them; there are some animals that are preyed upon by others, some that are herbivores, others that are parasitic, in short, there are many species in a lake. We look at another lake, seeing how many different shapes there are, and find the same shapes as the first lake, or very similar. How can a shape match arise between two distinct lakes? It was investigated, then, about the genetic proximity of the species, and, to everyone’s huge surprise, it turns out that, in each lake, the species are all related to each other and genetically distant from the species of the other lake, despite having shapes that appear to be the same in the two lakes (MEYER et al., 1990). Similar and corresponding species in the different lakes were expected to be derived from each other. However, as a result, in a lake, the fish are all descendants of a single ancestor and, in the other, they are descendants of another ancestor. And, in both cases, there was an explosion of variability, of a lot of forms of new species. All this in less than 12 thousand years! A ridiculous amount of time! That is to say, in an ancestral cichlid fish, there were, say, fifty possible species; fifty different ways of life that will express themselves as different, independent; that will become independent in the course of just twelve thousand years.

Something similar to the genus Anolis (Family Iguanidae) occurs in the Caribbean. This is a genus of lizard abundant throughout Central America. In Africa, they are “islands” of lakes, but in the Caribbean, they are islands. This has been studied for some time. On each island, the Anolis have six distinct morphospecies – on each of these islands, there is a lizard that lives in the litter, another on the leaves, the sand lizard, the tree lizard, the trunk lizard and the foliage lizard. And they are all distinct from each other, but very similar to the lizards of the same morphospecies that inhabit other islands. Thus, as in the case of fish from Lake Victoria, it was thought that a lizard from each particular morphology had appeared on the first island, and that it migrated to all the others. I mean, it was assumed that there was an ancestral lizard, that lived on the trunk, that initially appeared on one island and then migrated to all the others. It turns out, however, that lizards are genetically closer among animals on the same island, and not among animals with the same morphology. This means that each lizard has six morphospecies regardless of which one has colonized the island. And that happens quickly. A hurricane can occur and sweep the island, and soon the process is repeated. Morphospecies are formed again. From the egg of an ancestral lizard that colonizes the island, six distinct shapes emerge, each one living in a particular way. It turns out that lizards were raised in cages to see what was going on. If they put a board for the lizard to grow, a lizard would grow from the trunk; if they put sticks, a lizard was born from the branches, with very long paws. It emerged as a possibility of the same ancestor, according to the way of living (LOSOS et al., 1999; 2001; LEAL et al., 2002).

What these examples profoundly show us is that an apparently trivial separation in the way of life ends up having tremendous consequences. It is true that we can ask what are the circumstances that made it possible to conserve a new way of life, in each particular situation, but the important thing is the change in this relationship of encounter between the animal and its environment.

Let me tell you the case of Periophthalmus (Gobiidae) fish, which have the characteristic of being like amphibians. These are fish that live in mangrove trees. They have large frontal eyes; their pectoral fins are transformed into real paws. And these fish climb trees, have movements similar to chameleons and are carnivores. They feed on insects and even small mangrove crabs. Unlike other fish, which do not support the terrestrial environment for a long time, these animals in question are extremely active outside the water. For this reason, they are also popularly called “mud-jumping fish” (from English mudskipper). The way they hunt is very curious: they stay out of the water and, when they see an insect nearby, spit out a stream of water; the insect falls, and they dive back and eat it. Where do these curious fish come from? They have their origin in an archer fish (Toxotes sp.), which does something similar, but from the water-air interface, from where they project a jet of water on insects that fall and are eaten (both are of the Order Perciformes).

The mud-jumping fish breathe out of the water because the branchial arches keep the water in the mouth; and they also have semipermeable skin, like other fish, being able to breathe through the skin and recirculating the water in the oral cavity, while keeping the cap closed. So, the first stage is when the animal is in the water. The second, an animal is on a rock. Can it be there? Of course, it can be there. In the third, he is already accommodated; and again we have the invasion of land by sea creatures, a new origin for amphibians. If we look closely, we will see very clearly that all these great transitions of animal life that are so impressive to us – the conquest of the terrestrial environment, as well as that of the skies – happened in the same way: with the preservation of a relationship that was an optional possibility of the ancestor. The lungs were invented by fish, still in the water; feathers and all these other essential characteristics for flight were still invented in theropod dinosaurs.

You see, the evolution of the shape does not follow the molecular change, which does not initially lead to a morphological change. I say this because they are independent structural dimensions and, therefore, can change independently of each other. It is the same situation that we discussed about fish and its nervous system, the domain of physiology and conduct. There should not be an intersection between them because, in the end, the realization of the system as a whole is a condition of existence for changes in components. Then the system drags its components, and the changes that will be admitted to the structural configuration of the system are those that are compatible with the way of life. It therefore occurs that the phenotype drags the genotype. Neutral mutations, for example, if they do nothing, remain there. Molecules change, generally, in a neutral way, or, in general, in a deleterious way, because a point change, of a molecule, regardless of any other systemic change, or has no consequence (that is, it is neutral), or probably has a disaggregating implication.

Now, if I compare the enzymatic activity of a bacterium with that of a eukaryotic cell, I will find that they are approximately 70% identical, that is, the invention of molecules is very old, much before the invention of animals. The appearance of biological molecules and biological metabolism is very conserved; it appeared previously and as a condition of possibility of the history of organization of metacellulars and plants.

The main animal development genes are present and act on organisms that have no development at all. Look at the treatment that has been given to hox genes, among others called “master genes” of development. It is often said that the Pax-6 gene is the eye gene, right? It turns out that the Pax-6 gene is expressed in the human cortex. And form an eye there in the cortex? No. Genes are like tiles; they are processes of maintenance of the protein network, and, as such, will participate in many different dynamics, at different times in history. Of course, they are part of the dynamics of development and also participate in dynamics that are already metabolic in organisms that have no development in the conservation of an already developed characteristic. As an example, we can mention the genes that have to do with segmentation, such as these Pax genes, which are normally expressed in the already differentiated cortex.

So, the gene is like a tool, it is an architectural problem, not the drift; this is the architecture of the building. That is the question: genes are conserved, and it is easy to understand why. When you change a DNA sequence that will be transcribed in such a way that the transcription will have an effect on enzymatic kinetics, it is more likely that the animal will die, because we are dealing with very specific changes. It is more plausible to think that organisms survive when many things change together, congruently. Point mutations are deleterious in almost all cases, as changes in a system occur through systemic changes.

There is an interesting problem in experiments with the cultivation of epithelial cells, through which teeth appear in the epithelium of the cornea of birds, animals that have had no teeth for the last seventy million years. And the absence of teeth seems to define these animals. Has the genetics necessary to produce teeth been suppressed? Certainly not. Birds can form teeth; the tissue interactions that result in the recruitment of the mechanism for the formation of teeth can occur. If we put this epithelium in contact with another epithelium, in an appropriate way, we make teeth emerge from a chick’s cornea (KOLLAR; FISHER, 1980). Yes, but – you can say – this results only from laboratory manipulation. But, look at the carnivores, their dentures, the distribution of teeth that is characteristic of all animals of that Order. Carnivores have a diastema, a toothless stretch that separates canines from molars. This characteristic is very conserved; so, we would soon think that there must be a gene behind it. There is, however, a very derived feline, the lynx, which does not have this diastema. And this is not an ancestral animal, it is very derived, that is, we have the same situation as the experiment of producing bird teeth from mammalian choroidal epithelia, and here we are not in the laboratory, we are in nature. We can assume that there would be a “carnivore diastema gene”, but there is this derived feline that expresses this ancestral characteristic: a denture without the diastema. This means that the genetics involved in the formation of the diastema should be there, since the radiation of this group of animals from the branch of ungulates – carnivores emerged from a branch of ungulates.

We can cite one or two more examples, similar to this one, but it is not about genes, but about a change in history, in the systemic relationship. And genes will follow this, because the story that follows is the same as that of the organism, of which they are components; and, as such, their condition of existence is organic existence. And, in turn, the condition of the organism’s existence is the realization of its niche.

I want to give you one last example. I don’t want to convince you of anything, but at least show that it is possible to ask these questions in a way that contemplates history. There is a place in Chile that is very rich in marine fauna: there are penguins, sea otters, dolphins, sea lions. There is an island separated from the mainland by a channel with a stream of very cold water and rich in organic substrates, so that many fish accumulate there. And penguins like to eat these fish. The mammals that live there – sea lions, otters and dolphins – eat the same fish and it would seem that they live in the same place. And they are very different animals. What do these animals look like? They don’t look like each other. Dolphins look like other cetaceans. Sea lions resemble bears and, in fact, are bears. And otters resemble ferrets. What makes them different is the way they got there. Otters are more like their ancestor than the other animals they live with and share the same diet in the same place. So the sea lion is a bear in the water; the otter is a ferret in the water. They change when their niche changes, they change in a way that is consistent with changing the niche, but in a way that can change according to the way of life from which it emerged. So, the otter is a possibility of the ferret, but it is not of the bear; the sea lion is a possibility of the bear, that is, I cannot reach the sea lion from otters; I will arrive through the bear. And where is the sea lion bear? This is called a polar bear.

They arrived there being different animals and, then, they are what they can be in that place they arrived at, that is, the way they arrived determines what they can be. A thousand times a ferret is thrown into the water, a thousand times an otter will appear, never a bear. That is what I mean. And that is what we find with this strange adaptation. The sea lion is perfectly adapted to be what it is. Each animal is totally and perfectly adapted to be what it is, because it is the result of a story in which it emerged, and it could not be otherwise. We can learn by looking at nature and thinking about it.

And, finally, notice that we went on here talking about organisms and their histories, and I did not mention natural selection at any time. I said a lot about ontogenesis and phylogenesis, and I didn’t have to mention it. It was not necessary.

References

• GILBERT, S. F. Morphogenesis of the turtle shell: the development of a novel structure in tetrapod evolution. Evolution & Development, n. 3, p. 47- 58, 2001.
• KOLLAR, E. J.; FISHER, E. C. Tooth induction in chick epithelium: expression of quiescent genes for enamel synthesis. Science, n. 207, p. 993- 995, 1980.
• LEAL, M.; KNOX, A. K.; LOSOS, J. B. Lack of convergence in aquatic Anolis lizard. Evolution, v. 56, p. 785-791, 2002.
• LOSOS, J. B. et al. Evolutionary implications of the phenotypic plasticity in the hindlimb of the lizard Anolis sagrei. Evolution, v. 54, p. 301-305, 1999.
• LOSOS, J. B. et al. Experimental studies of adaptive differentiation in Bahamian Anolis lizards. Genetica, v. 112, p. 399-415, 2001.
• MATURANA, H. R.; MPODOZIS, J. Origen de las especies por medio de la deriva natural. O la diversificación de los lineajes a través de la conservación y cambio de los fenótipos ontogênicos. Santiago: Museo de Historia Natural, 1992.
• MATURANA, H. R.; MPODOZIS, J. The origin of species by means of natural drift, Revista Chilena de Historia Natural, n. 73, p. 261-310, 2000.
• MEYER, A. et al. Monophyletic origin of Lake Victoria cichlid fishes suggested by mitochondrial DNA sequences. Nature, v. 347, p. 550-553, 1990.

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CHAPTER 2 – AN IMMUNE SYSTEM, AFTER ALL

Chapter 2.1 – The Gordian knot between Biology and Immunology 

Gustavo Campos Ramos

It is obvious to all of us that the sun also rises every day. Even Hemingway has made it a romance. We see that it systematically parades through our horizons, in the same direction; and then turns its back on us for a couple of hours. However, today, we know very well that this is not true, and, as evident as the path of the Sun seems to us, we are the ones who gravitate towards it. Even so, as Darcy Ribeiro (1979) said: “it took a lot of cunning and wit to show that dawn and dusk are bullshit”. I mention this because Biology is full of obvious things that surround us, but about which we are not concerned with questioning. They are, therefore, certainties like the Sun, which is given and does not seem to lack a more detailed explanation of why it arises like this, in this way, and not another. In a way, this is what neo-Darwinism represents for Biology: a certainty that is no longer revisited – “the Theory of Evolution”, as if it were the only way of thinking. However, there is no more discussion about the validity of neo-Darwinian premises in contemporary biology. It goes straight to the unfolding of this so omnipresent and so obvious thing in which everyone is entangled.

It follows, then, that this neo-Darwinian certainty is rooted in the most solid pillars of any biological discipline, from molecular to ecological. This is, for example, the conceptual framework for Immunology, a discipline that, despite being usually seen as a field of Medical Sciences, had its foundations built in close association with the great discussions of Biology. Jerne, Talmage and Burnet introduced “selectionist” ideas to explain immunological phenomena at a time when neo-Darwinism was consolidated as the main biological theory.

This extraordinary conceptual link between Biology and Immunology causes changes in the way of seeing Biology that imply changes in Immunology. Conversely, serious changes in immunology can only occur together with the rediscussion of their biological premises. Thus, this moment of biological reflections, which we have the opportunity to enjoy here, provides an ideal opportunity for Immunology to reconnect with such debates and, then, to revisit its certainties built in approximation with Biology.

It is very important to point this out because, on one occasion, I was told that the difficulty of reaching a consensus in Evolutionary Biology is due to the fact that ideas are discussed there, while in these applied experimental areas results and methods – concrete data – are discussed. But, you see, these “concrete” experimental data invariably depend on previous ideas – it is from them that questions are formulated and ways of answering them are defined. Thinking is something you do with your hands, as Mpodozis says. Realize that, for example, in order to study acetylcholine antagonist drugs, I need to accept the concept that there are proteins in the cell membranes, which I imagine operating according to the key-lock model, etc. So, in the case of applied disciplines, such as Immunology or Pharmacology, which claim to be purely experimental, this relationship with Biology is more problematic, in the sense that these “concepts behind the data” are often implicit. They are accepted without further reflection.

The proposal that I am going to present attempts to explain these concepts hidden behind the answers, or rather, I will question the Gordian knot that unites defensive immunology with neo-Darwinian biology. This biological contextualization of immunology is, therefore, an invitation to the reader to pay attention, to doubt the obvious that surrounds us; that is, in a way, I won’t say anything that we don’t already know.

Natural selection is the answer to what kind of question?

I once received a short text from Vaz, with a series of seemingly inverted questions, such as that on that topic. It was a very amusing manuscript because what it inverted, in fact, was our position as observers, and forced us to reflect on the nature of the questions we have been asking. This is the type of attitude that underscores the premises that we accept a priori. I mean, when I am in front of a flying bird, with its wings and feathers, and I accept that the explanation for this is that natural selection generated it optimized for the flight, in this way, what else am I saying?

The answer of the Synthetic Theory tells us clearly that there is something there that we call biological information, something very important that must be transmitted to the next generation and that explains the inheritance. In fact, this neo-Darwinian explanation goes further and tells us that this information responsible for inheritance is specified in the genotypes of organisms, and that the phenotype is the simple expression of these genotypes (Figure 5, p. 64). Of course, a careful neo-Darwinian discourse is not that simple, and politely tells us that the medium also influences the phenotype, etc. But, in the end, it is always placed in terms of environmental influences on the pattern of gene transcription, in tips for activating alternative genetic programs, which only reinforces this position centered on genes, so unanimous in this perspective. Accepting that this is the case, it is logical to conclude that, in this view, evolution is the result of genotypic changes over time in a given population. And then, population genetics emerges as the main tool in the study of evolution; that is, in this way, evolution is seen as a population and genetic problem, or rather, of genotypic frequencies.

Another important premise embedded in neo-Darwinism is that variability (always genetic) appears at random and, then, extrinsic factors to the organism select (filter) phenotypes “more adapted” to a given environment, and, therefore, also select genotypes – what really matters in that way of seeing.

Understand what we are saying here: to accept that there is this environmental filter that we call selection, we must admit that there is something, a noun, a very special particle, that contains the form and the inheritance and can be selected. After all, it is a selection of hereditary particles that this theory addresses. But, mind you, if we accept that there may be such a molecule that contains the adult form, then we are being pre-formationists, as has been extensively discussed in previous chapters (e.g. Chapter 1.3). And there is one more complication in this story, because, for this to work, it is necessary to agree that this selectable genetic information is also contained in particles that are independent of each other – the organism must be disjointed. In other words, the organism cannot be a system; therefore, following this explanatory path, we would add many tithes in a fraction (e.g. 0.9999), in the confidence that we are getting somewhere, but this tithing would never become a unit (1).

Completing the pillars that support this view, it is also pointed out that this whole process must be slow, gradual and optimizing, since it selects the most adapted phenotypes. And, finally, I still emphasize that this encounter between the organism and its environment seems to be unidirectional, in the sense that the destiny of the organism is determined through environmental filters, while the environment seems to be indifferent to the presence of the organisms. (For a critical view about the history and foundations of the Synthesis of neo-Darwinism, see GOULD, 2002).

These are premises that we accept when we choose an adaptationist discourse, that is, “selection” is the answer to a question that admits the existence of particles of information that are transmissible; that the organism can be disjointed in independent structures; and that English market laws, such as competition and the Malthusian struggle for survival, are operative in the natural world. As I mentioned earlier, we are not always aware of how many arguments we passively accept when, innocently, we say that natural selection built the wings for the hawk to fly.

Obviously, we are not here questioning Darwin’s importance in the history and development of Biology. We agree, of course, with what this naturalist pointed out about common ancestry, that is, that all species are derived from one another. However, the direction that Biology took to explain how this situation originates (through a modern synthesis) is what seems to me an impoverishing way of dealing with the natural world.

Immune defense is the answer to what kind of question?

Similar to the reflection we have on Evolutionary Biology, what can we say when we invert our question and point to our own immunological questions?

Since its origin, at the end of the 19^th century, Immunology arose from the idea that the disease represents a form of struggle between species of living beings, between the cells of the host and those of the pathogen. Thus, the concept of immunological defense as a mechanism was quickly created. This is a somewhat obvious development of the notion that competition would be the law of nature – a strong Darwinian legacy. And once it is accepted that defense is the function of the immune system, an instrument of competition, it becomes inevitable that the processes that take place in the immune system are described in a warlike language, e.g. “defense arsenal” and antibodies (SILVERSTEIN, 2003). Over time, this notion of antibodies, for Immunology, became, more or less, as a replica of the notion of genes for Biology. Something said, initially, in metaphorical terms, to say – “as if they were antibodies …”, which later became the personification of processes. Vaccine efficiency, autoimmunity and allergy have all been described in terms of the presence / absence of a specific antibody. This is exactly the same as saying that the innate behavior, the size of the egret’s beak and the color of the flamingos were expressions of a particular nucleotide sequence.

Finally, I think that the culmination of this intimate embrace between selectionist biology and defensive immunology came about through Burnet’s Theory of Clonal Selection in 1957. Note that this occurred shortly after the publication of Watson and Crick’s article on the structure of nucleic acids, which would explain Biology. In short, what Burnet proposed was that the lymphocytes generated a repertoire of antibodies through random mutations, and that they then expanded, like clones, according to antigenic contacts, that is, they were selected by factors extrinsic to the organism, like magic wands guiding lymphocytes. Clonal Selection and Natural Selection are two versions of the same idea, as the very name of these theories makes a point of telling us.

Darwinian medicine

It is interesting that this biological insertion in clinical urgency does not stop there. Recently, and with considerable delay, a neo-Darwinian proposal has also emerged for Medicine. In 1994, a book was published entitled Why We Get Sick: The New Science of Darwinian Medicine, written by a physician, Randolph Nessa, and a famous evolutionist, George C. Williams. These authors try to explain medical problems by Darwinian mechanisms. The question asked, in this perspective, is about the causes of diseases, near and remote. How did the gene, hormone or bacteria, which appear as causes close to the disease, appear evolutionarily? That question – How do we get sick? – it is important for us in this compilation of texts, because Nelson Vaz has something very strong and coherent to say on this topic (Chapter 2.4). The answer that Nessa and Williams (1994) propose is that we can fall ill due to restrictions imposed by natural selection. A useful gene, for example, can be inherited in association with another deleterious one; or that organisms are actually shaped for reproductive success and not to resist disease. In this way, the genes that guarantee reproductive success can carry with them other genes that determine illness. With that, we can conclude that, in the view that they defend, genes (always seen as causes) are selected, not individuals. In short, a vision centered on genes and adaptation. And again, I try to put the question in reverse: what kind of question is this Darwinian medicine an answer to? When asking for a genetic cause, it is accepted that not only inheritance, but diseases also have specific causes as well as a particle that contains them; for example, that anxiety, alcoholism and depression are genetically determined behaviors, not systemically and historically constructed. Furthermore, it is admitted that there is this arms race between the host and his aggressors, and that we have survived submerged in this aversive world.

The Gordian knot

There is, therefore, a mutual validation of neo-Darwinian ideas with conceptions of defensive immunology, to which now also a neo-Darwinian medicine is associated. This is the node of questions and answers that we want to revisit, because, in all these cases, the way of asking hides the organism and its historical development (Figure 11).

Figure 11  The Gordian knot between neo-Darwinian biology and defensive immunology

 

Back to the natural world

Now that we have explained these premises that are accepted in the neo-Darwinian discourse and in Burnetian Immunology, I would like to discuss the consistency of these premises today. The sequence of this text is, therefore, an invitation to return to a couple of situations that we encounter in the natural world.

In this sense, what comes to me first is Kimura’s Neutralist Theory (1979). This theory finds that most molecular changes (genotypic) are neutral from a phenotypic point of view. But there is a serious problem here, because Kimura was completely misunderstood and today we only discuss neutralism when selection pressures are not important. However, in my view, the big implication of what Kimura shows us is to decouple what goes on in molecular dynamics with what goes on with the form and way of living of organisms – these are things that we describe in different domains. The comparison of mutation rates in the alpha and beta chains of hemoglobins between humans and Elasmobrachii (sharks and rays) (KIMURA, 1979) shows, for example, that both the frequencies and the types of mutations in these proteins are the same in humans. and sharks, who live in completely different environments. This indicates that, in this case, the selective pressures of the environment did not guide and did not specify the molecular changes in these populations. And, more importantly, we are comparing an organism that has a very conserved form – sharks have lived there for approximately four hundred million years – with the human species, which is very recent and has had some important changes in shape in its recent history. Now, if the form is explained as being related to the genotype, that is, if macroevolution is an unfolding of microevolution, how would these two animal species that present similar mutation rates present such a different rate of change? It doesn’t make sense, they are separate domains. Again, I would like to reinforce this point, because that is not how Kimura’s arguments are currently treated: I think that the great importance of these findings is to explain the decoupling between molecular dynamics – what happens with genes – and the origin of form. This is very serious. But, at the same time, Kimura also does not explain to us what it is and how the form is generated; it deals only with molecules. From his ideas, the notion of Genetic Drift arose, a spontaneous and blind flow of nucleotide substitution rates, not directed by environmental filters – something that was received with discredit in the 1970s, and that today is experimentally demonstrable as being more of a rule than exception. Even so, it is important to emphasize that it remains, however, a molecular, genetic explanation, which, although important, has nothing to do with the problem of the origin of form and the way of life of living beings in this natural world. For this reason, too, we must not confuse Genetic Drift with Natural Drift, proposed by Maturana and Mpodozis, something much more general, in short, a fundamental theory about living.

If we keep an eye on the examples that the natural world offers us, we find other serious problems with the current Synthetic Theory. There is a very interesting quote from Darwin in the Origin of Species in which he says that “if they showed a complex organ that was not built slowly and gradually, my theory would have no defense”. We look, however, around us and do not find it happening. Could anyone mention seeing a bird with a rudimentary wing, or a fish with a hinged half mouth? Now, if evolution were a slow and gradual process (a continuum of changes), then we should expect to find an abundance of intermediate forms in the fossil record, but this is not the case. Darwin was aware of this, but he believed that the fossil record was incomplete, and that, in time, these intermediate forms should be found. Today we have fossils of microorganisms and even urine from dinosaurs, but we still do not have records of these possible intermediate forms. Gould and Eldredge (1972), in turn, admitted that the fossil record was not incomplete and proposed a hypothetical hypothesis: that evolution would follow a pattern with long periods of little change in shape (stasis), interrupted by sudden periods of changes in form. And it is curious to think that even in these long periods of stasis, as in these last four hundred million years in which sharks retained their shape, the rates of molecular change remained high, as we learned from Kimura. Just as an example, we can look at the history of jaw formation on which there is a very rich fossil record. If we look at representatives of live fish, then we see that there are either lampreys, absolutely without an articulated jaw, or sharks and other fish already with a fully articulated jaw. Likewise, we only find fossil representatives at these two extremes. Realize that if evolution had been slow and gradual, then there should have been an animal with a rudimentary jaw, which, due to its usefulness, would have survived longer. Their descendants, all with this characteristic, would then occupy a niche with more success until an organism with an even more articulated jaw appeared at random, which would gradually improve until it forms what we see today. However, this is not what we find in the fossil record. Furthermore, it is difficult to imagine the adaptive advantage of a 5% rudiment of the mandible or the wing.

These two theories proposed in the 1970s, Neutralism (by Kimura) and Punctuated Equilibrium (by Gould and Eldredge), were configured as the first serious criticisms of neo-Darwinism. In addition to these initial proposals, today we see the resumption of an important discussion, at the same time vast and more delicate, about the idea of biological information contained in genes. Based on a systemic perspective, as we discussed at this meeting, we do not admit the existence of biological information contained in genes and in any other particular component of the organism. Even the term “information” is inappropriate if we reflect critically on the subject. I highlight in this context the book by Evelyn Fox Keller (2000): The century of the gene, which discusses very well how to define a gene and what it does, pointing out the inconveniences of considering it as a source of information for the cell, disconnected from the processes of cell dynamics.

There is an amazing example in this regard. We all know how refined our knowledge in neuroanatomy is. We can obtain these detailed atlases that deal with the brain specializations of different animals and that even allow us to perform stereotaxic surgeries to introduce an electrode in a very specific region of the brain of these animals. We can do this because all animals of the same species will have this same general brain organization. But it is not asked how this situation is established. Why is my area of Broca always formed more or less in the same place? Genes? Is there a destination map in my egg cell that, since fertilization, has plans for this area of Broca to form in my brain? We don’t know much about it, because we generally take it for granted and don’t ask ourselves how these things are built. There are, however, studies that demonstrate that these neuro-anatomical specializations are the result of asymmetric stimulation during the development of the nervous system. The lateralization of the anterior portion of the brain of certain birds is, for example, extremely dependent on their prenatal sensory experience. What happens is that, in the most advanced stages of their development, the pigeon embryos are positioned in the egg in such a way that their left eye and ear remain occluded by the yolk sac, one of its embryonic attachments. For this reason, only your right eye is exposed to the light that passes through the eggshell. Likewise, during this period, these embryos listen only through their right ear. And, from this prenatal asymmetry, a series of hemispheric specializations in the brain of these birds results, including visual discrimination, spatial orientation and several other motor asymmetries (LICKLITER; HONEYCUTT, 2003). And, therefore, we can perform stereotactic surgeries on these animals, following our neuroanatomy atlases with confidence. Evidently, if I were a geneticist and wanted to ask myself, legitimately, how genes are part of this, I would find there in the right eye of these birds a gene expression that is distinct from the other eye that remains hidden. It is important to know this too, but, can we say that genes inform the cerebral location of an area specialized in light perception? No, because that would disregard the cellular interactions between neurons that are activated during sensory perception, it disregards the behavior of the animal inside an egg, and all these important relationships for the realization of its history. It is difficult to accept an explanation centered on genes when the history of organisms is taken seriously.

There are many uncomfortable points when we reflect on these premises of official Biology. But one last point that I would like to draw your attention to concerns this division of the organism into structures that can be selected independently. This prevents us from making any systemic description of Biology. That is, we saw Mpodozis talking about how the lashes of an epithelium rotate on a pole of the embryo, and as a result, the heart is formed on the left, the liver on the right, the spleen, the stomach; in short, many things become asymmetrical due to a ciliary beat that transports substances that act asymmetrically on cells on both sides of the embryo. We cannot select a specific feature without it having systemic repercussions. I like Mpodozis’ phrase a lot: “Changes in a system only happen in a systemic way”. This is not redundant, it is trivial and inescapable. We cannot disrespect that. If we did, and accepted that the organism can be totally disjointed, then it is no longer a system, because we put it out of Biology! And we do something similar in the case of Immunology when we disjoint the lymphocytes and study clonal expansions, as if that doesn’t affect the physiology of other lymphocytes. We analyzed how a lymphocyte interacts with an antigen in isolation, but we cannot say what these lymphocytes all do in our healthy organism. It is really scary when we see these things hidden behind our certainties.

No history, no organisms

Many times, when they hear us talking about neo-Darwinism, they accuse us of oversimplifying the problem, that the vision is not that finalist, and that even the genetic program is not taken so seriously – in short, that we are shooting a dead horse. But on the first page of the book by Nessa and Williams (1994), it is written: “If a DNA strand can encode the plans for the adult organism, why are we unable to regenerate a lost finger?”; that is, it is in fact said that the DNA strand has the plans to build the adult individual. Everything that happens in between, developmental biology, everything that is there is just a transit to the adult state, an adult-centered biology. What’s wrong with that view? Well, if there is a plan to specify the adult, I am not going to study the intermediate steps – the development – which come to be seen as evanescent passages up to the adult.

In the same way, also in Immunology, the lymphocyte system, being between chance and selection, is no longer something important, because, on the one hand, chance prevents a historical approach to how the organism is constructed at each moment; on the other hand, by assuming a stimulus / response view in which external pressures determine the course of changes and do so when acting on units (clones) isolated from each other. We put the system inside a black box that prevents us from understanding the processes that generate what we observe. Proof of this is that the term physiology is virtually absent from any description of immunological activity.

So, in these particular cases, we are talking about a Biology that has no organisms or history; an immune system that does not seem to have a physiology, and a finalist medicine in search of specific causes for getting sick. It is an uncomfortable knot that we pointed out, but which I think we already have enough elements to untie.

Nouns hide verbs

Maturana says that “Behind each noun, a verb is hidden”. And that is what I mean in this criticism. When I ask for a verb, I ask for a “generating mechanism” of what is happening; if I ask for the noun, I ask for an “explanatory principle”, which, in fact, does not explain anything. The answer to a question addressed to the verb contains the noun; but the answer to a question addressed to the noun does not contain verbs. As biologists and immunologists, we want to understand processes.

When I ask for “inheritance”, for the noun “inheritance”, I ask for a structure, for something that will ultimately be reduced to the structure of DNA. Likewise, when I ask about the specific cause of an autoimmune disease, I find a specific antibody in response. But has DNA solved the problem of understanding the transgenerational conservation of biological characteristics? Furthermore, has the antibody solved the problem of becoming ill?

If we change the question, however, to “How do these characteristics remain from one generation to another?”, or “How do we get sick?”, then we are asking for verbs, and we will look for processes. So, I will be concerned with understanding how organisms are built again with each generation. This is a much more comprehensive way of asking. I believe that what Vaz has been trying to tell us for so many years, in the specific case of Immunology, is that we should exchange the question about the “specific cause” of the disease, for the “operation of a conservative physiology of the immune system”, as well as an “immanent theory” of falling ill.

So, our proposals involve an option for other explanations, imply exchanging “explanatory principles” for a search for processes that contain the “generating mechanism” of what we want to explain. These two ways of asking – by verbs or by nouns – take us in completely different directions. You cannot think about transgenerational conservation without thinking about a process. I cannot think about the stability of immune processes triggered by the ingestion of a protein, such as the lack of an antibody molecule. We are not looking for a molecule; there is not a particle of historical preservation, it does not make sense to think so. We have to think about processes, as Mpodozis said so much. Verbs demand processes. The idea, therefore, is to make this perception of the differences between ways of seeing appear in our language.

The question of function, for example, will always direct us to formulate an answer that is an explanatory principle, never a generative mechanism. Therefore, we do not like this defensive immunology that tries to elucidate the supposed defense function of lymphocytes, doing this in a way that is foreign to its physiology.

I will try to be more clear. You see, how curious: in the earliest periods of embryonic development, the embryo performs its gas exchange through a simple diffusion; until, after a certain size, this is no longer possible and then it is observed that there is now a blood circulation and a beating heart. So, this is enough to say that the heart arose to maintain oxygenation – that is its function. But, contrary to what was expected from a functionalist perspective, the heart begins to beat much earlier and not from the moment the embryo reaches that size that makes diffusion impossible (BURGGREN et al., 2002).

I mean, in the early stages of development, the little animal is there spreading and beating its heart. The heart is surgically removed; so, what’s up? The embryo continues to live and oxygenate its tissues. The heart appears in a context independent of this oxygen supply function; then it does so because, of course, it was a possibility of this ontogeny. It does not arise to perform this function, which we attribute to the heart in adults. And in what web of relationships is the heart involved at that moment? With the formation of evaginations of the digestive tract, with the curvature of the brain in the form of an arc and with the anterior posture of the embryo as a whole (WADDINGTON, 1937). Realize, however, that the important thing is that, in order to understand how the heart appears in the embryo, we need to understand its context of relationships and its history, not its purpose (its function). For this reason, the functionalist explanation does not serve us. We don’t have to accept a finalist perspective that sees the embryo as a miniaturized adult.

The same thing has happened in the history of the immune system. We have to understand what the lymphocytes are doing in the operation of the organism, as part of it, and not try to describe how the system performs the function that we attribute to it. Evidently, as an observer looking at a machine, I can assign function to the parts. And when I deal with living beings, I can also assign a function to an autopoietic machine, in the sense that they are participating in the maintenance of that organization. The function is somewhat legitimate as part of a comment on the machine description. Of course, when I see the result of its operation, I can say that the heart has a utility in pumping blood, and, if I want to call this utility a function, I can; but still, this is just a comment I make when looking at the process result. The problem is to place this function and utility as if they were references for the operation of the heart. The heart pumps blood due to its history of construction and not because of the usefulness of the result generated by its performance. But the neo-Darwinian question is always: “What is the function of this?”; for this reason, he is unable to detach himself from a finalism that is so uncomfortable to us. The neo-Darwinian approach follows a scientific research program based on function, which is not the logic that the organism follows.

I believe it is clear that, at this point of the reflections, we realize that metaphors such as immune defense are like the daily bullshit of the Sun, which every day pretends to be born and set.

Back to the organism

Finally, I would like to glimpse something distant that could replace this Gordian knot that we have just undone. I do this because I believe that this relationship between Immunology and Biology must be preserved, albeit in different ways, as Biology is renewed. This subject about new directions that we can follow will certainly be the main focus of what Nelson Vaz will propose in the sequence of this section.

So, let’s say I cut off a salamander’s arm; I will have an animal there with limited movement and way of life. Perhaps we said that this being now has a life that is restricted. This is only for some time, as these animals, curiously, are able to completely regenerate their lost limbs. But let’s say that we want to understand this situation very deeply; so we are going to study microscopically the tissue structure at the injured site. In doing so, we find migration of blood cells, phagocytic macrophages, activation of the coagulation cascade and other cascades of plasma proteins; in short, all these very common things about inflammation happen. Is this salamander sick, with less flexibility? I believe that many people would say yes when they see her walking crooked while not fully regenerating; or, upon finding, under a microscope, the tissue with active macrophages.

Let us also say that I am a naturalist and that I am interested in understanding this regeneration in different animal groups; so I decide to study if this same situation happens, if I cut one of the arms of a starfish. It does not have lymphocytes, of course, but in the same way, I will see phenomena of amebooid cell migration, phagocytosis, extracellular matrix degradation, and many things that are similar to what happens in a classic inflammatory process. Meanwhile, this animal continues to live with a missing piece, restricted. The question again arises: Is this starfish sick? Inflamed? It is hard to say; perhaps many would say yes, but we could undoubtedly study these inflammatory aspects there in that lesion.

The curious difference in the case of the starfish is that, depending on the way I do the section, the smaller piece of the arm that has been cut off can “regenerate” an entire animal again. It is like a kind of vegetative reproduction. The interesting thing is that the animal does it through the same classic processes of “innate immunity”, which take place in the healing of the other lesion. Imagine how amazing it is, because we are talking about an entire individual being born from a piece of the arm! The salamander does not do this, it is not assembled from a small sectioned arm. But, then, what’s going on in that piece of starfish? It is, at the same time, an inflammatory / scarring process and an ontogenetic / reproductive process, which results in the construction of an entire new individual (MORGAN, 1901). I mean, I take off a piece of that starfish, look at it and say that it is incomplete, limited, healing; but I turn and look now at the smaller piece that remains and say that a new individual is forming – I speak in reproduction. Note, however, that in both cases, similar processes are going on. The difference there is our position as observers; in both situations, there is the preservation of a living, an ontogenetic process. What I mean is that generating the form, keeping it generated and generating it again (regenerating) are problems of the same nature; and inflammation is inserted, therefore, in this scenario as something close to Developmental Biology. Finally, as a more biological and less technological / pharmaceutical problem, although its clinical applications are later very relevant.

There is another noteworthy situation. I refer to a squid that lives in the marine environment, lives with a bacterial species (Vibrio fischeri) and then a couple of things are triggered. When interacting with this bacterium, the squid’s ontogeny changes and the formation of a new tissue begins. You can even identify specific molecular patterns of the bacterial wall that interact with receptors in the cells of these squid. In this new tissue, a microenvironment is created that allows these bacteria to accumulate. In this new environment, these same bacteria have, however, a new way of living, and become chemiluminescent. In the establishment of these relationships, the squid gains a flashlight, can hunt and make sexual cuts, while these vibrions, in turn, can multiply free from predators. We speak, therefore, about this event in terms of a symbiotic association for the formation of a luminescent organ so important for the living of these squids (KIMBELL; MCFALL-NGAI, 2003).

However, if we are going to study the human microbiota and its relationship with our organism, we see that the same classes of molecules of the bacterial cell wall trigger the formation of similar morphogenetic processes, which result in the formation of lymphoid tissues associated with our mucous membranes, and better structuring of intestinal microvilli. But, particularly in these cases, we study this process, which is analogous to that of squid, in medical terms, of antimicrobial defense, and we do not ask ourselves how it is associated with the human way of life and the construction of our tissues. Why do we treat these cases so differently?

As Mpodozis and Botelho explained earlier, the distinction between instinctive behavior and learning is that, in the case of learning, we know the history that generated that conduct; in the case of instinct, we are ignorant of this story. But the processes that generate both situations are the same. The difference between an immune / inflammatory process and a continuous activity of generation and regeneration of the organism, although it is a legitimate distinction, is something that occurs in the domain of our observation, and not something that is contained as a special factor in the phenomena that we describe.

What I mean is that we can exchange the question “How does the organism defend itself?” for another: “How does the immune system participate in this continuous process in which the organism makes the organism? The Immunology that results from this encounter with a systemic and historical biology goes beyond the simple search for antibodies and vaccines; and, therefore, it is not focused on this defensive view. It is part of the study of living, of conserving, of building and of rebuilding organisms.

References

• BURGGREN, W.; CROSSLEY, D. A. Comparative cardiovascular development: improving the conceptual framework. Comparative Biochemistry and Physiology – Part A: Molecular & Integrative Physiology, n. 132, p. 661-674, 2002.
• BURNET, F. M. A modification of Jerne’s theory of antibody production using the concept of clonal selection. Australian Journal of Science, 20, p. 67-69, 1957.
• KELLER, E. F. The century of the gene. Cambridge: Harvard University Press, 2000.
• KIMURA, M. The neutral theory of molecular evolution. Cambridge University Press, 1983.
• GOULD, S. J.; LEWONTIN, R. The Spandrels of San Marco and the Panglossian Paradigm: A critique of the adaptationist programme. Proceedings of the Royal Society of London; n. 205B, p. 581-598, 1979.
• GOULD, S. J.; ELDREDGE, N. Punctuated equilibrium comes of age. Nature, n. 18, p. 223-227, 1993.
• GOULD, S. J. The structure of evolutionary theory. Cambridge: Harvard University Press, 2002.
• KIMBELL, J. R.; MCFALL-NGAI, M. The Squid-Vibrio Symbioses: From Demes to Genes. Integrative and comparative biology, n. 43, p. 254-260, 2003.
• LICKLITER, R.; HONEYCUTT, H. Developmental Dynamics: Toward a Biologically Plausible Evolutionary Psychology. Psychological Bulletin, 129, p. 819-835, 2003.
• MORGAN, T. H. Regeneration. New York: Macmillan Co., 1901.
• NESSE, R. M.; WILLIAMS, G. C. Why We Get Sick: The new science of darwinian medicine. New York: Vintage, 1994.
• RIBEIRO, D. Sobre o óbvio/ensaios insólitos. Porto Alegre: L&PM, 1979.
• SILVERSTEIN, A. M. Darwinism and Immunology: from Metchinikoff to Burnet. Nature Immunology, n. 4, p. 3-6, 2003.
• WADDINGTON, C. The dependence of head curvature on the development of the heart in the chick embryo. Journal of Experimental Biology, 14, p.229-231, 1937.

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Chapter 2.2 – Inflammation as a phenomenon of animal development

Gustavo Campos Ramos

The ability to maintain and restore tissue integrity is a central aspect of the life of all organisms, and the ways in which tissue structure and organization is restored after injury can be as diverse as animal life forms. A starfish larva, for example, reacts to the insertion of a thorn with an intense migration of phagocytic mesenchymal cells (METCHNIKOFF, 1891). In turn, an amphioxus responds to the same type of challenge through extracellular digestion promoted by the secretion of enzymes from its epithelial cells (SILVA et al., 1994). A salamander that had an amputated limb is capable of entirely reconstructing a new functional limb, while the other amphibians replace it with fibrous tissue (MESCHER; NEFF, 2006). And even when we restrict the problem of tissue repair to a very particular animal group – e.g. mammals – it is necessary to recognize that, even so, the paths through which tissues are assembled and reassembled are very varied. For example, a deep cut in the skin of an adult human usually triggers an acute inflammation followed by a fibroproliferative process, with scarring; the same type of injury pronounced on a human fetus can trigger processes that result in the formation of a new skin tissue (regeneration) identical to the original (COWIN et al., 1998).

Regardless, however, of the particularities of the tissue reconstruction process in the most diverse groups of animals, it is quite intuitive to accept that regeneration and inflammation are closely related processes. Certainly, the events that underlie the formation of a new amphibian tail and the inflammation that occurs as a result of a myocardial injury in a rat injected with high doses of isoproterenol, are phenomena of a similar nature. Why, however, is the regeneration problem recognized as a form-building problem, while inflammation is not? Why is regeneration a biological problem and inflammation an exclusively medical problem? I believe that the answer to these questions lies in the history of the characterization of these phenomena and stems from the way of treating these themes experimentally.

Origins of inflammatory certainties

The starting point of the study of inflammation most widely accepted by the scientific community is the description of cardinal signs – rubor et calor cum tumor et dolor – carried out by the Roman physician Celso approximately two thousand years ago (VIRCHOW, 1852; SPECTOR; WILLOUGHBY, 1963; ROCHA E SILVA; GARCIA LEME, 1972). This expression, even today, is widely reproduced and can be considered representative of the common sense that we have around this idea. What is not usually mentioned, however, is that, when manifesting in these terms, Celso saw inflammation simply as a set of clinical symptoms and not as a phenomenon itself. When Aristotle coined the term “development” to refer to a flowering of the shape of a chicken embryo, he designated a process of living. But the “inflammation” was not the designation of a process of living, but a set of signs resulting from some process that remained ignored. Thus, under the burden of representing no more than a mere clinical symptom, “inflammation” remained treated as an idea that did not require further explanation. For a long time, pathologists involved with this matter were content to list more and more details about what happened in a diseased organism or in an injured tissue, without worrying about defining the ideas that the concept of inflammation encompassed (ZIEGLER, 1889 ; RECKLINGHAUSEN, 1883 apud METCHNIKOFF, 1891). For this reason, in the 19^th century, it was not uncommon to find scientists who advocated the end of the use of the term “inflammation” (THOMA, 1886 apud METCHNIKOFF, 1891). Even Virchow, the German pathologist who proposed a fifth inflammatory cardinal sign – funtio laesa – was categorical in stating that inflammation was not a “real entity” (VIRCHOW, 1852), but a term that brought together a series of phenomena so different , which would be better treated separately.

From Celso until the mid-19^th century, it can be said that the lack of a biological / organismic context that would unify the various descriptions of the reactions of an injured tissue generated a gap in the concept of inflammation, and, more seriously, isolated the approach to this phenomenon, which was strictly medical, of other biological phenomena of a very similar nature. Animal regeneration, for example, was discovered in the 18^th century and was experiencing a period of very rich debates about the origin of the animal form (DINSMORE, 1991) at the same time when inflammation was reborn under the eyes of cellular pathology. However, there was no attempt to bring these ideas together, as I discuss below. This approach did not happen because, while regeneration was seen as a form-building phenomenon, until the end of the 19^th century, inflammation did not even have the condition of a biological phenomenon.

An important landmark of the change in this perspective was the description, by Julius Cohnheim, about the passage of white blood cells through the capillaries to the inflamed tissue – diapedesis. For Cohnheim, this was no longer a mere histological description of what happened when he got sick, but a mechanism for generating cardinal signs of inflammation. In describing the changes in capillary conformation, with a consequent increase in plasma leakage and the passage of blood cells that will compose the pus corpuscles, Cohnheim was proposing how the symptoms described by Celso were generated. Thus, the idea of Julius Cohnheim, that “the cause of the inflammation lies in the vessels”, was a proposal that unified several subsidiary problems around a unique phenomenon and that made the inflammation, finally, an organic process. Within this perspective, inflammation was clearly an event of falling ill; i.e., to fully understand it, it was necessary to elucidate the cellular mechanisms of becoming ill.

There is no doubt that this was a fundamental step in the history of the study of inflammation. It is likely that this was the real starting point for the study of inflammation. There are, however, two important limitations to Cohnheim’s position. First, the inflammatory processes were exclusively pathological mechanisms, without a physiological counterpart. When placing vascular injury as an ontological assumption for inflammation reactions, it was not possible to explain how these events participated in healthy living. Inflammation was configured as a phenomenon without physiology and without the premise of having one. This was a completely unique situation, because when we deal with any other organic system, we want to understand its physiological functioning, before explaining the emergence of a pathological state. We would not explain the cardiac arrhythmia by being ignorant of the electrical physiology of the heart, but we do not have the same reservation when we study inflammation in the exclusively pathological context. With very few exceptions (VAZ; VARELA, 1978; VAZ et al., 2006), the term “physiology” is not mentioned in the immunoinflammatory jargon, which lacks clear attention about the organism.

The second limitation in Cohnheim’s initiative to explain the origin of cardinal signs from vascular events was that it was a valid truth for a very restricted group of animals: a bird or a mammal would present something that could fit the explanation of cellular pathology. After all, if vascular injury was a sine qua non condition for the onset of inflammatory dynamics, what would happen when an animal lacking a circulatory system suffered tissue injury? How are all the other animals reassembled?

Therefore, at the same time that Cohnheim’s explanation represented an advance in the cellular pathology of inflammation, it was necessary to admit that reactions to an injury in a mammal were something exceptional, a phenomenon distinct from the repair mechanisms of all other animals. We still lacked a more general view on the construction and reorganization of the biological form. And only when this problem, hitherto exclusively pathological, was addressed by other disciplines, these limitations were seen. Metchnikoff, a Russian embryologist, was important in this transformation.

Metchnikoff was interested in the formation of new embryonic structures during animal development and investigated the involvement of a group of migratory and phagocytic mesenchymal cells in these phenomena. According to him, the understanding of phagocytosis was important because this event could be observed in all animals, including the simplest and most primitive forms (except amphioxus!). When comparing phagocytosis in different groups of animals, Metchnikoff observed that phagocytes could eventually ingest not only nutritious substances but also foreign particles and “invading” microorganisms (TAUBER; CHERNYAK, 1991).

This last observation, in particular, acquired great relevance because it occurred at the time when Pasteur proposed that diseases were caused by specific germs, and when Darwin’s work placed the struggle for survival as the most relevant problem in Biology. With the proposal that phagocytosis was a “defense mechanism” against the aggressions of the environment, Metchnikoff united the most important medical and biological theories of the 19^th century (1891). And since phagocytosis was an event common to all animals, Metchnikoff understood that this would be the primum movens of inflammation. In this way, the inflammation went from a human pathological reaction to a healthy animal “defense” response (TAUBER; CHERNYAK, 1991).

It was Metchnikoff who created the notion of a “defensive function” for inflammatory activity, which has become central to the modern concept of immunity. When Cohnheim described diapedesis, a defensive connotation was not yet embedded in this process. But I would point out that this idea of “defensive function” created by Metchnikoff should not be naively accepted, as we usually see it when using the notion of function. He was aware that the same process, which now resulted in defense, also participated in the embryonic and physiological processes of generation of the organism. For example, Metchnikoff himself had previously described that phagocytosis participates in the tail regression of an amphibian tadpole. Thus, Metchnikoff referred to a “physiological inflammation”, and, for him, the construction of the organism was a much bigger problem, which preceded its “defense”. In Metchnikoff, inflammation and immunity were situations subsidiary to animal development, particular situations in the construction of metacellular “harmony”. Thus, the opportunity was open for inflammation to be seen also in its physiological aspects (TAUBER, 2003).

Without giving up the important advances in pathology, Metchnikoff (1891) bypassed the limitations of Cohnheim’s proposal and created an idea of great biological value. However, Metchnikoff’s only idea effectively accepted by his peers was the defensive connotation of phagocytic activity (and usually with a naivety that he himself did not have). All of his other considerations about the physiology of building animal form were quickly ignored. The recently founded Immunology has grown as a discipline much more concerned with understanding the pathogen / host relationship than understanding any other generative or physiological aspect of immunoinflammatory activity.

In this way, the two main schools of approach to the inflammatory theme were created: the tradition of Pathology, which saw inflammation as a reaction of the disease, and the immunological school, which saw it as a defense response.

A third, much more recent tradition of research on inflammation is the pharmacological approach. With the birth of the pharmaceutical industry, also at the end of the 19^th century, the race for the development of new methods of intervention in inflammatory processes became important. Thus, while pathologists described the organism’s reactions to illness and immunologists studied the recognition of foreign materials, pharmacologists looked for ways to intervene in such events. In this context, there is an event in the study of inflammation that deserves to be highlighted: the invention of the model of paw edema induced by carrageenan, by researchers from the pharmaceutical industry Merck (WINTER et al., 1962).

During the first half of the 20^th century, approaches to developing anti-inflammatory drugs were overly laborious and slow. In general, to characterize a possible anti-inflammatory agent, it was necessary to study inflammation as part of the reconstruction of injured tissue. These models were expensive, with protocols that lasted for several weeks.

In 1962, a group of Merck researchers developed a model that finally complied with all the premises desired by the interests of those who want to quickly develop a product – edema induced by carrageenan in the rodent’s paw. This protocol could be carried out entirely in four hours, it required only a single administration of the drug to be tested, and its principle was based on the measurement of one of Celso’s cardinal signs – edema. Finally, for heuristic reasons, the industry tried to create a model that separated the cardinal signs of inflammation from the complicated processes of tissue reconstruction: inflammation was merely a clinical symptom again.

The practical success of this idea was immediate and in less than a year, Merck developed indomethacin, a drug that still serves as a reference for the development of new anti-inflammatory agents. The other industries quickly reproduced this model and, in the same decade, dozens of new anti-inflammatory agents successfully entered the market. The curious thing is that this experimental protocol was also widely accepted in the academic environment and became widely used in basic research, as if it were an adequate model for understanding the phenomenon of inflammation. This had very serious consequences because, by co-opting a protocol that had been developed with the aim of making pharmacological development simple for a research model on the inflammatory theme, inflammation again ceased to be a phenomenon of living and became a cardinal sign again, as it was in Roman medicine, two thousand years ago.

Origins of certainties in regenerative biology

The initial characterization of the animal regeneration process is attributed to Adam Trembley, when studying cuts in polyps of a hydra (DINSMORE, 1991). At the time, it was unclear whether the hydra polyps were animals or plants, so Trembley decided to section them because he knew that only plants were capable of regeneration. Then, after this procedure, it was observed that the hydras were able to recompose their lost parts and thus promote a complete tissue repair with the rescue of the status quo ante – a feature, until then, exclusively vegetal. However, all other observations about the life cycle of these organisms led to the conclusion that they were really animals. Then, with enormous surprise, the possibility of animal regeneration was recognized.

There is, however, something even more special about this Trembley finding: since the two halves of a hydra were able to promote perfect tissue repair (regeneration), this situation was, at the same time, a process of tissue recomposition and animal reproduction. Thus, the discovery of regeneration was also the discovery of a new form of asexual reproduction. This exceptional situation meant that animal regeneration was immediately seen not only as an injury repair phenomenon, but as an event in animal development, linked to the problem of reproduction and form generation. And this Trembley finding occurred at a favorable moment, at the height of the embryological debate about the origin of form: the debate between pre-formationism and 18^th century epigenesis. Therefore, it is not surprising that regeneration started to be studied by embryologists (DINSMORE, 1991).

Thus, in contrast to inflammation, which in this period was not even treated as a phenomenon with its own identity, animal regeneration was already born within a framework of well-defined biological ideas, occupying the central position in an arena of rich debates. The theories of regeneration were put side by side with the theories of embryonic development and metamorphosis – i.e., regeneration has always been seen as a physiological phenomenon of animal development.

Inflammation as a developmental biology phenomenon

Certainly, the study of inflammation today has spread its borders across several areas of scientific knowledge, and this phenomenon could hardly be addressed within the limits of a single discipline. This plurality is not only desirable but necessary. My particular interest in commenting on the emergence of three main schools of study of inflammation – pathological, immunological and pharmacological – is not merely historical, but to show that it is the context in which our observations are made that defines the nature of the phenomenon that distinguishes itself. As it has been contemplated throughout history, inflammation has emerged both as a symptom and as a mechanism. It is not intended to deny here the importance of such medical and industrial approaches to the theme, but at least to show that it is also legitimate to treat the theme from a biological and physiological perspective. For this reason, in what follows, I strive, not to discuss the definition of inflammation, but to show what contours it can take when glimpsed from the context of Developmental Biology.

At the outset, I say that, although inflammation and regeneration are phenomena that arose from very different interests, it makes no sense to study them separately in the current biological landscape. Although legitimate, medical concerns about inflammation should not obscure the fact that, in addition to clinical symptoms and magic bullets, inflammation becomes a process of living. Thus, there is an immediate need to reconcile this theme with the development and construction of the animal form. More than defense, the events we describe in inflammation are processes of building the organism. This can be illustrated with countless examples, but here I will present only one, which I consider quite clear.

Salamanders can regenerate their eyes, including delicate fabrics, such as the retina, iris and lenses. The surgical removal of lenses from the salamander eye triggers changes in pigmented epithelial cells on the pupillary margin of the iris, which are able to enter the cell cycle and transdifferentiate into a new lens (TSONIS et al., 2004). In a recently developed experimental model (KANAO; MIYACHI, 2006), it was characterized that events typically described as immunoinflammatory participate in the process of genesis of a new ocular lens. When the lenses are damaged with a needle through the cornea, they autophagy degenerate a process mediated by dendritic cells and the elimination of the damaged lenses gives rise to the regeneration of new tissue from the dorsal margin of the iris. These authors observed that the transfer of dendritic cells, isolated from the ocular tissue of animals in the process of autophagy / regeneration, to naïve animals (with untouched eyes), was able to promote genesis of a second lens, despite the absence of lesions. Furthermore, if the animals that adoptively receive these activated dendritic cells were previously splenectomized, this generative effect would be inhibited. Therefore, the formation of new ocular tissues critically depends on processes that take place in a lymphoid organ such as the spleen. This is an example of complex tissue genesis mediated by immunoinflammatory mechanisms, thus illustrating the generative aspect of inflammatory activity.

It is even intuitive, after hearing about it, to admit that the problems addressed by embryologists and pathologists are phenomena of the same nature. However, it is necessary to go further and recognize that the consequences of this approach are not trivial. The genesis of the biological form does not end with birth, nor does it begin again with becoming ill. But, in order to see it this way, it is necessary that living be seen in its incessant dynamic of transformations, like a Heraclitus fire, or better, in a historical way as previously woven by Mpodozis. To understand inflammation, it is necessary to understand the organism in its dynamic life of assembling / maintaining it, every day. For this, it is necessary to escape from animal models where there are landmarks that seem so solid: birth and illness. In this context, I believe that hydras are an interesting animal model for weaving bridges to unite the work of embryologists and pathologists.

Inflammation physiology – Genesis does not end with birth or start again with illness

An adult hydra polyp consists of two layers of epithelial cells, one derived from the endoderm and the other from the ectoderm, arranged to form a bilaminar tube around a gastric cavity. At the apical end of this tube, there is a head, where the oral opening is formed with tentacles, and at the other end there is a disk of cells responsible for the organism’s adhesion to the substrate. In addition to these two layers, these animals are also made up of a simple set of interstitial cells, which give rise to neurons, gonads and secretory cells (STEELE, 2002).

In a series of very elegant experiments, Campbell (1967) dyed the cells in different portions of this animal with dyes and followed the dynamics of tissue movement during the life of hydras. Their findings are impressive because, although these animals survive for many years maintaining the same body size, the movement of their tissues is incessant. Campbel (1967) found that, due to the incessant mitosis of the epithelial cells that make up hydras, all of its cells are constantly changing their position in relation to their axial axis. It is a dramatic dynamic, although invisible to our eyes when we observe them in natura. And it is impressive that, through these tissue movements, an epithelial cell belonging to the central column of the organism eventually reaches the end of the body, and then differentiates itself into specialized cells of the tentacle or basal disc (GALLIOT et al., 2006). The coordination of cell differentiation in hydras depends on their position in relation to the axial axis of the organism, however these positions are not constant. It is a situation of incredible phenotypic plasticity in which, sometimes a cell is in one context and acquires an identity, sometimes it is in another and it modifies its phenotype. The same goes for the cells of the interstitial compartment. For example, a secretory interstitial cell that is at a moment in a more medial portion of the anteroposterior axis of the animal, when it reaches the location of the head, it acquires a neuron phenotype (GALLIOT et al., 2006). The body remains preserved, but all components continue to change and reassemble throughout their life. As Mpodozis points out, this is a good example for understanding what is preserved in what changes.

We thought that the hydra was a sessile animal, of fixed size and shape, pale and without much grace, but now we see that an intense change underlies this constancy. The shape of these animals is absolutely preserved throughout their lives, and yet the mechanisms of generation and exchange are unceasing. How, from this whole change, is there a hydra that is so unique? When was this adult ready? This is an ideal example to blur the boundaries between embryology and pathology, because, in this case, it is difficult to determine when a “regeneration” begins, since in that organism the “generation” has never ceased.

When we escape animal models centered on the adult organism, we realize the second point to be seriously defended in this manuscript: the genesis of the form was never a variant relegated to a particular moment in the animal’s life cycle. The adult form is not something given, it is not a gift from our uterine past, but a daily process. This conserved generation of daily living is an aspect currently neglected, which is neither studied by the embryologist who finishes his study at birth, nor by the pathologist who begins his study with the disturbance of this conservation. I believe that both disciplines would gain by extrapolating their territories until they find themselves in the situation of healthy adult living. I believe that this has very serious consequences, as it is precisely the physiology of inflammation that allows us to contemplate the physiological counterpart of the processes we study in becoming ill.

A difficulty in accepting the approach I propose between animal development and inflammation, in a context that I call of the physiology of inflammation, is the poverty of our imagination about healthy living. It is not simply Medicine that does not require clear contemplation about the organism, it is Biology itself. Since Claude Bernard, we have been very fond of the notion of homeostasis, which tells us about a “constant state”. And this notion of a constant state of the organism derives from the premise that the harmony between the components is something given, that does not need to be explained.

In turn, Metchnikoff, who came from embryology and realized how complicated the construction of form was, strongly disagreed with Bernard (TAUBER, 1994; 2003). For him, at the beginning of ontogenesis, there was disharmony, so that harmony was delicately constructed and woven daily. He was concerned with construction processes. And, since Metchnikoff studied phagocytosis not only in the defensive context, but also in physiological situations such as the metamorphosis of the frog tadpole’s tail, he attributed the genesis of harmony to a process of “physiological inflammation” (TAUBER; CHERNYAK, 1991); pathological inflammation was subsidiary to the incessant physiological genesis.

An adequate view of healthy living should include tissue dynamics and the explicit notion that health or physiological normality is actively constructed. This notion is not explicit in the works of current descriptive pathology, but it was present in Metchnikoff as a legacy of his training as an embryologist. Thus, as unusual as it may seem to find the proposal to speak of “physiology of inflammation”, this is not an invention of the 21^st century.

Based on what was exposed, I maintain that the corollary of this essay can be summarized as follows: generating the form, keeping it generated and regenerating it are all related problems that deal with the most central question of Biology – the construction of organisms. It is necessary to recognize that, even in models centered on the adult organism, the dynamics of living never cease. It is not enough for us to understand how a heart is assembled embryonically, then how it can be reassembled after an injury; it is also necessary to understand how a heart remains a heart throughout its life. And it is precisely this physiological aspect of a daily dynamic of formation that makes it possible that the study of inflammation ceases to be merely a clinical symptom for which magic bullets must be invented and becomes a fundamental phenomenon for Biology.

Co-development – The relationship with the microbial world revisited

At first, the attempt to contextualize the study of inflammation in a developmental Biology perspective seems to neglect a central concern of this discipline: infectious diseases and the defense against them. Still, I insist that even the situation of establishing relations with the microbial world does not escape everything that has been argued so far. Even when it comes to the microbial theme, this proposal presented here finds great support in current biology.

Obviously, the importance of microbial presence cannot be overlooked, nor that of very serious infectious diseases. However, it is possible to approach these situations without seeing the organism as an entity that merely defends itself. The most important development biologist today, Scott Gilbert, has developed works considering an integration of animal development in an evolutionary and ecological context (Eco-Evo-Devo), giving great importance to the microorganism-immune system interface in the process of building the animal form. This is now one of the most serious and accepted approaches in modern developmental biology, and its main premise is the idea that “all development is co-development”. Thus, currently, it is understood in embryology that it is not only sufficient to elucidate details about the gastrulation of any animal, but it is also necessary to understand how its ontogeny integrates with the ontogenies of the organisms that surround it (GILBERT; EPEL, 2008).

In this context, the animal / microbial world relationship has been profoundly revisited under the guise of ontogenic bricolage, when these relationships are harmonious or disharmonious. And, according to authors, like Gilbert and McFall-Ngai, important references in the area, the immunoinflammatory activity starts to be seen as a relevant phenomenon in the integration of the living of different organisms and not merely as a defense system. At the other end of this approach between embryology and pathology, I emphasize that important researchers have also seriously considered that parasitology should be perceived more as a cohabitation problem than as a defense (LENZI; VANNIER-SANTOS, 2005).

The associations with bacteria – this co-development – have very curious nuances. McFall-Ngai’s group in Hawaii studies the symbiotic association of certain squids with bioluminescent bacteria (Vibrio fisheri) (e.g. KIMBELL; McFALL-NGAI, 2003; McFALL-NGAI, 2002; 2007). These squids, which are nighttime hunters, are born without bacteria and develop the rudiment of an organ that shelters them and starts to function as a “lantern”, which it uses in its hunts. This organ only develops fully in the presence of bacteria, and they, within the organ, also change phenotype. And what are the molecules involved in establishing these relationships between the two organisms? They are peptide-glycans, Toll-like receptors, phagocytes, expression of nitric oxide synthase; that is, components that participate in the reactions that we describe as inflammatory – a co-developmental situation.

Often, this example of squid is heard as picturesque and, when we consider the mice we work with again, we again use the bellicose – defense – metaphors to describe inflammation. But we wouldn’t have to do that. The development of the vascular network in the intestinal villi of a mouse raised in the absence of bacteria (germfree), for example, is greatly impaired (STAPPENBECK et al., 2002). This is certainly a question of co-development.

It is not a question of denying the occurrence of pathology in the relations with intestinal bacteria, but of seeing this in terms of deviations in development. We are not simply an organism that lives to defend itself from pathogenic germs, as it was conceived at the time when bacteriology appeared with Pasteur and that we did not have the tools to allow us to contemplate all this microbial diversity. In fact, current microbiology has been trying to make it clear to us that we have built a very delicate relationship with a diversity of microorganisms that is much greater than we supposed. We know, for example, that the native microbiota of rats and fish is quite different. But, when the native microbiota of fish in germfree rats, and that of rats in germfree fish (an exchange) is introduced, after a period of transformation, they restore floras that are close to the flora of their own species (RAWLS et al., 2006). So, the relationships between the organism and its microbiota are actively built, and the microorganisms that we carry with us are not mere sporadic passengers, but delicately cultivated cohabitants. The formation of an Actinobacteria biofilm in a particular region of a mammal’s digestive tract is an event as sophisticated as the formation of a neuronal network in a brain region. Thus, it is possible to see how immunoinflammatory activity takes part in the construction of living even when dealing with the establishment of relationships with microorganisms.

A recent genomic characterization of the microbiota associated with humans pointed to the existence of more than two thousand distinct species of commensal microorganisms, of which less than one hundred species are potentially pathogenic. Of course, it is important to understand the pathogenesis of these cases. However, it is necessary to recognize that an entire discipline dedicated exclusively to explaining infectious disease is a biology that deals with the exception (McFALL-NGAI, 2007).

Inflammation is an answer to what kind of question?

What has been exposed so far brings us to answer the following question: what kind of question is inflammation an answer to? I believe I can say that when an observer accepts the most plastic dimensions of the incessant dynamics of the composition of organisms, he realizes that it is precisely this enormous structural plasticity that makes the organization’s conservation possible. Obviously, such processes are more easily contemplated in situations in which the structure is disturbed due to injury or infection. In such cases, an observer may notice what changes around what is conserved as if it had a defensive or restorative connotation. And, at that moment, the idea of “inflammation” appears as a possible answer to these considerations.

There is no doubt that tissue plasticity includes processes that can accommodate disturbances and thereby result in defense or repair. But it is important to realize that such processes are results that an observer can distinguish and that, as such, they are part of a commentary on the mechanisms of living, and not part of the mechanism of living; they do not constitute explanations of the phenomenon of inflammation, nor do they operate as a reference for the changes in the organism. Furthermore, when the historical and systemic aspect of organisms is fully contemplated and living appears to us like a Heraclitus fire, it becomes evident that this same structural plasticity, which we treat from an inflammatory perspective in pathological situations, occurs incessantly throughout life, associated with many other events. Plasticity is not restricted to getting sick. When an observer accepts this, and raises the question of what remains and what changes in living (MPODOZIS, in press), inflammation comes close to developmental biology, and the concept of “physiology of inflammation” emerges as a possible way to refer to the organism in its living.

It seems to me quite difficult to separate the events that allow us to talk about inflammation from the other mechanisms that we observe during the generation of the form without this putting us in profound contradiction with current biological knowledge. In other words, inflammation = (in) formation.

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Chapter 2.3 – A brief history of immunological certainties

Nelson Monteiro Vaz

Immunology was not born from the study of plants and animals, but from the study of infectious diseases. Thus, it has a foot in Medicine and another in Biology. What I am going to say about Immunology has a lot to do with this dichotomy, this biomedical character. But, on this occasion, I will emphasize the relationships that I see between Immunology and the Biology of Knowledge and Language, a body of knowledge generated by Maturana, Varela, Mpodozis and collaborators. For me, this occasion is magnificent because, for the first time, I will be able to discuss my ideas about systemic immunology in a way intertwined with the texts of a genuinely systemic thinker, like Jorge Mpodozis.

Autopoiesis and Immunology

Humberto Maturana and Francisco Varela are best known for creating the concept of autopoiesis, but it is interesting to note that, in isolation, this conception does not add anything to what we already know; that is, it is not new that living beings are left to themselves, that they build and maintain themselves; that is, that they are autopoietic systems. This concept only acquires an important meaning – and then, very important – in a context artistically assembled for decades in which many other notions are part, such as the Biology of Knowing and Language.

My connection with these ideas started by chance when I met Francisco Varela and ended up offering him a position in the Department that I then headed at the National Asthma Center in Denver in the mid-1970s. We wrote a paper together (VAZ; VARELA, 1978 ) that explained, for the first time, a systemic notion of immunological activity, expressed in the title we created: Self and non-sense: an organism-centered approach to Immunology. The expression “self and non-self” explains the central concept in the dominant theory of Immunology, according to which immunological activity discriminates, separates between materials proper to the organism (self) and strangers (nonself), ignores the former and responds to the latter. “Self and non-sense”, in turn, represents what we wanted to put, that is, what happens (immunologically) must have some relevance to the organism, or it does not occur at all, it does not make immunological sense (“non-sense”), as we saw immunological activity as centered on the organism. This work was completely ignored.

Unfortunately, Francisco passed away in 2001, and his memory received several tributes. There are several records written and recorded in the literature and on the internet. Maturana and Varela’s (1987) best-known work is The Tree of Knowledge, in which the theory is briefly exposed. There are several pages on the internet dedicated to this topic; one, coordinated by Randall Whitaker, is quite extensive and up to date. There is also a Chilean network, coordinated by Alfredo Ruiz. Finally, the sources of information on the Biology of Knowledge and Language are abundant (see also <www.matriztica.org>).

Maturana became famous as a neurobiologist for his studies on amphibian vision. One of the best-known works of that time has a provocative title: “What the frog’s eye says to the frog’s brain” (LETTVIN et al., 1959), in which Maturana and collaborators mapped the distribution of four types of photoreceptors in the frog’s retina. Back in Chile, years later, Maturana tried to map chromatic receptors on the retina and, after a few years of fruitless experiments, came to the conclusion that this mapping could not be done. He then published a text on “A relativistic theory of color vision” (MATURANA et al., 1968), in which he made astonishing statements that, in my view, mark the beginning of his most important contributions to the so-called “cognitive sciences”, or the experimental study of knowing, how we can know anything and the biological bases of human understanding.

In this work, he shows that it is not possible to correlate the electrical activity of the retina with the wavelength of the radiation that affects it, but that it is perfectly possible to correlate the electrical activity of the retina with the name we give to the color projected on it. This is astonishing because the same color, say, green, can be produced by radiations of very different wavelengths; there is even the possibility of producing “green”, using a red and a white light source, in “colored shadows” experiments. Thus, whatever the wavelengths used, whenever the color perceived in the retina was called “green”, the recorded electrical activity was the same. This is a very serious conclusion because it inserts the observer, the experimenter, in the experimental fact. These are 1967 experiments, prior to the proposal for the concept of autopoiesis. And, for me, this fusion of physical-chemical data, objective, so to speak, with the experimenter’s personal activity, has relevance to what I will say later about immunological activity.

The intelligent design

We are all aware of the difficulties experienced by teachers of evolutionary theories in certain regions of the United States, due to objections raised by creationist convictions. I believe, however, that the need to replace an “intelligent project” (divine, transcendent) with an “intelligible process” extends far beyond these borders and has to do with what we have to discuss here. That an intelligence is attributed to natural processes appears, for example, in the title of the famous book written by the American physiologist Walter B. Cannon (1963): The wisdom of the body, in which it is demonstrated that the body has mechanisms, for example, bleeding control systems, which appear to be smart. Cannon was the originator of the concept of homeostasis, a modern version of the concept of internal environment, created by the famous French physiologist Claude Bernard, in the 19^th century: the idea that we, as organisms, and our cells, live in different worlds and that the world in which our cells live is highly regulated, much more constant. The concept that the body has a “wisdom”, which easily extends to endow it with an intentionality, is very present in Immunology.

Perhaps a more detailed view of the biological world, such as that available to us at the time of this meeting, will increase this temptation to attribute intelligence to biological processes, or, on the other hand, may lead us to new ways of seeing.

The versatility and ubiquity of living beings seems to us more and more amazing. Recently, it was found that each individual tree harbors, not only in its roots but on its leaves, a great complexity of microscopic beings, which are particular to each tree. After the RNA and DNA amplification methods became available, it was found that the microbial cultivation methods we use are extremely inefficient and only grow a tiny percentage of the sown living beings, about one percent of marine bacteria, for example. Our view of the breadth of the biological world, therefore, has expanded at least a hundred times. In the human oral mucosa alone, more than seven hundred bacterial species have been characterized, that is, we still do not know what world it is that we inhabit and what relationships are maintained between its inhabitants. Probably, if Pasteur were alive today, he would abandon the idea of aggressive germs as the cause of human diseases, as we now know that we live immersed in a living soup.

Gregory Bateson, another formidable thinker of the twentieth century, promoted discussions in his home, which were recorded and are available via the internet. One of these encounters, called neither supernatural, nor mechanical, is also very pertinent to what I mean, as we neither want to appeal to a purely mechanical vision, as if everything were taking place in a purely structural domain, nor do we intend to seek transcendent explanations, which will lend a hand resources external to our structure.

Generally, when we mention “cognitive” processes, it is thought that this brings up discussions about the brain, the nervous system, knowing it as an activity of animals and, also, that there is a hierarchy, and that we humans belong to the uppermost part. Maturana says that we cannot underestimate other living beings and talks about “non-neuronal” molecular nervous systems, present, for example, in protozoa, like parameciums, which are very sophisticated cells. What happens in such a living being is very complex and, operationally, comparable to what happens in metazoans or in the human organism.

Immunology is full of “cognitive” terms, such as the “recognition” of “foreign” materials, or immunological “memory”. What’s exciting about Immunology is that immunological activity seems to reconcile two incompatible properties: unlimited versatility and a particular (specific) way of dealing with each foreign material. How can this particular “strangeness” arise from each antigen? In biochemical terms, it was soon asked where the nucleic information required to synthesize so many different antibodies was. The act of qualifying certain molecules as “strange” and others as “familiar” is a cognitive act.

We have, then, two contrasting views: one, so to speak, “layman”, which attributes to the immunological activity, the immune body, a certain intelligence or intentionality, represented by this “strangeness” of certain materials; and another by immunologists, according to which these processes result from automatic, complex, but intelligible events. The intelligibility of Immunology is based on Evolutionary Theory, it is the same as the most radical readings of neo-Darwinism. According to this view, what happens depends on a source of variants that operates at random, coupled with a process in which these variants are selected by competition with each other, in which the fittest survive.

Immunological terminology itself is a constant source of cognitive connotations; the terms “immunity” or “antibody” refer to these ideas of “defense” or “protection”. And that is very understandable. Imagine that, in the 12^th century, Siena, Italy, was a city with one hundred thousand inhabitants, halfway between Rome and Paris, which in turn, at that time, had seventy thousand inhabitants. A bubonic plague epidemic destroyed eighty percent of the population in a few months, and the city has never regained its former heyday. It is, therefore, very natural for the international community to keep the memory of these tragic events and for there to be a dense terminology of meanings linked to these fears. And, when we abandon this justified view from a medical perspective and look for support in Biology, we find a strong association with neo-Darwinism, linked to a military, competitive, bloody view of the natural world, in which the most apt are selected – a scenario where this notion of wars and battles is also very present. As the miners would say, this corresponds to “taking your foot off the swing and putting your foot in the basket”.

A brief history of immunological certainties

Until the early 1950s, immunology was dominated by medical or biochemical interests and problems. After that time, when some vaccines were invented and the fundamental concepts were created, there was an immunochemical period, in which the biochemical nature of antigens and antibodies was intensively studied. Only in the 1950s, Immunology began to approach biological problems.

Like many trained people, Peter Medawar also worked on the care of people burned during the London bombings of World War II. During this period, he was impressed with what was happening with skin transplants from other people, performed on these patients, as an acute form of relief; grafts were invariably rejected after ten or twenty days, while autologous transplants were accepted. Medawar became convinced that the rejection was due to genetic differences. After the war was over, he proved that, in fact, this was true in experiments with rabbits.

Then something happened that would decide the future of Immunology. A veterinarian colleague needed a test capable of separating monozygotic bovine twins from dizygotic ones, and Medawar proposed to help him. He said that skin transplants between monozygotic twins would be accepted, while transplants between dizygotic twins would be rejected. He performed the experiments, and, to his surprise, the vast majority of transplants were accepted, even when the twins were evidently dizygotic, because one was male and the other female. The explanation lay in known facts about twin pregnancy. Often, in this situation, a cross circulation between the two fetuses is established, so that they are born as “chimeras”, that is, organisms containing cells from two individuals. The twins were therefore unable to reject mutual transplants.

Medawar decided to repeat these experiments on mice, of which isogenic strains were already available, that is, genetically homogeneous, and skin transplants within the same strain were not rejected. He injected mice of a given strain into the womb, on the eve of birth, with a suspension of cells from another strain. Several mice were born and grew up as if they were normal and, as adults, they were able to accept without rejecting a skin transplant from the donor strain, although they rejected in the usual time a skin transplant from a third, unrelated strain (Figure 12) .

Figure 12  Billingham, Brent & Medawar experiment, 1953.

In other experiments, Medawar and colleagues showed that this ability to accept without rejecting – they coined the term “tolerate” – an allogeneic transplant (from another lineage) was due to the absence of specific types of lymphocytes, as if the perinatal treatment had destroyed some lymphocytes and thereby making the animals specifically “tolerant” to certain types of transplants.

The concept of immunological tolerance duplicates the dimensions of the immunological problem, since the organism can not only be “immunized” against something, that is, increase its specific reactivity to a given material, but it can also be made “tolerant” to that material, that is, to behave in the opposite way to immunization, to decrease their specific response capacity. And, in this way, a dichotomy was created between immunizing and “tolerating”, similar to so many others that brought pseudoproblems to Biology, as discussed in previous essays. This extra dichotomy does not make sense and, in fact, it complicates something that should be treated very naturally – the stability of immune processes. Suppose we decided to describe self-inflicted injuries during seizures, such as tongue bites, as “psychomotor self-harm”. Suppose, in addition, we said that the physiological mechanism of mastication, which prevents the tongue from being bitten, involves the permanent inhibition of seizures, that is, “psychomotor self-harm”. Furthermore, let us call these neurological mechanisms for preserving the integrity of the tongue “neurotolerance”, meaning that the organism chooses not to bite its tongue as if it were food, so that it can remain in the mouth without being chewed. This absurd way of speaking is exactly the way in which immunologists explain why the immune system “tolerates” the presence of the body’s components, without destroying them. Later on, I intend to show a language that I think is simpler about these phenomena.

A second major step in the history of immunology occurs two years later, in 1955, when Niels Jerne proposes the first “selective” theory of immunology, entitled Theory of Natural Selection of Antibody Production, which explicitly adopts a neo-Darwinian view to explain immunological activity . He suggests that the organism spontaneously forms, in the absence of antigens, a wide variety of “natural antibodies”, in such a way that any foreign material that penetrates the body is very likely to react with some of these antibodies; and, in a way that Jerne does not explain well, these types of antibodies then have their production amplified. This would explain immunization and immune memory. In this view of Jerne, natural immunoglobulins pre-exist with the arrival of the antigen and cannot, therefore, be called “antibodies”, as they would only deserve this name after being amplified by antigenic contact. Jerne did not stop at length to explain the immune tolerance just described by Medawar, but his hypothesis is opposed to the immunological theories then in force, which had an “instructive” character, as if the antigen acted as a “template” for the production of specific antibodies.

Two years later, in 1957, in Australia, Burnet, a virologist, understands that the problem is not exactly in the “natural antibodies” suggested by Jerne, but in his cellular origin. Familiar with mouse lymphoid leukemias, in which each tumor is a clone, that is, a set of genetically identical cells, Burnet proposes that normal, non-neoplastic lymphocytes are also genetically (nucleically) distinct from each other and can expand and form clones. In addition, it states that each lymphocyte forms only one type, or a few types of antibodies; and that what the antigen selects when it penetrates the body is not simply antibodies, but the cells that produce them. The first version of the Clonal Selection Theory was created, which, to date, with several modifications, is the dominant theory in Immunology (Figure 13).

Figure 13  Theory of Clonal Selection (BURNET, 1959)

With the motto “a cell – an antibody”, the Clonal Selection Theory explains immunological immunization and memory, the fruit of clonal expansion, but also details immunological tolerance, the result of clonal inhibition. Burnet does, however, something else: he redefines a concept created by Paul Ehrlich, in the early 20^th century, called autotoxic horror, according to which the body prevents the production of antibodies against its own components, and says that autoreactive lymphocytes, capable of expanding and harming the organism, are “banned clones” and must be inhibited or destroyed in immature organisms before the immune system starts to function. With that, he creates the idea of “natural tolerance” or “self-tolerance”, according to which lymphocytes ignore the body’s components.

With these ideas, the Clonal Selection Theory creates the notion of “autoimmune diseases”, which would arise when some banned lymphocyte clones escape their ban. The concept was quickly accepted by Medicine, several clinical states were classified as “autoimmune” and many experimental models of inducing autoimmune aggression were created in animals. Nowadays, this has expanded to such an extent that even atherosclerosis, which is a very common disease in humans, is no longer the result of the deposit of fatty plaques on the vascular wall, to be an autoimmune disease, because there are T lymphocytes infiltrating the atherosclerotic plaques, and are believed to be important in their formation.

But, in Burnet’s view, lymphocytes cannot react to the body itself; therefore, they cannot also interact with other lymphocytes. And, since each lymphocyte forms a single type of antibody, the immune system cannot truly form a system: it is reduced to a set of clones isolated from each other and also from the organism of which they are part; they, so to speak, inhabit the organism and defend it from strange invaders, but are not, in fact, in it, but in a third position from which they can separate what is self (self) from what is strange (nonself)(TAUBER, 1994).

The prohibition of historical-systemic models

Thus, the Clonal Selection Theory and the way of seeing that it opens are impediments to a historical-systemic view of immunological activity. The conception cannot be historical, that is, described as a sequence of structural changes of a global nature, because the components of the system – the lymphocyte clones – as well as the specific products of the activation of these clones, such as antibodies, are generated in processes considered random. Chance would govern the emergence of clones after a random rearrangement of gene segments; again, chance would guide the activation of these clones through random encounters with foreign materials. One cannot tell the story of events at random and is therefore not expected to find any regularity, any characteristic conserved in the body’s immune activity, except the “memory” that triggers progressive clonal expansion, achieved, for example, by vaccination. Vision cannot be systemic, as autoreactivity is considered pathogenic, and this prohibits contact between lymphocytes and also lymphocytes with the organism of which they are part. As in Biology, in this traditional Immunology there can also be no systems and histories, that is, they are hidden by the usual way of asking questions in Burnetian Immunology.

It is important to note that the Clonal Selection Theory proposal, in its full original form (BURNET, 1959), preceded the characterization of T lymphocytes (MILLER, 1961) and the understanding that they are crucial elements in immunological activity (MITCHISON, 1959 ; CLAYTON, 2006). And that it also preceded, for a quarter of a century, the understanding that the activation of T lymphocytes, on which the activation of other lymphocytes depends, is subject to its interaction with peptides conjugated with MHC products in “presenting cells” (LANZAVECCHIA, 1985). In summary, clonal theory was proposed before the recognition that immunological activity is an expression of the result of interactions between lymphocytes – for example, between T and B lymphocytes – and between lymphocytes and other cellular components of the organism, such as, for example, dendritic cells that operate as “presenters”. Lymphocytes, therefore, act integrated with each other and with the organism to which they belong. It is strange to think that they have been conceived in another way.

But Immunology is not only valid, it is validated by neo-Darwinism. And changing the immunological theory implies antagonizing neo-Darwinism. Clonal selection is often used as an example of evolution by competition: the selection of the “most apt” lymphocytes by the antigen would show evolution in action during the life of a single organism. So, changing the way we view Immunology is not easy, because it involves confronting the neo-Darwinian ideas, and these are the most powerful in Biology.

We still have to face the problems brought by the medical view of immunological “defense”, with its “cognitive” metaphors (recognition, memory, etc.) that are not even examined as such. The immunological “defense” is a legitimate comment that we can make about the result of the organism’s interactions with infectious agents, but, as such, it belongs to our description, and not to the mechanism operating in the observed organism. In his classes, Jorge Mpodozis has certainly drawn attention to the great importance of not confusing mechanisms with the result of the operation of these mechanisms, because the consequence of this operation is something that is in the future, it has not yet happened; and as such, it cannot serve as a guide for what is going on in the present. And that is what we inadvertently do when we think of immune “defense” as a mechanism.

A third option: neither “strangeness” nor chance

If we really lived by chance, as the most accepted evolutionary and immunological theories propose today, it would be impossible to find regularities, constants in immunological activity; conserved elements, which appear again in a predictable way whenever the conditions that gave rise to them are repeated. The search for this conservation evidence in immunological activity constitutes a third option, which avoids being based on the idea of “strangeness” and also avoids invoking the notion of chance events. This option puts lymphocyte interactions between themselves and lymphocytes with the organism at the center of attention. If we are going to see the immune system as a system, which is part of this larger thing which is the organism, the medium in which the immune system operates is the organism of which it is a component. The medium in which the organism operates is a meta-medium that remains inaccessible to the immune system. On the other hand, the immune system is always in contact with the organism, even when it is penetrated by materials that do not belong to it, such as food molecules. It is not for the immune system, however, to decide whether the origin of the materials it contacts is inside or outside the body; if they were always there, or if they came up now.

We will therefore insist on evidence that the immune system forms a cohesive network of interactions, dynamically stable, which has conserved elements and invariant characteristics, but which, on the other hand, is incapable of intelligent actions. The intelligence or intentionality that we attribute to the immune system, in reality, is in those who perceive these qualities: it is in immunologists, in immunological observations. Immunological activity is not simply mechanical because it has a history, in which we are going to introduce these systemic elements to describe what happens; it is also not supernatural because it is human beings who describe it.

So, specific immune responses, immune tolerance, everything that derives from this stimulus / response / regulation model will be replaced by a robust stability network, which goes through disturbances and compensates them. Disturbances are not stimuli and compensations are not responses, because we talk about something (a system) that is disturbed, and we see this system as capable of compensatory actions, whereas, in the previous view (stimulus-response), we can limit ourselves to study the agents stimulants and the components that arise in response to them (antigens and antibodies). The notion of “regulation” can also be a false shortcut, as it can be seen as “regulatory responses”; this would lead us to an endless number of answers, without a theoretical model capable of accommodating them. After all, who regulates the regulator? On the contrary, the analysis of disturbances and compensations refers to the study of systems determined in their structure, something similar to the fish that Mpodozis explained in his class (Figure 2, p. 37).

A radical way of perceiving the differences between these two ways of seeing is to distinguish between two terms that are usually seen as synonyms: immunoglobulins and specific antibodies. Immunoglobulins are components of the immune system that appear spontaneously in the body’s dynamics, while specific antibodies are functional entities that arise with a purpose (a specificity) in serological tests designed exactly to characterize these entities. When we “type” red blood cells with an “anti-A serum”, we usually imagine that this serum contains molecules specifically capable of reacting with A-positive human red blood cells; and this is correct. But the immunoglobulins that are there react with bee honey, okra drool and Shigella flexneri – in short, with a number of things that have carbohydrates similar to those present in A-positive red blood cells. They were not made to react with human A-positive red blood cells, they did not arise as a result of previous contact with these red blood cells. In the organism where they were collected, these immunoglobulins – which are hundreds, thousands of different molecules – reacted with other molecules, including other immunoglobulins. But the test, the typing, works effectively: the test is specific, because it uses immunoglobulins as if they were specific biochemical reagents; and in the test, they work just like that. They are, of course, not specific biochemical reagents, but creations of the organism, as part of the network that makes up the immune system. The study of antibodies is a perfectly legitimate activity; however the study of natural immunoglobulins is something else, little explored so far. Jerne went on to say that “the difference between natural globulins and specific antibodies exists only in the minds of immunologists” (SÖDERQVIST, 2003, p. 185).

Paying attention to what happens in human “language”⁷ is another important aspect of this systemic view. Unfortunately, we will not have time to deal with human language in more detail here, but I still feel it necessary to make some comments on this. Human language is also usually seen as the transmission of symbolic information; but, in the Biology of Cognition and Language, living in language (languaging) becomes a typical human way of living – living recursively in coordinating coordinations of consensual conducts. Language in Maturana is also not treated in terms of an information biology. This is not an easy subject to address. At the last SBPC meeting, held at UFSC, I participated in a round table whose theme was “The origin of the human”, and I tried to convince my colleagues that we would have to pay attention to what happened when we talked, because it was the conversation that made us humans; that humans emerged when conversation, living in language, developed. However, I was not very successful. It is very difficult to accept that speaking and listening, or rather, coordinating consensual actions and coordinating coordinations of actions, constitute a way of life and that is what made us and keeps us being human, as a particular type of animal, a particular type of primate . The primacy of “doing”, of actions, is made explicit in the title of a recent book by Maturana, the result of a long interview with a German journalist, called From being to doing (MATURANA; POERKSEN, 2005).

Finally, I just want to mention the concept of Natural Drift, which Jorge Mpodozis is exploring in his classes. Usually, we think that a boat drifting in the ocean will go anywhere, but it only follows a single route, which is determined by its size and weight, the wind, waves, currents and tides. Eventually, this drift ends when the boat collides with a rock or hits a beach. But that end point never worked as a reference for the movement of the boat, so we cannot say that it “approached” the rock or the beach. Its movement, its drift, were created instant by instant, and the present did not contain the future. This mistake, of explaining the future by the present, of confusing mechanisms with the result of its operation is at the core of current biological and immunological thinking, because it is part of the idea of “adaptation”, of the conception that living beings change “to” become something else in the future, and that each structure has a function.

In short, I want to treat the immune system as a real system, a lymphocyte network, in which intervening on a lymphocyte affects the others, and eventually all the others; that the medium where the immune system operates is the organism of which it is a component. The “strangeness”, the ability to discriminate, separate, distinguish between own and foreign materials is a pseudo-problem, because the immune system never does this, since it is always in contact with the organism and, as such, never finds components of the environment in which the organism lives, which is a meta-medium to the immune system. The intelligence of the immune body is in our observations and not in the elements that make up the system.

Attention focused on stimuli and responses has already dominated psychology. Behaviorism, a dominant way of thinking in Psychology in the 1950s, was labeled by its opponents Stimulus-Response (SR) Psychology, because, in this way of seeing, the organism is reduced to the “hyphen” that links S to R. In its immunochemical period (1910-1960), Immunology was behaviorist, that is, it concentrated on studying antigens and antibodies. What is left out in this view is the study of the organism, the changes that constitute it, its physiology; or rather, a distinction is missing between two domains that do not intersect: between what happens in the organism and what happens with the organism. Living beings are systems in continuous change, they are not ready, and they only remain when they die; then, they stop the changes that characterized living – and start others. This will be addressed in the course of our conversations, because, in the way that we prefer, individual health is a collective problem. It depends on the situations we live in, that is, this way of seeing also changes the concept of health.

And we need to redouble our attention with the notions that we will call systemic. On the one hand, the concern about systemic and cognitive problems has increased a lot. MIT itself recently launched a quarterly publication entitled Biological theory, which includes the term Cognition in its subtitle, that is, not only does it speak more about dynamic systems, but it also feels the need to talk about the observer, about what is known. In fact, I suggested to Jorge Mpodozis that, in the reconstruction of his Experimental Epistemology laboratory, recently destroyed by fire, he should adopt a new name: Epistemological Observatory. We are all observers, and observation is seen as a key element in our knowledge. So, why call it a laboratory and not an observatory? Why reserve this for astronomers if we all work at observatories and are observers.

To say that the organism is the medium where the immune system operates has serious implications. It seems very difficult to apply this idea to other systems that operate within the body, such as the nervous system. But that is exactly what Maturana and Mpodozis propose. Mpodozis is one of the rare neurobiologists on the planet who treats the nervous system as a closed neuronal network on itself and does not use the concept of information – as he himself demanded the right to a non-informative biology here. The nervous system, as well as the immune system, can also be seen as a closed (neuronal) cellular network, which undergoes disturbances in its contact with the organism and changes its structure in compensation for these disturbances. The other day, we talked about proprioception, about our ability to feel where the parts of our body are – where my left foot is – or to gather the tips of my index fingers in front of me while keeping my eyes closed. Professor Fernando Pimentel, who taught neurobiology at the ICB at UFMG, had several aquariums with small electric fish from the Amazon, with which he made impressive demonstrations of the proprioception of these little animals – which, in the case of this type of fish and platypuses, acquire external dimensions to the body. The electric fish moves more or less in the center of an electromagnetic sphere that it generates, and it uses deformations in that sphere to orient itself in the cloudy water seeing nothing – they are practically blind – and also to hunt. Its electric field detects its prey like other electric fields, which deform its own field. The demonstrations that this teacher made consisted of asking students to take sticks with a ring at the end and try to get the fish to pass through the ring. This was perfectly possible if the ring were plastic, but impossible if metallic; the animal always dodged. Perhaps we could use this example to feel that we are within spaces, dimensions, that we ourselves generate and whose disturbances we make compensations for. And that doesn’t just apply to the immunological dimension.

References

• BILLINGHAM, R. E.; BRENT, L.; MEDAWAR, P. B. Activity acquired tolerance of foreign cells. Nature, n. 172, p. 603-606, 1953.
• BURNET, F. M. A modification of Jerne’s theory of antibody production using the concept of clonal selection. Australian Journal of Science, n. 20, p. 67-69, 1957.
• BURNET, F. M. The Clonal selection theory of acquired immunity. Cambridge: Cambridge University Press, 1959.
• CANNON, W. B. The wisdom of the body. New York: W. W. Norton, 1932.
• CLAYTON, J. Lymphocytes: not useless after all. Journal of Experimental Medicine, n. 203, p. 487, 2003.
• JERNE, N. K. The natural Selection theory of antibody formation. Proceedings of the National Academy of Science USA, n. 41, p. 849-857, 1955.
• LACROIX-DESMAZES, S. et al. Stability of natural self-reactive antibody repertoires during aging, Journal of Clinical Immunology, n. 19, p. 26-34, 1999.
• LANZAVECCHIA, A. Antigen-specific interaction between T and B cells. Nature, n. 314, p. 537-539, 1985.
• LETTVIN, J. Y. et al. What the frog’s eye tells the frog’s brain (1959). In: McCulloch, W. S. (Ed.). Embodiments of Mind. Cambridge: MIT Press, 1975. p. 230-256.
• MILLER, J. F. A. P. Immunological role of the thymus. Lancet, 2, p. 748-749, 1961.
• MITCHISON, N. A. Passive transfer of transplantation immunity. Proceedings of Royal Society of London B, n. 142, p. 72-75, 1954.
• MATURANA, H. R.; URIBE, G.; FRENKE, S. A biological theory of relativistic color coding in the primate retina. Archivos de Biologia y Medicina Experimental, n. 1, p. 1-30, 1968.
• MATURANA, H. R.; VARELA, F. J. The Tree of Knowledge. Biological Basis of Human Understanding, Boston: New Science Library, 1987.
• MATURANA, H.; POERKSEN, B. From Being to Doing: The origins of Biology of Cognition. Heidelberg: Carl-Auer, 2004.
• SÖDERQVIST, T. The life and work of Niels K. Jerne as a source of ethical reflection. Scandinavian Journal of Immunology, n. 55, p. 539-545, 2002.
• SÖDERQVIST, T. Science as autobiography: the troubled life of Niels Jerne. New Haven: Yale University Press, 2003.
• TAUBER, A. I. The immune self, theory or metaphor? Cambridge: Cambridge University Press, 1994.
• VAZ, N. M.; VARELA, F. J. Self and Nonsense: an organism centered approach to immunology. Medical Hypothesis, n. 4, p. 231-267, 1978.

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Chapter 2.4 – History in lymphocytes – A conservative physiology for the immune system 

Nelson Monteiro Vaz

This work that I intend to expose in the next lines depended on the collaboration of several people. Gustavo Ramos, who is my collaborator in several texts; Vitor Pordeus, also co-author of several activities with us, currently involved in a work of reconciliation between art and science; Cláudia Carvalho, who is my wife, professor at the Morphology Department at UFMG and a collaborator for many years; and Archimedes Júnior, who is a doctoral student.

At the outset, I would like to express my satisfaction with the opportunity to make some comments in an environment of rich general biological reflections, such as those developed by Professor Mpodozis. Now, I am going to refer to a much thinner fillet in the biological world, but one that acquires great importance because Immunology is the area of biomedicine from which society most demands results. If a television station does a general report at a university, I am sure that the Immunology labs will be visited and questions about vaccines will be asked. Society, however, has a false, altered view of what it may require from Immunology and asks it for a safe method of transplanting tissues, an AIDS vaccine, curing allergies – a number of things that are not available today .

Very influenced by the ideas of Mpodozis and Maturana, I started to understand Immunology in an unusual way and, just as Mpodozis puts arguments, in my view, very strong and incompatible with the dominant view in Biology, the genocentric conception, what I think, is also contrary to the dominant view in immunology. And the clearest way I have to put this view is to speak of a conservative physiology for the immune system, because it is curious that, unlike other manifestations of biological activity, Immunology does not have a physiology. Immunologists do not talk about what happens to the immune system when everything is going well, as long as we remain normal; and physiologists, usually, do not live the problems experienced at the borders of Immunology. I want to put this story of the normal operation of the immune system out of crisis situations.

The idea of recognizing materials foreign to the body reveals two things. First, that Immunology is full of cognitive metaphors; for recognizing, discriminating, separating and maintaining the memory of something are certainly cognitive activities. Second, in the usual view, the target of this “recognition” is misunderstood, because the mass of “foreign” materials with which the body comes into contact daily comes from our diet, from what we eat as food and from the intestinal microbiota, not of dangerous microbes. The presence of lettuce proteins, for example, in our circulation, is something very strange. We learned at school that all the proteins we swallow are digested with amino acids, but that is not true. If we eat an egg and then collect some venous blood, we will see that, in five minutes, all the proteins in the egg will be detectable in the circulation by immunological methods. In a pregnant rat, these proteins pass into the fetal circulation also in minutes. Anyway, we are not impervious to the penetration of quantities of proteins perfectly capable of triggering immunological phenomena, which are in the range of nanograms or micrograms per milliliter. So, if I go to the Northeast and like all the fish, crustaceans and mollusks that are offered to me, a zoo of foreign proteins enters my circulation. And what happens to me? Fattening.

This normality of immunological activity is beyond the attention of immunologists. The native microbiota that we carry in the digestive tract is another great source of materials to which we are continuously exposed. Recently, it has been shown that the intestinal flora of obese people is different from that of non-obese people and that a weight loss regime modifies the intestinal microbiota (LEY et al., 2006). There are seven hundred different species of bacteria already characterized in the human oral mucosa (CURTIS, 2003). In the intestinal microbiota, this diversity is hundreds of times greater. And we still misunderstand the daily relationships of these microorganisms with the body.

It is not that I am a pessimist, but I tell students that Immunology is not a good area to start a research career, because, in a way, it is agonized, linked to metaphors created 150 years ago and that now cannot stand the weight of paradoxes in immunological discourse. On the one hand, there is tremendous methodological sophistication; and, on the other hand, a great difficulty in translating this knowledge into clinical advances. If we consider the invention of vaccines and other forms of therapeutic intervention as measures of the effectiveness of this discipline, Immunology would be a failure, for failing to fulfill the task for which it was created: it did not invent the vaccines that it was expected to invent. We think that it was Immunology that created the vaccines, but they were the ones that created Immunology. When the first vaccines were invented, a whole area of medical bacteriology was dedicated to inventing new vaccines. And although this topic is not publicly known, in the vast majority of cases, it did not work.

This is illustrated in Figure 14, which shows the years when vaccines were introduced into medical practice and, at the same time, the number of pages in the Journal of Immunology, as a measure of the growth of knowledge in Immunology. It is clear that this knowledge has not been translated into practical applications, because the number of invented vaccines has not grown as expected.

In my view, the area to begin biological research should be the general one to which Mpodozis refers and which asks about the directions that follow the development. This is the great open horizon with all the methodology of molecular genetics and cell biology. The implementation of this way of seeing in Immunology must have a theoretical parallel; it also needs to generate tools for argumentation and a research problem similar to the one he offered us here in the previous lecture. What I am going to say may be very little ahead of what he suggests, but perhaps it will help to simplify some aspects of immunological research. Let’s see.

Figure 14  The years when vaccines were introduced into medical practice and, at the same time, the number of pages in the Journal of Immunology

A way of seeing

I will essentially make considerations about a way of seeing. If we are going to describe a conservative physiology of the immune system, we need to pay close attention to the meaning of these words, that is, what is conserved in the activity of the immune system; what we call physiological activity and what we define as a system. The term “immune system” is trivial and commonplace in immunology and is mentioned by all immunologists; but the object of study of this discipline, in reality, is a collection of lymphocyte clones dissociated from each other, which in no way constitutes a system. In the simplest description, a “system” is a set of elements connected to each other in such a way that, if we move with one of these elements, it will affect the others. This is not clear in the mainstream of immunology; it would appear that lymphocytes are independent of each other (“specific”) and also independent of the organism they inhabit, of which they are a part (devoid of “autoreactivity”). In my view, the theoretical situation of Immunology is, in short, very precarious.

Conservation and physiology are words linked to normal living, healthy living. Therefore, we have to approach a problem in health, in what happens while we are not sick. I will deal with the immunoglobulins that we call “natural”, which are present in animals that have not been or are ill, nor have they been artificially immunized, that is, they have not passed through the hands of immunologists. These immunoglobulins have very interesting properties. A systemic approach to immunology requires a clear and rigorous definition of terms such as structure and organization. The structure of living beings, in general, and that of the immune system, in particular, is continuously changeable, involves incessant cellular and molecular exchanges, but there are aspects of this substitution that are conserved. There are relationships between cells and between molecules that remain invariant, and this conserved portion is what will allow us to define how the immune organization system is constituted.

The traditional view admits that there is an unlimited variety of antigens to which the body can respond in a particular way (specific, fit) for each of them; the apparent reconciliation of these two antagonistic properties (unlimited versatility and particularity) was what attracted some notable thinkers from the 19^th and 20^th centuries to Immunology. What I am going to say replaces this traditional idea that we are moved by chance encounters, at random, with strange materials, by the concept of an invariant organization in the immune system. In addition, I will defend the argument that the immune system also experiences a drift, just like a drifting boat, as part of the Natural Ontogenetics and Phylogenetics Drift proposed by Maturana and Mpodozis (2000). The living systems and the subsystems that make up a living being live in a continuously changing present, like a boat adrift, that is, without a future point, acting as a reference in its historical development. Finally, we are going to oppose the idea of chance, of random variation, to the concept of a natural drift of the immune system. Because a drift is created moment by moment, contingent on several parameters, but in a way perfectly determined by the history of encounters that a system determined by its structure establishes with the environment in which it operates.

The examples of conservation of immune activity, which I want to put as physiology, are very varied, but I will choose two examples with which I am experimentally familiar. One has to do with contact with the antigenic materials in the diet, which happen to all animals all the time, which is happening to us now – breakfast is still being processed. And another aspect that has to do with natural immunoglobulins, which are produced “spontaneously”.

Oral tolerance

“Oral tolerance”, as it is usually defined in the Immunology of our relationship with what we eat, is not exactly what immunologists call “tolerance”, that is, a delayed denial. It is not an inhibition, or erasure of specific immune reactivity; it is not even oral, as it can be achieved through the nasal route; it does not occur in neonates, it does not take place in an immature organism, such as tolerance to skin transplants from another animal. The notion of “immunological tolerance” is very attached to the pioneer experiments that characterized the tolerance to allogeneic skin transplants (from another organism of the same species), because these experiments, carried out in England in 1953 (BRENT, 1997), ended up giving rise to Clonal Selection Theory in Australia in 1957, and this is still the dominant theory in Immunology.

The induction of tolerance to allogeneic skin grafts (from another lineage, genetically distinct) requires neonatal mice, with up to 24 hours of birth; the susceptibility to tolerance induction is evanescent, as it disappears completely at three days of age. In contrast, food tolerance (“oral tolerance”) requires young animals already competent for immunological activity. It is not a subtraction, as it was believed to be allograft tolerance, because when lymphocytes are transferred (adoptively) from oral tolerant animals, they take this tolerance with normal animals. Tolerance is, therefore, more of an addition, an addition, than a subtraction in reactivity. There is a very good review of the history of “oral tolerance” in the literature (BRANDTZAEG, 1999), as well as short (VAZ et al., 1996) and long (FARIA; WEINER, 2006) reviews of its phenomenology.

This phenomenology is revealed in a very simple way: if an animal ingested or received through a gastric tube (by gavage) an antigen that it had not contacted before, it will respond with less intensity to the subsequent immunization (subcutaneous, intraperitoneal, etc.) with the same antigen (in adjuvants), as control animals that did not ingest the antigen. Under maximum conditions, this intake virtually abolishes all manifestations of specific reactivity to the antigen in vivo and in vitro, that is, the tolerant animal forms much less antibodies or reacts with much less inflammation to injections of the antigen; their T lymphocytes expand much less intensely if exposed to the antigen in vitro (Figure 15).

Figure 15  “Oral tolerance”

This is a dramatic transformation in reactivity, which sets in quickly (less than 24 hours) after exposure to relatively small doses of protein. A single 20 mg dose of ovoalbumin (Ova), which represents less than one percent of an adult mouse’s daily protein intake, is able to significantly reduce the animal’s anti-Ova responses for the rest of its life (FARIA et al., 1998).

This means very little from a nutritional point of view, it means a lot from an immunological point of view. The ingestion of 20 mg of Ova puts a total of 2-10µg of Ova in the circulation in the minutes after ingestion; but the injection directly into the vein of 20 µg of Ova, although it reduces the subsequent specific reactivity to about one third, is much less efficient than ingesting the antigen to induce tolerance (Table 2).

Table 2 – Effect of previous intravenous injection or ingestion of ovo albumin (Ova) on the secondary immune response subsequent to Ova + adjuvant (ip).

Day – 7	Day 0	Day 35
nothing	0 ± 0	469 ± 123 a
20 µg Ova (iv)	7 ± 1	151 ± 48
20 mg Ova (gavage)	0 ± 0	1 ± 1

B6D2F1 mice of 8 weeks immunized (ip) on days 0 and 21 with 1 µg Ova + 1 mg Al (OH) 3; µg Ova bound / ml serum (ABC-33)

This is probably because the large mass of lymphocytes involved in these phenomena is in the mucosa of the duodenum and the proximal jejunum; eight out of ten immunoglobulin-secreting cells in the body are in the small intestine, a very important organ in immunological activity.

We investigated whether oral tolerance occurs with the proteins present in the feed of the vivarium, which animals normally eat, and the answer is yes. Laboratory mice are tolerant, for example, to zein, a protein component of corn contained in food rations, and also to antigens in their intestinal microbiota. It is amazing and, at the same time, understandable that this is not explained with emphasis in the textbooks of Immunology, because this phenomenon goes against everything that is taught in terms of “defense” against materials foreign to the body. Oral tolerance raises a series of problems, which immunologists do not seem very willing to face, or put in a special “drawer” and deal within a way dissociated from the general problems of immunological activity.

As they age, mice lose their susceptibility to oral tolerance. Exposing senile mice, one and a half years old, to 20 mg of Ova no longer makes them tolerant. Interestingly, if these senile animals receive spleen cells from young adults, they regain their susceptibility to tolerance and, conversely, young adults become less susceptible if they receive cells from senile animals (LAHMANN et al., 1992).

Stability levels

There is a phenomenon that I would like to be particularly clear about: it concerns what goes on in mice that become “partially” tolerant. In fact, this happens in all experimental situations, that is, animals that ingest the antigen never completely lose their specific reactivity, although it is reduced in the inverse ratio of the ingested antigen dose, to induce tolerance; if this dose is large, the animal seems to lose all reactivity; but, if it is smaller, residual reactivity remains. What is remarkable about this residual activity is that the level of antibodies still formed, in response to a secondary injection of the antigen, stabilizes at a level that cannot be broken by several subsequent injections of the same antigen (Figure 16). In other words, depending on the ingested dose of antigen, the animal establishes levels of reactivity that, from then on, remain stable (VERDOLIN et al., 2001).

This simple-looking phenomenon can totally change the way we view oral tolerance and also several other immunological phenomena – what we think about allergy, autoimmune diseases and immunology in general, that is, the process, not just the event, which takes place in these animals, is something that deserves to be analyzed. This process that takes place in partially tolerant animals is not an inhibition of the response, but a dynamic stabilization of levels of reactivity. Oral tolerance acquired this label of inhibitory phenomenon because, when this level is established at very low values, it really appears as an inhibition. But this is an extreme situation; there are intermediate levels, in which the animal could not be properly called “tolerant”, as it is forming very significant rates of specific antibodies, nor does it show a “secondary” type of reactivity to the antigen. Therefore, it has no “memory” of previous contacts with this antigen, that is, it does not exhibit progressive reactivity to antigens. This animal is neither “immunized” nor “tolerant”.

We need other terms, other concepts to talk about this phenomenon. Dynamic stability is established here, rather than progressive reactivity, which is what is traditionally imagined to happen with immune reactivity. A progressive reactivity is what is imagined to happen in the protection afforded by anti-infectious vaccines and, due to the enormous importance of the vaccination concept, this idea is spread throughout Immunology.

Figure 16  Stability levels for the production of immunoglobulins reactive to the tolerated antigen

Something similar is happening with allergic sensitivity and autoimmune diseases. Non-allergic individuals, who have no clinical sensitivity to environmental allergens, form small amounts of sensitizing antibodies (IgE) to the most common allergens. The main difference between these individuals and allergy sufferers is that this subclinical sensitivity is kept stable. It does not increase in successive encounters with allergens, while allergy sensitivity is unstable and progressive, exacerbated with each new encounter with allergens. The same reasoning applies to autoimmune diseases. If we look for antibodies against human retinal antigens in normal individuals, we will be surprised to find that they exist. Likewise, if we look for activated T lymphocytes reactive with the human pancreas, they will be there. But in the normal individual, unlike the person with retinal lesions, or the type-I diabetic, these antibodies and lymphocytes are not progressively increasing their reactivity in successive pathogenic episodes; they are stable.

What happens in allergic and autoimmune diseases is a breach of that stability that characterizes us as normal individuals. The organism exhibits a stable autoreactivity and also reacts stably to allergens with which it comes in contact.

An immune tone

There is another aspect of this dynamic stability of the immune system that we have also investigated in our group. If our claim that contacts with dietary proteins are really important in immunological physiology, a diet without proteins, but nutritionally balanced with amino acids, should have serious consequences on immunological activity. We have tested this in our laboratory in recent years and, indeed, mice kept since weaning on a diet like this, even in open cages, containing a supposedly normal microbiota, are immunologically abnormal from a functional and morphological point of view. As expected, there is a large reduction in the lymphoid tissue associated with the intestine, but the pulmonary lymphoid tissue is also reduced. There are changes in the peripheral lymph nodes and in the thymus itself, and a great reduction in the concentrations of IgG and IgA, but not of IgM, in the circulation – this is important, as we will see later. Animals grow normally, look normal. However, the histology of a lymph node is similar to that of mice with severe immunodeficiency syndromes (MENEZES et al., 2003). Our data show that animals deprived of a protein diet showed a great reduction in the volume of Peyer’s patches and, also, in the number of intraepithelial lymphocytes.

This suggests that there is an immune tone to which contact with dietary proteins contributes significantly. Therefore, the protein diet is important not only from a nutritional point of view, but also for our immune health, especially in childhood. This is possibly also important for patients who, for various medical reasons, are fed intravenously for prolonged periods.

Systemic effects of parenteral contact with the tolerated antigen

Another important aspect in this area has been investigated by Cláudia Carvalho and consists of understanding what happens in the injection of tolerated antigens in tolerant animals. Why investigate this? Because we know that “oral tolerance” can be transferred “adoptively” from one animal to another with lymphocytes. Therefore, something comprehensive happens in the tolerant organism when these lymphocytes come into contact with the antigen. We found that when an “oral tolerant” animal by previous ingestion of a protein (for example, Ova) is injected with that same protein in a mixture with another (for example, hemocyanin), initial (primary) responses to that second unrelated protein are also strongly inhibited (CARVALHO et al., 2002). Thus, a single injection of small doses (10 µg) of ovoalbumin (Ova), applied to animals that previously ingested this protein and became “oral tolerant” to it, is able to dramatically inhibit other immune / inflammatory processes, such as formation of granulomas around Schistosoma mansoni eggs injected intravenously into uninfected animals (CARVALHO et al., 2002). This is a beautiful demonstration of lymphocyte interconnectivity, still unexplored as a therapeutic resource (Figure 17).

This systemic character of the phenomenon of oral tolerance is sufficient to prevent the death of B6D2F1 mice injected as lymphocytes of the parental lineage (C57BL / 6) that provoke a reaction known as GvH (Graft versus Host) or “transplant-against-host”, which is the main complication of human bone marrow transplants, responsible for the death of a significant percentage of transplant patients. We show that when Ova-tolerant B6D2F1 animals are injected with a small dose (10 µg) of Ova along with lethal transfusion of parental cells, they survive for a much longer time, or do not even die; the same does not occur with B6D2F1 animals not made tolerant to Ova.

Figure 17  Indirect effects of oral tolerance on pulmonary granuloma formation

Natural immunoglobulins

When I was a boy, my father took me to Cineac Trianon, on Avenida Rio Branco, in Rio de Janeiro, a cinema dedicated to cartoons and small documentaries, whose motto was hospitable: “The show starts when you arrive”. Indeed, as the films presented were all relatively short, something always started as if it was tailored to our arrival. We stayed there for a little over an hour, when then what we had seen was repeated and we knew it was time to go. But the idea that our arrival governed the show was illusory.

Something similar is happening with immunological activity. The first tendency to explain it is to think that antigens induce immune responses, or rather, that antibodies are tailor-made for them (they are “specific”), arise in response to their stimulus. Some even think of a two-way correspondence, that is, a specific antibody for each antigen. But this is an illusion: there are many demonstrations that the production of immunoglobulins takes place in a totally different way. And my second argument, in defense of a conservative physiology of the immune system, has to do with natural immunoglobulins, that is, those formed spontaneously, without human intervention. In other words, without antigenic stimuli.

The method I will describe was developed by Alberto Nóbrega (currently at UFRJ), Mathias Haury and Alf Grandien, at the Pasteur Institute, in Paris, in the 1990s, and consists of a modified form of immunoblot to analyze the reaction of the IgM or IgG present in blood serum, with complex mixtures of proteins – organ extracts (brain, muscle, etc.) or whole bacterial cultures – previously separated by polyacrylamide electrophoresis (NÓBREGA et al., 1993; HAURY et al., 1994).

As could be expected, the reaction of the serum with such mixtures produces a large number of reactions, which manifest themselves as a forest of peaks of reactivity, when measured by densitometry. Transferred to a computer, this data is analyzed by software specially developed for this. This is a way of looking at the overall reactivity profile of immunoglobulins, rather than quantifying the production of a specific antibody. It was observed that these reactivity profiles are established early in ontogenesis and, particularly, the IgM reactivity profile has three important characteristics: (a) it is of an impressive robustness, that is, it remains invariant throughout the healthy living (LACROIX- DESMAZES et al., 1999); (b) does not seem to be influenced by contact with proteins from the intestinal flora or from the diet, as it remains invariable in antigen-free animals (HAURY et al., 1996); and (c) it is influenced by important genes in immunological activity, such as those of MHC, that is, it is not established at random (VASCONCELLOS et al., 1998). The reactivity profiles of IgG with organ extracts are also very stable, although those of reactivity with bacteria vary slightly with aging (LACROIX-DESMAZES et al., 1999).

The stability of these reactivity profiles, especially IgM, is another phenomenon that goes against the expectations generated by Immunology, which suggest constant changes in reactivity in a continuously changing immune system. A normal mouse replaces virtually all of its lymphocytes with others in a few weeks. How can these patterns remain stable? The idea that the reactivity of the immune system is created by encounters with environmental antigens and that natural immunoglobulins result from low-intensity immune responses to these antigens is therefore false; such reactivity profiles do not change in animals deprived of contact with germs and antigens in the diet (germfree and antigen-free). We form our immunoglobulins, IgM certainly, and a good part of IgG, in the same way that we build our organs and tissues; this is a process internal to the organism, modified, of course, by interactions with the environment, but which has an origin essentially internal to the body.

Very recently, McCoy and collaborators (2006) studied the IgE present in normal, non-allergic organisms, not infected with helminths. Surprisingly, this “natural IgE”, which exists in low amounts in all of us, differs significantly from the IgE usually studied experimentally, specific for allergens and worms. The “natural IgE” rises in germfree animals, and also in all states of immunodeficiency T (in nude mice, for example), in the germinal centers in the lymphoid follicles where somatic mutations occur that are not necessary for the synthesis of “natural IgE “; CD25 + Treg cells that are important in inhibiting experimentally induced IgE do not affect “natural IgE”; allergic states are more frequent in young organisms, while this “natural IgE” rises in elderly organisms (MCCOY et al., 2006). Anyway, we still know very little about the biological significance of IgE.

Researchers studying IgA are coming to similar conclusions. Ask any immunologist what IgA is for and he or she will tell you that it is for mucosal protection. Well, it is true that virtually all intestinal bacteria are found to be coated with IgA. When a germfree animal, which forms very little IgA, is colonized with one or two species of intestinal bacteria, there is a real explosion in the synthesis of IgA, but only about 1-2% of this IgA reacts with the bacteria used (BOS et al., 1999). Therefore, we don’t understand IgA either.

IgG patterns characteristic in diseases

Parisian research groups, such as those by Coutinho and Kazatchkine, had shown that, in several human autoimmune diseases, as well as in experimental models of autoimmunity in animals, characteristic variations in the IgG reactivity profile emerged (SUNBLAD et al., 1997). It is important to note, again, that this reactivity was tested against organ or bacterial extracts, which in no way resemble antigens supposedly involved in autoimmune diseases. This would suggest, therefore, that during autoimmune diseases, such as lupus erythematosus, myasthenia gravis, etc., there are standardized and predictable variations that appear in “different clinical states” – an observation of enormous importance for understanding the dynamics of these pathological states.

In our laboratory, we tested human and mouse sera with parasites in which “autoimmune” factors have been claimed to play an important role in determining “clinical conditions”, with varying degrees of severity. Indeed, we proved that, in human malaria, in human and mouse schistosomiasis mansoni and in mouse leishmaniasis, it is possible to characterize the “clinical states” – that is, the different forms of the disease’s manifestation – through IgG immunoblots against E. coli or organ extracts. This reinforces the previous statement that it is possible to characterize the various pathological states through analysis of changes in the profiles of circulating IgG (FESEL et al., 2005).

This is a frontier that opens, unexpectedly, in Immunology, which is not based on traditional “serological” analysis, that is, it does not seek to detect and measure specific antibodies. What happens in the immune system, in the disease, are not random variations, nor are they just variations directly related to antigens of an infectious agent, or of the autologous organ affected in autoimmune diseases; they are characteristic variations linked to genetic and epigenetic characteristics of the organism.

The significance of these phenomena is still unclear, but I believe that we are better off than we were with the characterization of specific antibodies. So, in the traditional view, based on specific immune reactivity, what can we say about pathogenic changes? Either reactivity is insufficient, and we speak of immunodeficiencies, or it is excessive, and we speak of allergies when there is an unnecessary hyperreactivity to innocuous antigens; or pathogenic autoimmunity, when this reactivity deviates and affects internal organs and tissues. We can think about solving immunodeficiencies with several ways to reinforce immune responses and to resolve allergies and autoimmune diseases by inventing methods to induce immune tolerance.

But all of this goes beyond understanding the physiology of immune activity. We ignore what happens during healthy living and therefore have difficulties in understanding the pathological deviations of these mechanisms. And what triggers immunological pathology? We need to imagine mechanisms immanent to the system’s own operation, that allow us to see the pathology arise from deviations from a normal physiological activity. If physiology constitutes an adequate plurality among the components of the immune system, an adequate interconnectivity, the pathology must spring up when that connectivity becomes inadequate and this abnormality acquires progressive characteristics. Most likely, a wide avenue of entry into this problem will open with the study of the diversity of lymphocyte populations involved in these events. But on this subject, I hope to delve deeper into an upcoming essay. What I would like to do on this occasion is to return history, or rather, a physiology to Immunology, because that seems central to me; however, it is virtually absent from the immunologists’ view. And, in this sense, I believe that identifying stable patterns and natural immunoglobulins inaugurates another way of seeing, which is no longer focused on specific and individualized antibodies, but rather on a systemic / historical approach to Immunology.

References

• BOS, N. A.; JIANG, H. Q.; CEBRA, J. J. T. cell control of the gut IgA response against commensal bacteria. Gut, n. 48, p. 762-764, 2001.
• BRANDTZAEG, P. History of oral tolerance and mucosal immunology. Annals of the New York Academy of Science, n. 778, p. 1-26, 1996.
• BRENT, L. The discovery of immunological tolerance. Human Immunology, n. 52, p. 75-81, 1997.
• CARVALHO, C. R. et al. Indirect effects of oral tolerance to ovalbumin interferes with the immune responses triggered by Schistosoma mansoni Brazilian Journal of Biological and Medical Research, n. 35, p. 1195-1199, 2002.
• COUTINHO, A.; KAZATCHKINE, M. D.; AVRAMEAS, S. Natural autoantibodies. Current Opinion Immunology, n. 7, p. 812-818, 1995.
• CURTIS, M. A. Summary: microbiological perspective. Molecular Immunology, n. 40, p. 477-479, 2003.
• FARIA, A. M. et al. Aging affects oral tolerance induction but not its maintenance in mice. Mechanisms of Ageing Development, n. 102, p. 67-80, 1998.
• FARIA, A. M.; WEINER, H. L. Oral tolerance: therapeutic implications for autoimmune diseases. Clinical and Developmental Immunology, n. 13, p. 143- 157, 2006.
• FESEL, C. et al. Increased polyclonal immunoglobulin reactivity toward human and bacterial proteins is associated with clinical protection in human Plasmodium infection. Malaria Journal, n. 4, p. 5-11, 2005.
• HAURY, M. et al. Global analysis of antibody repertoires. 1. An immunoblot method for the quantitative screening of a large number of reactivities. Scandinavian Journal of Immunology, n. 39, p. 79-87, 1994.
• LACROIX-DESMAZES, S. et al. Stability of natural self-reactive antibody repertoires during aging. Journal of Clinical Immunology, n. 19, p. 26-34, 1999.
• LAHMANN, W. M et al. Influence of age on the induction of oral tolerance in mice and its adoptive transfer by spleen cells. Brazilian Journal Biological and Medical Research, n. 25, p. 813-821, 1992.
• LEY, R. E. et al. Microbial ecology: human gut microbes associated with obesity. Nature, n. 444, p. 1022-1023, 2006.
• MATURANA, H. R.; MPODOZIS, J. The origin of species by means of natural drift, Revista Chilena de Historia Natural, n. 73, p. 261-310, 2000.
• MCCOY, K. D. et al. Natural IgE production in the absence of MHC Class II cognate help. Immunity, n. 24, p. 329-339, 2006.
• MENEZES, J. S. et al. Stimulation by food proteins plays critical role in the maturation of the immune system. International Immunology, n. 15, p. 447- 455, 2003.
• NÓBREGA, A. et al. Global analysis of antibody repertoires. II. Evidence for specificity, self-selection and the immunological “homunculus” of antibodies in normal serum. European Journal of Immunology, n. 23, p. 2851-2859, 1993.
• SILVA NETO, A. F. Desenvolvimento ontogenético do repertório de anticorpos no modelo equino. 78 f. Dissertação (Mestrado em Bioquímica e Imunologia) – Universidade Federal de Minas Gerais, Belo Horizonte, 2000.
• SUNDBLAD, A. et al. Characteristic generated alterations of autoantibody patterns in idiopathic thrombocytopenic purpura. Journal of Autoimmunity, n. 10, p. 193-201, 1997.
• TALHAM, G. L. et al. Segmented filamentous bacteria are potent stimuli of a physiologically normal state of the murine gut mucosal immune system. Infection and Immunity, n. 67, p. 1992-2000, 1997.
• VASCONCELLOS, R. et al. Genetic control of natural antibody repertoires: I. IgH, MHC and TCR beta loci. European Journal of Immunology, 28, p. 1104-1115, 1998.
• VAZ, N. M. et al. Immaturity, ageing and oral tolerance. Scandinavian Journal of Immunology, n. 46, p. 225-229, 1997.
• VERDOLIN, B. A. et al. Stabilization of serum antibody responses triggered by initial mucosal contact with the antigen independently of oral tolerance induction. Brazilian Journal of Biological and Medical Research, n. 34, p. 211-219, 2001.

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Chapter 2.5 – Disconnected immunopathogenesis

Nelson Monteiro Vaz

From black boxes to self-conducting

In a sincerely unpretentious way, I will present a theory about immunopathogenesis that has a connection with what has been put here, until now, that is, consistent with this “historical-systemic” view of Biology. I will propose that a break in the integrity of the immune system, in such a way as to allow a part of the system to acquire a stable, but partial dynamic, more or less independently of the global system – a somewhat spurious independence – is a mechanism that generates immunopathology.

Initially, we will move from a stimulus / response view to the idea of self-conduct (“conduct-Eigen”, Eingen-behavior), proposed by Jerne (1974), in the theory of the Idiotypic Network. The traditional way of thinking about Immunology works with inputs and outputs (inputsand outputs, stimuli and responses), that is, imagine a “black box” in which antigenic stimuli enter and specific immune responses come out. A black box is an aid to creative imagination. If you ask a 7-year-old child to design a potato peeling machine, he will design a box with an inlet tube for unpeeled potatoes and an outlet tube for peeled potatoes; inside, she imagines some mechanism, to be described, that peels the potatoes. When designing a dam or something equally complex, an engineer may want, at some point, entrance of a high voltage direct current and exit of a low voltage alternating current. He draws a black box stipulating this; later, it will detail its interior properly. The problem, as Gregory Bateson recalled, arises when we forget that the black box was invented by us, and we think that it belongs to nature, to natural mechanisms. In Immunology, we make this mistake, and think of the organism as a black box, into which we introduce antigens and from which specific antibodies emerge.

This is a mistake that we must correct. In fact, we want a mechanism that is not “inside” the organism, but that is part of it, in direct relation to its operation, but we get confused because we put this mechanism in relation to things outside the organism. According to the double vision developed several times in the texts that precede this, we must keep it clear that there are two domains of description that are separate: one in which we describe the physiology of an immune subsystem that is part of the organism; another domain that describes the interactions of this system, of this global entity with its environment. When we fail to see that the “medium” in which the immune system operates is the organism of which it is a part, we get confused. The immune system is in interaction with several other subsystems of the body, such as the nervous, endocrine and vascular systems, but it is not in interaction with the environment in which the organism lives, which is a meta-medium, which remains inaccessible to the immune system (Figure 18 ).

Figure 18  The immune system as part of the organism.

This misunderstanding could have been corrected when Jerne proposed the existence of anti-antibodies, which created a link between immunoglobulins and forced us to seek a certain organization for this network of relationships. In general, immunologists did not accept, or did not understand, the fundamental aspects of Jerne’s proposal. One of them is the issue of self-states (Eigen-states), the idea that the system, when operating, does not roll like a perfect sphere, but in leaps, as would a multifaceted polyhedron that can only move in certain directions; or as a mobile that has many possible states, but that obeys several restrictions of change, that channel its displacements.

Heinz von Foerster, who was a very interesting physicist, concerned with the autonomy of the systems, exemplified the idea of self-states with “self-referential phrases” (Figure 19). He asks that the dotted line in the sentence then be filled with words that make the sentence true. If we do this, empirically, we will find that, in this example, adapted to Portuguese, filling the gap with the words “thirty-two” or “thirty-four” makes the phrase true, that is, with the use of “thirty-two”, the sentence effectively changes to thirty-two letters. In addition, with “thirty-four”, it has thirty-four letters; but the words “thirty” or “thirty-one” don’t work. So, this little system has two self-states; others can be constructed so that they have only one, none, or several Eigen-states. They are local rules that satisfy themselves. The immune system must contain a huge variety of self-states, all defined by the structural dynamics of the system itself.

Figure 19  A self-referential proposition with two “self-states” (Eigen-states), adapted from von Foerster, 1984

The proposal that there are anti-antibodies has consequences that may not be immediately evident. By proposing that all antibodies are autoantibodies because they all react with other antibodies, Jerne (1974) invalidated, perhaps inadvertently, the entire class of autoantibodies. Thus, if all antibodies belong to that class, it is no longer a special class of antibodies; the prefix “auto” becomes superfluous. If all antibodies are autoantibodies, then no antibody is an autoantibody. There are no more autoantibodies!

In addition, if there are anti-antibodies, there are also anti-antibodies and so on, creating an infinite regression. The system would not be stable if there were no “closure”, an “enclosure”, a restriction of these reactions by which it, so to speak, bites its own tail. Jerne did not expand these notions, but we did so in a text published shortly after his proposal. Our text, however, remained perfectly ignored (VAZ; VARELA, 1978). The idea of autoantibodies, in short, implies the notion of operational closure.

Despite this flaw, Jerne had a remarkable intuition and predicted things out of his time. In a 1984 text, he predicted what I am proposing now; he said that: “mice may not express autotoxic horror, but they certainly express – with forgiveness of the word – horror monoclonicus” (JERNE, 1984), that is, a statement in defense of clonal diversity. He predicted that there was something pathological about reducing the diversity of immunological activity, something that not all immunologists have realized yet, but which is very important. So, based on everything we’ve discussed so far about the physiology of a true immune system – more so, based on this importance that I attribute to the stability and constancy of the reactivity of natural immunoglobulins – my hypothesis is that the immunological pathology emerges when the stability of the relationship between the immune system and the organism is broken. This is due to a loss of wealth of connections, an incompleteness that appears in the system. And a common way in which this incompleteness develops, in immunological jargon, is through “oligoclonal” expansions of T lymphocytes, that is, by establishing a suboptimal clonal diversity between the lymphocytes. This is what I propose as a common source of immunopathogenesis.

Immunopathology and oligoclonality

It is, in a way, ironic that immunologists have been intensely dedicated to the study of the amount of specific antibodies (or activated T lymphocytes) formed in each situation, and also to the study of their affinity (avidity) for the specific antigen, but have totally left aside the diversity of lymphocytes involved in each of these situations. In the traditional view, it would appear that having too many lymphocytes, each of which is moderately activated, would be equivalent to having a few intensely activated. However, the first situation, a large diversity of moderately activated cells, probably corresponds to physiological situations, while the second, few very activated cells, may well be involved in a wide variety of pathological situations. Oligoclonal expansions of T lymphocytes are at the source, both from a series of experimental, allergic and autoimmune immune lesions, as well as from numerous clinical conditions, including congenital abnormalities. What I am saying is that immunopathology can derive from the physiological operation of the immune system and not be imposed from the outside in. I will give some concrete examples where this happens.

The first example is a picture of congenital primary human immunodeficiency, called Omenn syndrome, for which models in mice have recently been developed (LEAVY, 2007). This syndrome depends on mutations in Rag-1 or Rag-2, which prevent the recombinations necessary for the generation of lymphocyte receptors (BCR and TCR); the child is born lymphopenic and with a T oligoclonality, a very high level of IgE and an intense eosinophilia. While the term lymphopenia refers to a reduction in the number of lymphocytes, the term oligoclonality is related to a reduction in the clonal diversity of these lymphocytes. Those few remaining lymphocytes expand a lot, and the pathology is a result of this abnormal expansion.

There are hundreds of examples in the literature, both clinical and experimental, that associate immunopathology with oligoclonal expansions of T lymphocytes. This occurs in the transfer of lymphocytes to lymphopenic organisms, such as, for example, in human bone marrow transplants; it is even more pronounced in transplant-versus-host reactions, which can complicate these transplants; many autoimmune diseases, atherosclerosis and liver and skin diseases; AIDS and cancer; and, significantly, in normal aging. There is evidence for large oligoclonal expansions of T lymphocytes, mainly CD8, during aging, both in humans and in other animals, and there is also evidence that these expansions are related to viral infections, such as the respiratory-syncytial virus (RSV) and influenza. These clonal expansions may be part of the loss of immune flexibility in senile organisms.

The thymectomy of newly born mice, as learned in the history of Immunology, generates immunodeficient animals. This is because the mouse is born in a still very immature state. The same operation performed a week later no longer has these effects, because the thymus has already sown the periphery of the organism with a great diversity of lymphocytes. If, however, thymectomy is performed three days after birth, many animals develop autoimmune disorders, as investigated repeatedly by Sakaguchi and colleagues (SAKAGUCHI, 2006). These disorders occur when lymphocytes expand with a suboptimal lymphocyte diversity, which was exported to the periphery during the first three days of life. It is another experimental model of what goes on in human Omenn syndrome. This phenomenon has become known as “lymphopoesis stimulated by lymphopenia” and it is said that lymphocytes, under these conditions, exhibit a “homeostatic proliferation”.

There are probably several mechanisms by which this situation can be established, but I wanted to give an important example: situations in which the lymphocytes are activated without the need for processing / presenting peptides. This occurs when, randomly, T and B lymphocytes start to interact by direct connection between their receptors, that is, when BCRs (immunoglobulins) in B lymphocytes interact directly with TCRs in T lymphocytes (TITE et al., 1986). Under usual conditions, B lymphocytes interact with epitopes that are conformational details of the surface of antigenic molecules. These determinants are destroyed as soon as the molecule begins to be cut into intracellular vesicles. T lymphocytes, in turn, interact with peptides generated in this processing, which may not be expressed in molecules in their native form. Although some peptides can be “immunodominant”, many different peptides are simultaneously presented after conjugation with MHC products. In other words, the processing / presentation of peptides pluralizes the possible lymphocyte interactions. This, however, does not happen when direct T-B interaction occurs and T lymphocytes can expand in an oligoclonal way (VAZ; FARIA, 1990).

Many immunologists would build experimental models, in which transgenic mice were manufactured to contain only one lymphocyte clone, and I want to refer to experiments by Juan Lafaille’s group, in which a mouse was created that has only two clones: a clone of B lymphocytes and a of T lymphocytes, with known reactivities. Injected with a conjugate of the two proteins to which these lymphocytes react, these animals form an amount of IgE hundreds of times greater than normal mice, that is, an extreme oligoclonality is associated with an extremely intense IgE synthesis. Significantly, the adoptive transfer of normal, polyclonal T lymphocytes to these animals, proportionally decreased the synthesis of IgE (DE LAFAILLE et al., 2001).

This is very strong experimental evidence of what I am saying. But can we say that this occurs in natural situations? Apparently, yes. In Chagas’ disease, for example, about 80% of patients have an indeterminate form and 20% have a severe form, with cardiac and digestive manifestations. Tested against extracts of epimastigotes in immunoblots, the sera from these two types of patients appear to react with the same antigens. However, when these sera are tested on lymphocyte cultures from the patients themselves, or patients from the same group, it is noted that sera from patients with the severe form (cardiac) stimulate the proliferation of T lymphocytes. Much more strongly, proliferation occurs even in culture conditions in which the processing and presentation of peptides is blocked (by colchicine), that is, it is a direct interaction of antibodies with T lymphocytes (GAZZINELLI et al., 1988a).

In schistosomiasis, it is the opposite: it is patients with the indeterminate (intestinal) form that form antibodies capable of stimulating their own T lymphocytes (GAZZINELLI et al., 1988b). It is difficult to compare the pathogenesis in schistosomiasis, which depends essentially on the formation of granulomas around parasite eggs retained in the lung and liver, with the pathogenesis of Chagas disease, which is related, for example, to inflammatory phenomena in the myocardium. These examples are, however, sufficient to point out common mechanisms of interference with normal immune activity. In both cases, the pathogenesis depends on defective forms of connectivity between lymphocytes. But direct stimulation of T lymphocytes by B lymphocytes is not pathogenic in itself; other factors seem necessary for pathogenesis.

It is perfectly possible to reconcile recent results on immunological dynamics with the hypothesis about the relevance of pathogenic oligoclonality. We know, for example, today, that severe forms of schistosomiasis in mice depend, fundamentally, on the reactivity to peptide 234-246, generated from a protein present in the secretions of S. mansoni eggs, which is capable of causing a huge clonal expansion in T lymphocytes that exhibit TCRs with restricted types of alpha and beta chains (FINGER et al., 2005).

In reality, the situation is far more complex than it appears. Female mice infected with S. mansoni become infertile: they generate few chicks and kill the few that are born, and the transfer of soluble anti-antigen antibodies from S. mansoni eggs to normal female mice significantly reduces their fertility (AMANO; FREEMANAND; COLLEY, 1990). Why? We do not know. We can deduce, however, that there are physiological interactions in which these immunoglobulins intrude, which we, as human observers, label “anti-schistosoma antibodies” and that these interferences result in infertility.

After all, this is an idea that belongs to the times that are coming, and there are already several texts in the literature suggesting the importance of lymphocyte oligoclonality in immunological pathogenesis (WU et al., 2004; BACCALA; THEOFILOPOULOS, 2005; KHORUTS; FRASER, 2005; KRUPICA; FRY; MACKALL, 2006). The December 2007 issue of the Journal of Autoimmunity brings a vast collection of articles on the importance of lymphocyte repertoires in immunopathology (AVRAMEAS et al., 2007). It remains, however, to connect this specialized knowledge with a broader biological view (VAZ, 2006; VAZ et al., 2006; RAMOS; VAZ; SAALFELD 2006).

New forms of therapy?

All of which I referred to as an immanent pathology of the immune system immediately raises questions about how to restore lost connectivity. Perhaps the only new form of immunological therapy introduced in recent decades, still empirical, as the vaccines invented until now have been empirical, but without serious side effects, is the intravenous injection of large doses of IgG, known as IVIg (from English, intravenous immunoglobulins). Idiopathic thrombocytopenic purpura, or, in colloquial language, a drop in the number of platelets that occurs for unknown reasons, is usually attributed to the appearance of antiplatelet antibodies, a form of pathogenic autoimmunity. The injection of large doses of IgG, collected from around 1,000 normal donors, has been able to improve, or immediately cure, these patients. It is possible that only a small portion of the injected IgGs is responsible for restoring normality, but so far we do not have the necessary knowledge to identify it.

There are also quite advanced studies in what has been called “T cell vaccines”, that is, procedures that trigger reactions against the activation of autoreactive T lymphocytes that are exercising a pathogenic activity. Some models suggest that this method can be highly effective, but, as in the previous situation, we do not know enough about the mechanisms of these variations.

How anti-infectious vaccines work

Since we are now talking about the subject of forms of therapy, I think it is appropriate to mention a couple of ideas about vaccines. Immune memory is currently believed to explain the effectiveness of anti-infectious vaccines. But, if so, there would be vaccines against all infectious diseases, because it is relatively easy to establish this secondary type reactivity. However, the desired immune protection is rarely associated with it. In reality, this shift to progressive reactivity often facilitates pathological reactions. The proposal that immunopathology, in general, derives from oligoclonal expansions, which break with the multiconnected balance of the immune system, may explain the action of vaccines in an innovative way.

In very simple terms, I propose that vaccines work by preventing oligoclonal expansions. It is known that only a portion, generally small, of people infected with a given pathogen actually gets sick. My hypothesis is that it is exactly this minority of individuals who, due to a combination of circumstantial factors, both genetic and epigenetic, react unbalancedly with oligoclonal expansions of lymphocytes. What vaccination would provide to these subjects would be a previous diversification (pluralization) of their way of reacting, avoiding oligoclonal expansions of lymphocytes, that is, vaccines do not work to enhance the immune memory, providing a progressive reactivity; quite the contrary, they diversify, pluralize the forms of reactivity of the organism and reinforce the stability of immunological activity, that is, healthy living. It would be that simple. There are many ways to investigate the truth of this proposal experimentally, and that is the value of scientific theories.

An investment in basic research

The only alternative we have to the current “target shooting in the dark” is a massive investment in basic research, which allows the investigation of deeper objectives and without this urgency that medicine – and, worse, funding agencies demand. But, for this investment to be made, there must first be a change in the way of viewing Immunology, the emergence of a way that highlights the organism and puts a greater emphasis on more “global” methods of analysis, such as those that allow analysis immunoglobulins all at the same time; or the receptors of T lymphocyte populations, such as spectratyping, the immunoscope and even more recent techniques – instead of looking at the expansion of antigen-specific processes.

It is possible to develop very general proposals that can also accommodate the traditional view of Immunology, that is, it is not a proposal that denies what is there, but of developments that bring Immunology closer to the important debates that are underway in Biology, as in Evolutionary and Developmental Biology. I am convinced that the immune system does not operate by producing specific antibodies against foreign materials, nor by increasing its memory of past antigenic encounters – although it has been possible to study immunological activity from this traditional perspective. I am also convinced that this “immune memory”, which allows for large oligoclonal expansions, is much more part of the pathology of the immune system than of its physiology.

Coda – In vain and in wine

I believe that there is a gap between yes and no, and the possibility of scientific action on it; between the technological triumphant yes with its hubris, and the no of discouragement that there is nothing to do. Once accepted, systemic logic is simply not acceptable: it is obvious. I believe, too, that there is a bit of intoxication, an unveiling of very wide possibilities in treating Immunology through this new perspective, which unties the Gordian knot with neo-Darwinism and denounces the simplism of medical causality. I fear, however, that what will emerge from this is no longer exactly an immunology of vaccines and antibodies, allergies and autoimmune diseases, but an aspect of the new way of treating the organism / person that we constitute as a unit in the biosphere. In general, this approach has no name. Due to its particularity, it will be initially adopted by a few.

References

• AMANO, T.; FREEMAN, G. L.; COLLEY, D. G. A reduced reproductive efficiency in mice with schistosomisia mansoni & in uninfected pregnant mice injected with antibodies against Schistosoma mansoni soluble egg antigens. American Journal of Tropical Medicine and Hygiene, n. 43, p. 180-185, 1900.
• AVRAMEAS, S. et al. Naturally occurring B-cell autoreactivity: a critical overview. Journal of Autoimmunity, n. 29, p. 213-218, 2007.
• BACCALA, R.; THEOFILOPOULOS, A. N. The new paradigm of T-cell homeostatic proliferation-induced autoimmunity. Trends in Immunology, n. 26, p. 6-12, 2005.
• BANDEIRA, A. et al. Transplantation tolerance correlates with high levels of T and B lymphocyte activity. Procedings of the National Academy of Science, n. 86, p. 272-276, 1989.
• BURNET, F. M. A modification of Jerne’s theory of antibody production using the concept of clonal selection. Australian Journal of Science, n. 20, p. 67-69, 1957.
• CARVALHO, C. R. et al. Indirect effects of oral tolerance to ovalbumin interfere with the immune responses triggered by Schistosoma mansoni eggs. Brazilian Journal of Medical and Biological Research, n. 35, p. 1195-1199, 2002.
• COHEN, I. R.; SERCARZ, W. Introduction: T cell degeneracy, Molecular Immunology, n. 40, p. 983, 2004.
• DE LAFAILLE, M. A. et al. Hyperimmunoglobulin E response in mice with monoclonal populations of B and T lymphocytes. Journal of Experimental Medicine, n. 194, p. 1349-1359, 2004.
• FINGER, E. et al. Expansion of CD4 T cells expressing a highly restricted TCR structure specific for a single parasite epitope correlates with high pathology in murine schistosomiasis. European Journal of Immunology, n. 35, p. 2659-2669, 2005.
• FOERSTER, H. von. Observing Systems. Seaside: Intersytstems Publications, 1981.
• GAZZINELLI, R. T. et al. Idiotype stimulation of T lymphocytes from Trypanosoma cruzi-infected patients. Journal of Immunology, n. 140, p. 3167-3172, 1988a.
• GAZZINELLI, R. T. et al. Idiotypic/anti-idiotypic interactions in schistosomiasis and Chagas’ disease. American Journal of Tropical Medicine and Hygiene, 39, p. 288-294, 1988b.
• JERNE, N. K. Towards a network theory of the immune system. Annals of Immunology, n. 125C, p. 373-392, 1974.
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CHAPTER 3 – Afterword – The way of listening

Jorge Mpodozis

By means of these final words, I propose to weave here a brief, or clear, conversation about the systemic concepts that are behind the discussions exposed here: the deepest, perhaps most vital and most necessary systemic concepts in all this discourse of systemic-historical Biology. And there is a set of concepts that I want to talk about and, perhaps, make them clearer.

Indeed, it has been common for a person to hear these concepts discussed so far and then appear to be unable to understand them clearly. And this is due to the way of listening, not the concepts themselves. When we discuss, for example, the concept of organization and structure and then hear what people say about it, it seems that we inhabit different worlds; what people hear and read as a result of our meetings and what they understand when they mention these terms – organization and structure, becoming, history – have such different meanings that we begin to doubt what we said or wrote.

And that has a lot to do, not with concepts, but with listening – because people hear these things from a transfusion of understanding that is not necessarily that of the person making the conversation. So, these things intersect or overlap with the understanding that each one brings, that has to do with a transfusion that, many times, is implicit, and not explicit, and that was simply formed during the daily life of cultural life and biological environment in which everyone lives. A framework of understanding is formed that gives each person a particular way of listening.

Thus, an additional effort is necessary in order to outline a way of listening and understanding that is common and that allows us to move forward. I believe there are many difficulties created by these different ways of listening. I believe that, although we talk about things that seem abstract or conceptual, thinking is always concrete, it always refers to operations, actions that we do or that can be done in the circumstances in which they may occur.

This is the content of thought. When someone shows an abstraction or proposes a concept, and declares it in discursive terms, it seems to be referring to something abstract, which exists in conceptual terms, removed from anything that has to do with you. I do not think, however, that this is the case. If we study Biology, we are doing experiments, and it is our temptation to talk about Biology. Thus, we will be involved in a discourse that is operational, that has to do with what is done and what can be done, and not with elements of another nature.

So, this concept of organization that seems esoteric and so central, in reality, is very old and substantial to thought, because it has to do with “distinguishing what remains in what changes”. Of course, because Aristotle, for example, realizes that we have many trees and that they are all different, so that I can say: “Here is a tree”? So, what I have are instances of realizing a generality.

Within this generality, all trees belong to the same class. But what does the tree class do? The philosopher would say that it is something principal and prior to particular trees, because the general is more important than the particular. And the exchangeable is less important than the permanent. That said Plato. However, we are talking about trees; let’s talk about living things.

Let’s talk about animals because they transform in an incredible way throughout their history. What remains when I distinguish an animal as a member of a class, say, an insect that goes through these metamorphoses; what am I distinguishing there? Look at this mammal, this mouse, this cat … What am I distinguishing? One way to change. The cat, or rather, its living in the “cat” is a distinction we make about how cats transform themselves in time.

This allusion to the way of conserving oneself and transforming oneself in one’s life is a fundamental point, because, in the case of animals, transformation is part of their existence. I cannot be surprised by the historical transformations of the organism because, the moment I stop them, it dies. What remains is how to change. How to understand this? How to understand it concretely, with the hands, because thinking is often done with the hands, it translates into operations, things that can be done or not. I would like to explain this with my hands: what remains is the way it changes. I can give you an example.

The other day, I asked a group of students to make a bell that would produce a single metallic sound, like that of a bell. I showed them a model, like these hotel reception bells, which we pressed with the push of a button to call a receptionist, and told them: produce bells. And, a few days later, my students arrived with two bells built in a very original way. One, for example, was made with a clothespin hammering against a metal plate; another was built with a soft drink bottle and a key inside held by a string that, when moved, promotes the sound of the key against the glass of the bottle.

This is a case like Aristotle’s, because here are these two objects, two instances of the realization of a certain entity that is in particular neither of these two things. What do these two things have in common? The interesting thing, in the case of these objects that are here and others, is that, if we look at them, we will see that, despite their components and the way they are made to be different, the form – Aristotle would say – is the same.

And what is this shape? There is something that generates a pulse and a resonant surface in both examples made by my students. It makes no difference what the pulsator is and what the resonant surface is. The relationship between these two things is what makes these objects what they are. So, the interesting thing about this is that the organization is common to the two bells (Aristotle used to say). What is the organization’s secret? Relationships, because the secret lies in the distinction of relationships between things.

Ah, it is evident that, for a certain object or entity to become a member of the class defined by these relations, the materials that make up that object or entity cannot be anything. When I have a doorbell, I will have something that serves as a resonator. That is, the constitution of one of these objects, as members of a given class, presupposes that there are components that materialize these relations. And from that point of view, not all things can be components of a given system. This is interesting.

There was something I pointed out to my students when I asked them to build bells. Where’s the sound? The sound is not on the bell, it is not a component of that system. What does the bell do? Produce the sound, draw attention. However, is sound a component of it? This seems trivial, but it is interesting. What I say about this system in functional terms does not help me to know how it is done. Snoring, the production of sound, does not take part in this: it results from the operation of it, but it is not a component of it. I don’t put sounds here: I put wire, wood, glass. The sound arises from the interaction of someone who can hear with the operation of that system.

The function is not part of the structure. And it is also interesting to consider the notion of organization – what remains in what changes. Ah, all the trees are instances of “tree”, as all these bells belong to the same class; therefore, they have an organization in common, and what I am distinguishing, then, is relationships. Interesting, because the distinction of relationships is also a “thing”. Distinguished relationships are as much a “thing” as the things that make it up, the components.

It is central to understand this when we are dealing with living beings for a very simple reason: because they are in continuous transformation. They are historical systems. So, the identity of the system is not in its material continuity, but in the relationships that define it. Relationships take place between components in space, although we could say, philosophically: relationships do not occupy a place in space.

I can therefore change the components, as in the story of the sword of Bernardo Ohiggins – the father of the Chilean homeland – who kept the sword in impeccable, brilliant condition. And when asked how he kept it, so, in such good condition, he replied: “It’s just that I’ve changed the handle and blade many times.” So, Bernardo Ohiggins’ sword has a historical continuity.

This happens in living. The car we use is taken to the mechanic to exchange parts. And a certain gentleman, too, had his heart replaced by another, and his identity did not change. And there are many other structural transformations that are possible without losing identity. This is particularly interesting when we have a dynamic, continuous system, because if we stop the dynamics of structural transformations in which the system goes through its operation, it disintegrates. I can take a picture of the system, or, say, freeze a cell. Is a frozen cell a cell? It has the potential to be a cell if it thaws; but the context of the relationships that make it a cell is not present.

If I stop the structural flow, I break the living being, its organization, because continuous structural change is constitutive of living beings as a system. I mention this because this question is very interesting, and I immediately put history as the central axis in Biology. This is nothing wonderful, exceptional, it does not result from great inspiration; it is not something we say to call attention to something rare, nor something that is accentuated in the Biology of Knowing, by Dr. Maturana, which has its history. We say this because we cannot say anything else. When we are dealing with living beings, we have to see their biology in terms of historical transformations.

And it is constitutive and inevitable for that very reason, because, if the animal is in continuous structural transformation and this is its way of organization, what will happen is that it will change, from the point of view of its structure. What is preserved in a lineage of living beings? Take ontogenesis: there is a cat, and it has a son, which is a cat. In distinguishing a cat, I actually distinguish a way of transforming itself into history. I cannot distinguish a particular moment, even though, comparing the particular moments, I can find the course of historical transformation that I call “cat”. The interesting thing is that, when we see transgenerational transformation, we see conservation as a way of transforming itself.

But this is also true of insects, with the wonderful transformations they go through. It is not just the moments, but the way to transform during history. Contemporary biology is reductionist in the sense that it is fixed in the moments, not in the dynamics of transformation and conservation. It does not include processes, but results; says that the gene contains the information; the process is not there, it is not respected.

Another singular issue is that in living there are two actors; there is structural transformation, but it does not take place in a vacuum: it takes place in a space of interactions. And thus, the organism’s way of relating to the environment also changes, because these relations are conditions of existence for this animal. If we stop this correspondence between the organism and its circumstances, the living being dies. Any time you leave the realm of possible or permitted relationships, the story ends. And what is possible, legitimate or allowed in “cat” living is different from what is possible, legitimate or allowed in “fly” living. Even though the fly and the cat are together, they are carrying out two different ways of living, in the same place, which seems to us to be the same, because the fly and the cat exist with us, in our space of existence, as equivalent things; but certainly, fly and cat live worlds that don’t really cross. Let’s say that, on a slate, during a scientific conference, there is a very erudite fly that enjoys lectures on Biology. The students present are in a conversation about Biology; but, and there on the blackboard, where is the fly? You are certainly not at a conference. So, although it seems to be the same place, they are different places that have to do with each animal. This place, its environment, appears with the life of each animal.

Returning to the bells, there is another issue that is relevant. If I press on a specific point, a noise is produced; if I squeeze other places on the same machine, there is no sound. But it’s not this finger of mine that determines what’s going on with the bell, because that’s a system, and everything that’s going on with that system is things allowed by its structure (eg, the fish in relation to its world, represented in Figure 2).

And, of course, in the case of living systems, this happens in a history of structural changes and with the conservation of the organization. Now, imagine if this bell was being built by the internal dynamics, which are replacing the cellulose molecules of this piece of wood and later adding bits of metal – it is difficult to keep a bell like that! It would be necessary to imagine a bell constantly changing its structure, in circumstances where what cannot happen is something that causes it to lose its correspondence with the world. When he loses it only once, he dies.

And how does that happen, how can you not lose your correspondence with the world under the circumstances that what comes from the world does not tell you what it has to be? Because it is not the finger that makes the bell sound. My finger cannot tell the doorbell what to do. The world cannot tell the living being what it has to do; it disturbs him, yes, but he cannot specify the nature of that disturbance. It is the structure of the system that determines what nature this disturbance is.

The same disturbance in different systems has different characteristics; so it is not up to it to decide what goes on in the system. So, this notion of adaptation becomes suspicious, of an animal “adapting” to a world and diversifying as it is subjected to environmental filters. How could this happen if the world does not drive, it cannot drive history. The external environment does not dictate the changes that occur in the organism, the animal’s world is what happens with it. His ontogenetic niche is established by his actions, interactions he establishes with his environment.

And the interesting point, which serves as a guide for our conclusions, are the questions. The questions we are asking here are different from the formal questions, the official ones of contemporary biology. This is due to the fact that this contemporary Biology is reductionist, as it does not consider history as a central issue. Nor does it consider organisms as systems.

What is happening, I think, is that we have a Biology inherited from Aristotle and, for him, the shape was by no means relationships between components: the shape was an external relationship, different from that, but that lives there and gives that’s what their properties are. However, which is, at the same time, separable: life, consciousness, the mind – seem separable from the structures where they occur. The mind lives there within that skull, but it is separable; it is not the result of operations that take place in living. Life, information, live there within the organism, but they are not about relationships between components, they are something different.

Why is this so? Aristotle can tell us, he is a philosopher. But, almost 2,500 years later, a biologist, who understands the structural question because all he does is play with the structure of living beings, to continue thinking in the same way is unjustifiable. In this explanatory path, a biologist refers to the central questions of Biology as abiological things, things outside of Biology: life, mind, spirit, information.

Do the genes have the information? What do they have? Are genes the vehicle of information? Is it the information itself? What concept of information is this? Speaking in terms of this metaphor is like saying that sound is a component of the doorbell system, whereas we have seen that it is not coherent. What Aristotle did not tell us is that organization and form have to do with relationships that are concrete, operational. This is what Aristotle did not tell us, because he was not in his world. And if Aristotle did not warn us about this more than 2,200 years ago, it is still not vehemently highlighted, at least in official biology, so to speak.

Although people who reflect on these things – because they encounter the problem – have said it in many different ways, and in many areas of biology, these conversations may only now be gaining relevance. But, as “no one is a prophet in his own land”, things take time to change. Anyway, I end these reflections with the desire to have made me a little more explicit about these notions of structure, organization, structural changes, becoming, conservation of the organization, structural determinism and the way in which these things come together.

It is not only legitimate to address these issues in this way, but inescapable. And when we do that, we find ourselves with new questions, which we have an obligation to try to answer. And I think something like this is what we are trying to propose.

About the authors

Nelson Monteiro Vaz, PhD, has a degree in Medicine from the Universidade Federal Fluminense (1963) and a PhD in Biochemistry and Immunology from the Federal University of Minas Gerais (UFMG, 1990). He retired as Professor of Immunology at the Institute of Biological Sciences (ICB) at UFMG (2004). Full member of the Brazilian Academy of Sciences and the Academia Mineira de Medicina. Founding partner of the Brazilian Society of Immunology and honorary member of the Portuguese Society of Immunology. He published about a hundred works, four books on immunology and one on poetry. He is also interested in epistemological aspects of immunology.

Jorge Mpodozis, PhD, is a neurobiologist who does not use the “information” metaphor; one of the only biologists who approach evolution without mentioning “selection”. Professor in the Department of Biology at the Universidad de Chile, he currently directs the Biology of Knowing laboratory. He studies perceptual and cognitive phenomena in vertebrates and is recognized for developing important epistemological reflections on the systemic / historical nature of organisms in their lives. Together with Humberto Maturana, he co-authored an evolutionary approach called Natural Drift.

Gustavo Ramos, PhD, has a bachelor’s degree in Biological Sciences (UFSC) and a PhD in Pharmacology (UFSC). He is dedicated to the understanding of immunoinflammatory phenomena from a perspective centered on the organism. In his doctoral project, he seeks to contextualize inflammation (regenerating the form) alongside more fundamental issues, such as animal development (generating the form) and healthy living (conserving the generated form).

João Francisco Botelho, MSc, has a bachelor’s degree in Biological Sciences (UFSC) and a Master’s in Philosophy of Science (UFSC). He is currently a doctoral student at the Universidad de Chile, where he develops theoretical and experimental works on the influence of epigenetic mechanisms on the development and evolution of animals.

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This book was edited with the font Chaparral Pro and Roboto, body 8-16. Soft pollen paper core 80g; supreme 250g cardboard cover. Printed at Gráfica e Editora Copiart in an offset printing system.

“Nothing in evolution makes sense except in the light of Biology”. By setting aside the answers to discuss new questions, “Where is the organism?” turns the vision of Biology and Immunology inside out and already expresses in the title the greatest concern and interest of the authors: the absence of a unified approach about the organism and living.

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PDF (English translation)

1. Meeting “Structural Determinism: Ontogeny and Phylogeny”, held in August 2006, Biological at the Federal University of Santa Catarina, Florianópolis, SC.

2. Regarding amniotic animals, that is, those that present, in their development, the formation of embryonic attachments, such as amnion, chorion and allantois, which make it possible for the development to occur entirely outside the aquatic environment – inside the egg, in this case, reptiles and birds; or the placenta, in the case of mammals.

3. Vegetative reproduction is a form of asexual reproduction, common in several species of fungi, algae and plants. It occurs simply by splitting and subsequent budding of the sectioned part, constituting itself as a new individual.

4. Epigenesis, here, is a term used in its original sense, that is, the reverse of pre-formation, a story that is constructed at every moment – genesis over genesis (epi + genesis). This metaphor of historical construction should not be confused here with the recent use of the term epigenetics, which refers specifically to the methylation and acetylation patterns of chromatin.

5. Neologism used here in order to transform the noun turtle into verb – actions, way of living, in a being. An allusion to processes.

6. Minelli (2003) draws attention to the fact that Evolutionary Biology is adult-centric: a Biology in which we try to understand simply adult life. Few species can, however, actually have an adult life, as rare species stop growing and then die when senescence begins. Trees, fungi, some reptiles and other examples grow indefinitely.

7. Neologism created by Maturana to refer to the theme through a verb that gives rise to actions, in this case, a typically human way of life.