Nail soup
The leading evolutionist spoke about the Multiverse and the anthropic principle
One of the world's leading experts on the origin of life and the most cited biologist of Russian origin Evgeny Kunin has published a book (The Logic of Chance: The Nature and Origin of Biological Evolution), in which it claims that the genetic code arose by chance, and the explanation of the origin of life is impossible without the involvement of the anthropic principle.
Kunin's scientific works have repeatedly been included in the "Progress" category, therefore "The Tape.ru" decided to talk to him about evolution, randomness and the multiverse.
"The tape.ru": You are engaged in comparative genomics. Please explain what is this field of science and how does it differ from bioinformatics and systems biology?
Evgeny Kunin: These are really very different fields of scientific activity. If they are represented in the form of Venn diagram circles, they will overlap significantly with each other, but also have significant unique parts.
What is comparative genomics? In a more or less narrow sense, this is, of course, a comparison of the structure of genomes and the detection of conservative and variable sites in them.
It implies attempts to draw conclusions from their structure and organization, analysis of the level of conservatism and calculation of the rate of evolution that they undergo, and so on and so forth. At the next stage, this leads to a reconstruction of the evolution process and an understanding of how everything happened.
What is bioinformatics? I hate that word terribly, but you can't go against the current. Bioinformatics is not a field of science as such, but a certain set of computer methods and algorithms that are used to process, roughly speaking, any biological data. If I, for example, process biological literature, extract some keywords from it and cluster articles, then this, in a sense, will also be considered bioinformatics. The study of some electronic microphotographs and their comparison, the invention of algorithms for storing large amounts of information is also bioinformatics, it's all necessary. But this is by no means comparative genomics or systems biology.
Bioinformatics is not a field of science as such, it is a set of methods and approaches.
And what is systems biology? Something like the ENCODE project?
Generally speaking, no one knows what systems biology is. Looking back, it seems that it would probably be better not to invent such a term at all. But it was invented, and it has already taken root.
What does ENCODE include? On the one hand, it implies a comparison of genomes, but on the other hand, more importantly, it includes what can be called the monstrous Russian word "transcriptomics" - that is, the most complete study of all transcripts of the genome, which has become possible thanks to modern sequencing technologies (determination of nucleic acid sequences). In a narrow sense, this is no longer genomics, but something that you can call systems biology.
Behind the words "systems biology" there is usually the idea that it is necessary to study an organism, a cell or a cell with a virus as a kind of system as a whole. But how exactly to do this, no one really understands. Thus, large-scale (high throughput) studies of something and combinations of such studies really fall under this umbrella. For example, the study of the complete transcriptome - all the matrix RNAs in the cell. What became part of the ENCODE project. Or the study of the proteome - all the proteins existing in the cell, together with all their modifications. So far, the existing Systems Biology implies not so much the study of some biological systems as a detailed description of their parts. Although, of course, it is already possible to build some models based on the data obtained in this way, but this is another question.
It seemed to me that the term "systems biology", in general, was coined in order to somehow name the work in which researchers, for example, are trying to simulate the work of a single cell.
Perhaps. Most likely it is. But if you look at the monetary equivalent, the reality of modern systems biology is that direct attempts to simulate the functioning of cells, tissues, organs, whatever, absorb only a tiny fraction of money. And the lion's share of them goes to research, which can only be considered as preparatory stages for this modeling. So there is a certain imbalance here, which may be eliminated after some time, when such a simulation of the cell's work becomes more realistic.
This summer "Tape.ru" wrote about the work in which, according to the authors, the most detailed model of a single cell was created. It calculated processes at the level of individual genes and enzymes. Now, in 2012, are such models just toys or do they have something to do with reality?
I don't want to offend anyone, but, from my point of view, so far this is a children's designer. It is argued that such models are necessary to understand how it all works. But if you can't manipulate them in a predictable way, then these are empty words. To learn how to make such models, it still needs to take a few more years.
Whether the specific approaches used in this article lead to this “temple”, I do not know, this is not really my area. To date, these models are unrealistic, and to say the opposite is still some speculation. But, undoubtedly, something like this should be done.
The advantage of such works is that they go in the direction of some kind of systematization and formalization in biology. Because now there is just a flurry of articles, the amount of data is increasing, and it is very difficult for even a specialist to understand something in them. At the same time, I recall the manifesto of Yuri Lazebnik, in which he shows that while biologists use the descriptive language they are currently speaking, it is impossible not only to understand the cell, but even in the device of the radio recorder. (See the popular retelling of the article "Can a biologist fix a radio receiver" – VM.)
I am very sympathetic to such things, I even try to do something in this direction, but I look at it (to paraphrase Einstein somewhat) like this: yes, you need to try to formalize literally everything that can be formalized intelligently, but no more.
In addition, it can also be formalized in different ways. After all, we can build a reasonable physical model, or we can act on the principle of a "black box". This is much less interesting, in my opinion.
I see. Let's get back to genomics. A few years ago, Darwin's book "On the Origin of Species..." turned 150 years old, 50 years of the completion of the consolidation of the synthetic theory of evolution and 15 years of the first comparison of complete genomes. During this time, as I understand it, the theory of evolution has changed a lot. In a sense, it is like a living organism - it has completely changed in parts, but in general it has remained unchanged. What has "fallen off" from Darwin's theory in these 150 years, and what is still left?
You see, what's the matter. Almost nothing "fell off" from Darwin's theory. Of course, a huge number of other ideas and ideas were added to it. Nothing could remain unchanged in the strict sense of the word in it, due to the fact that Darwin did not have a correct understanding of genetics. This is absolutely not a reproach to him, but it was. Therefore, in the literal sense of the word, nothing in the theory of evolution could remain unchanged.
Darwin was a man of genius precisely because he managed to build a kind of meaningful structure in the form of an air castle. He had no foundation, and yet he managed to understand that in essence the most important and only important thing in life is "descent with modification", inheritance with change.
In fact, the whole point of life is precisely that information is transmitted through generations with sufficient accuracy. I'm modernizing a little bit, but in fact, this is what is written somewhere in the core of Darwin's book.
This means that the basic information about the structure of the body is transmitted from generation to generation with sufficient accuracy, so that changes do not destroy its basis. At the same time, these changes occur often enough to be affected by what Darwin called natural selection. It is important to emphasize that natural selection is not a special phenomenon. This is something that arises from inheritance with change quite automatically. And Darwin understood this in general.
Although he didn't know what it was based on.
That's what I'm talking about, that's his special genius. He did not know at all what heredity was based on, he just understood that it could not be otherwise, and understood it correctly. And this principle has remained at the heart of understanding and cannot go anywhere, because it is inevitable. And, apparently, is the basis of all life. If they ever find another life, it will be based on the same thing.
In general, I imagine modern evolutionary biology as a soup made of a nail: yes, without a nail, of course, there would be no soup, but basically there is something else.
It just seemed to me that the most important thing that has happened to the very core of Darwinian teaching since comparative genomics appeared is the shift of the center of gravity from adaptation to randomness. To the fact that the authors of the synthetic theory of evolution in the 60s completely discarded.
Let's say carefully: they have discarded any role of chance in anything other than the occurrence of mutations. They assigned the whole role of chance to the occurrence of mutations. Indeed, if we single out one main aspect of the changes that have occurred with the theory of evolution, then this is probably exactly the case. In the language of physics, which I like to use, we have changed the null hypothesis. Now it consists in the fact that by default any changes that are fixed in evolution are neutral changes, that any adaptive value of any changes should be proved. Perhaps this is really the most important thing that happened. But, as you understand, any judgments about the most important things are subjective, and many other important things have happened.
I think another thing that is equally important for understanding evolution is the following. We biologists have discovered the world of microbes, including viruses. Darwin did not know about them in any meaningful sense. He knew that there was something like that, but he completely ignored this world in his picture of evolution. Just like the authors of the synthetic theory of evolution.
And this discovery of the world of microbes influenced the theory of evolution extremely radically. First, we now know that these organisms evolve in a significantly different way. Not completely different, inheritance with change, of course, is also present here. But they have a completely different dynamics of evolution. And secondly, they absolutely cannot be neglected when considering the evolution of any organisms. This is also an extremely important understanding, which neither Darwin nor any authors of the synthetic theory of evolution had at all.
All these wonderful people applied their models and principles only to animals and plants, and this is a very small part of biological diversity.
The anthropocentric tree of Haeckel's life.
That is, the idea of the tree of life, as Darwin understood it, has now changed a lot?
Of course, absolutely changed. And moreover, in a mathematical sense, it has ceased to be any kind of tree. In mathematics, a tree is still a binary branching graph, or at least a directed acyclic graph - that is, several of its branches can literally come from one mathematical point.
The online life story in the Ford Doolittle illustration.
Image American Association for the Advancement of Science
But we now understand, and I think it is not worth disputing, that nuclear organisms arose as a result of the symbiosis of two cells. And thus, in the language of graph theory, a cycle appears in our tree, which means it is not a tree at all. Moreover, this symbiosis was not the only one, as you also know very well. Plants, for example, became plants as a result of the acquisition of chloroplast. Why go far? Almost all insects carry intracellular symbiotic bacteria, in many cases they are absolutely necessary for the existence of these organisms. The whole idea of the topology of this "tree" has changed.
So you want to say that the picture has also changed for plants and animals now?
Let me just tell you a banal thing. The mammalian genome consists of approximately 2/3 of the remnants of viral genomes. And the genome of plants, such as corn, is 90 percent complete. To ignore this fact and at the same time consider their evolution, to put it mildly, means to consider it incompletely.
What should now be on the corresponding page of the "Origin of Life" instead of this famous picture?
It should be a kind of network of gene exchange, genomes, genome mergers, and so on, from which tree-like formations actually grow in places.
Is there no such border in this picture where one could say: here the network ends and the tree begins? Or is such a statement of the question meaningless?
No, it makes sense. There are just a lot of such places, and they are located in different parts of the living. For example, I doubt that it is possible to construct a meaningful unambiguously resolved tree of all nuclear organisms. You can, of course, build a tree of life for some plants or animals, but you need to understand that these are still terminal branches.
Similarly, it is possible to build flu evolution trees over the past hundred years. All this reflects evolution very well, but when we go deeper, for example, trying to build a tree of the evolution of all bacteria, it makes little sense.
As I understand it, in practical terms it looks like this: if you build a tree, for example, first by the sequence of ribosomal RNA, we get one topology of the evolutionary tree. If by another sequence (also very important, for example, the sequence of aminoacyl-tRNA synthetase), then a completely different topology is obtained. It turns out that it is impossible to catch the "root" of this tree, it turns out that at some stage there was a whole pool of genes that everyone freely exchanged.
You all speak well, I would just not use the words "absolutely", since with a completely free exchange, it is generally impossible to talk about organisms. The pool of genes really existed and still exists. It is separated by barriers that are permeable to different genes to varying degrees.
But if it is impossible to find this root, simply because it did not exist, does this not mean that with the help of comparative genomics it is impossible to look into the history of life to the depth where this pool existed? It is clear that this is much deeper than any paleontological data.
In general, there are all sorts of transformed rocks and traces of life about three billion years old. So some aspects of what happened at that time can be seen in the paleontological chronicle. It is very difficult to see the organisms directly and it is impossible to see what they were like from the inside, but some traces can be found.
As for comparative genomics, it can really look very far. Namely, deeper than the common ancestor of all existing organisms. The question is, what can she see there?
What can she see if we talk about LUCA, the last common ancestor? How well do we know him? I take it it's pretty good?
How can I tell you? That's both good and bad. In a sense, it's not bad: we can make very precise statements about what was in it. It had a broadcast system that was very slightly different from the modern one. There were some metabolic processes in it, it is not necessary to list them exactly, but some metabolic pathways clearly existed in it. In it, in some form, although it is already very unclear in what form, there were some membranes.
Was it photosynthetic?
No, of course not. This process arose a long time ago, but noticeably later. And more than once.
Something else is more interesting. When you and I start talking about this very LUCA as an organism, as something that can be taken and grown in the form of a colony on a Petri dish, as is customary in the experiment, you need to be very careful, this could never have happened. This LUCA could well be a community of microorganisms that emerged from some simpler stage already as a community. This is a perfectly reasonable way of looking at things.
If with the help of comparative genomics we go deeper and deeper into the history of life, we begin to compare sequences with more and more complex methods, we no longer analyze sequences of nucleotides, but some common protein folds, then we come to one of the most difficult problems in biology in general.
I mean the question of the origin of proteins. How did it happen that for the most primitive protein synthesis systems to work, the existence of proteins themselves is necessary, and they belong to different evolutionary families - that is, they have already gone through a long process of evolution?
The question is clear: a chicken requires an egg, and an egg requires a chicken. Short answer: we have no idea about it. This is really a gigantic problem and a paradox in the true sense of the word.
Of course, we can't help but think about things that we have no idea about, but that are infinitely important and interesting to us. And not to build any models, no matter how speculative they may be. Moving on this shaky ground, we can say the following.
What emerged at the very first stage of life or some kind of pre-life is the world of RNA, where there were no proteins or, in any case, no proteins were encoded by anything, but there were only RNA molecules that somehow performed all functions. They not only reproduced, replicated, but also catalyzed all the reactions that are necessary for this. One RNA replicated the other. I'm not going to get into the rather complicated chemistry of this case right now, but logically it's almost the only possibility.
If we allow this, then we begin to think about how some proteins could fit into this case? The answer is given to us: they fit into this business in the most serious way, and very early in the scale of evolution. How could this happen?
Amino acids and even peptides, that is, amino acids connected in small chains, are quite easily formed abiogenically, without the participation of living organisms, and they have some pretty "good" properties - they can help reactions that catalyze the so-called ribozymes - catalytic RNAs. And this idea develops along approximately the following path: evolution went by attracting (at first without any coding) amino acids, then peptides, or both amino acids and peptides into this world of RNA. And something emerged that could serve as an analogue of transport RNA, that is, RNA molecules that bound to amino acids and performed some catalytic functions better than others that did not bind. Something like that.
The structure of the large ribosome subunit. RNA is colored brown, proteins are blue.
It can be seen that RNA plays a central role in the structure, and proteins are only "decoration".
Image of Yikrazuul
In my opinion, the existence of the RNA world has a fairly solid support in the very structure of the ribosome.
Yes, of course, this is one of the main arguments, but there are others. In general, the fact that protein synthesis in each cell actually performs RNA, and proteins in this process perform only an auxiliary role, is a weighty argument in support of the RNA world. But there are others.
Here you mentioned such proteins, aminoacyl-tRNA synthetases, which attach certain amino acids to certain transport RNAs. In other words, they ensure the work of the genetic code, the coding itself. These proteins are common to any living organism. But if you delve into the details for a second, then there are two basic unrelated families, one of which is responsible for some ten amino acids, and the other for others. All of them, as far as we know, were already present in this very LUCA.
Now, if we build some kind of evolutionary tree for the central domains of these enzymes, we will see that the specialization of these aminoacyl-tRNA synthetases was preceded by a long evolution of the proteins themselves. That is, at first there was a very serious evolution of these proteins, and only then they became, in fact, the basis of the genetic code. This suggests that the evolution of proteins took place even before the system of their synthesis became what we know it now. And it was based on RNA.
Now the most interesting thing is how to move from this, in fact, to the emergence of the genetic code? Many people, including us, tried to build some schemes of how this could happen. They imply the existence of a certain large RNA enzyme, which at some point switches to protein synthesis, and some other RNAs become matrix RNAs.
None of these models seem convincing to me. We know that protein synthesis has somehow arisen, but we do not have a convincing sequence of stages.
In this regard, of course, there are ideas that I, for example, have to take seriously. The idea that quite complex systems (of course, not all elements at once) could arise purely by chance.
This happened, mind you, only once - all cellular life has a single origin, and in particular the genetic code and the translation system. When we know that something has a single origin, then, naturally, a window opens for a large role of chance. It has arisen and has arisen. Winners are not judged.
And here we come to the question that I have saved for completion. I want to ask about what very different people scold and praise you for. I mean linking the accidental origin of life with the anthropic principle. It is interesting to read the reviews of this article of yours, because somehow a lot of creationists were excited by this idea.
In my opinion, there is a very serious scientific content here and there is also a rather serious aspect of sociology in science. They should be separated.
From the point of view of scientific content, I believe that the extremely poorly named position, which we call the anthropic principle, is indeed absolutely necessary for understanding the origin of life. In the sense that it is quite obvious that this phenomenon is rare. In order for it to arise, a combination of many random circumstances is necessary. And it does not depend on at what stage we can draw the line between a more or less random combination of circumstances and biological evolution proper.
This limit may be lower, it may be higher, but it exists. Many questions about why the part of the world around us is arranged the way it is arranged can only be answered in this way: because if it were arranged differently, there would be no one to ask these questions. This does not mean at all that there are any goals in evolution, that you and I, as a species of Homo sapiens, have any special significance. Nothing like that.
The fact is that complex systems have arisen and they may not arise in all parts of the universe. Therefore, there is only one answer to many questions: if history had gone a little differently, if the parameters of our corner of the universe had been a little different, there would not have been this phenomenon called life. It just wouldn't have happened and that's it. In this part of the universe.
In itself, this idea in the framework of the leading modern cosmological theories seems to be highly rational. Such an idea, of course, is completely free from any ideas about any goals of evolution, ideas about any special meaning of Homo sapiens. It just doesn't exist. And therefore the expression "anthropic principle" is extremely unfortunate, and more serious people, generally speaking, prefer to talk about what is called "Observational Bias" (observer error). Sounds a lot less sexy, but...
But there is no translation in Russian, apparently.
This translation is not easy. It means that what we are observing limits those versions of the story that could lead to this. That's what it says here, and not something esoteric at all. No way!
As for creationists, they are cunning, clever people, but stupid, because they grab at everything that somehow deviates from the usual scientific explanations. For everything that attracts randomness in some meaningful way, for everything that says that some complexity could arise spontaneously, for any statements that seem unusual to them. They immediately say, "Aha! This is what we have always talked about, and you just slip some kind of rationalistic basis under it, which is not there. It's just that everything is made by the Creator, and the whole story." In the old way, it was simply called distorting, cheating.
Relic microwave radiation is evidence of the initial stages of the existence of the Universe.
Its structure is considered one of the main arguments in favor of the theory of inflation and the Multiverse.
NASA Image / WMAP Science Team
But they are based on your calculations. Based on the fact that the occurrence of life in this particular observable universe has a probability of about 10-1018. That is, in a simple way, it is almost impossible.
These are calculations, as they say, on the back of the envelope. Nevertheless, by a dozen orders of magnitude, they are not so bad, maybe. Indeed, the origin of life is extremely unlikely. Only these critics forget to quote from the same article that, according to modern cosmological theories, in an infinite universe it is at the same time inevitable. Despite the fact that at any point it is extremely unlikely.
We already know in advance that we are at the point where this happened. This is the only anthropic principle. In fact, in the context of the idea of an infinite Multiverse (what is called the Multiverse), this principle becomes absolutely trivial.
Critics reject the Multiverse hypothesis as unfalsifiable and, therefore, unscientific.
This is a very difficult question. Let's just say that the question of falsifiability and its necessity is a very difficult question.
But you can say a simple thing. The multiverse hypothesis was not invented at all to explain the origin of life or the emergence of man. She has nothing to do with it. It was put forward for purely rational physical reasons, to explain the heterogeneity of background cosmic relic radiation, for which people received the Nobel Prize, and other equally serious data. It is to explain these data that modern versions of this hypothesis have been invented. Opposition to these ideas undoubtedly exists in physics itself, but not to chatterers on Amazon.com try to refute it.
Is it worth fighting creationists, clerics, people who are in opposition to the theory of evolution, or is it useless for them to try to explain something? Your colleague, Mikhail Gelfand, is trying to do this - he participates in TV shows, for example.
I look at it this way: as soon as they try to invade the spheres of science or education, then yes, of course, they need to be thrown out of there. Religion should not be fought, but its attempts to invade the broad spheres of public consciousness, especially in any science, yes, should be fought.
At the same time, in my opinion, you should not try to refute their arguments - you will never convince them anyway. Rather, we need to explain as intelligently, interestingly and rationally as possible what we can understand, and point out what we are not able to understand yet, but we hope to do it in the future.
Many believe that now, in terms of the influence of creationists, Russia is in a bad way approaching America and sometimes even ahead of it. If, relatively speaking, Orthodoxy courses are introduced in our school, then in America people who deny evolution are going to Congress.
Yes, in the USA it is present on a large scale. But at the same time, you need to understand that we have hundreds of good universities here, and God forbid there are three in Russia. There is some difference. The integration of science into life is greater here, despite all these phenomena of obscurantism, which are really visible at every step.
Alexander Ershov talked
Portal "Eternal youth" http://vechnayamolodost.ru
03.12.2012