At a conference marking the 150th anniversary of Darwin's book, "The Origin of Species", the physicist Dr. Erez Brown spoke about the place of the environment in shaping the genome of creatures. "Physiology and epigenetics must take responsibility for adapting to changes in the environment until genetics corrects itself"
Since the biologist Weddington coined the term "epigenetics" (in 1942), scientists have been studying the influence of factors outside the molecular structure of DNA on inherited traits. Epigenetics mainly focuses on chemical processes in which a phenotypic change occurs (in the traits expressed by the genes) without a genotypic change (a change in the sequence of letters in the DNA) occurring.
Dr. Erez Brown from the Faculty of Physics at the Technion spoke "from Darwin to EVO-DEVO" about the adaptation of yeasts to environmental changes imposed on them (changing the food substrate from sugar to galactose which is a less nutritious substance and vice versa), without the known mechanisms of evolution - natural selection - having the opportunity to control in process.
According to him, the yeast genes are being rewired, that is, a situation where a gene operates under a foreign regulatory system. "As a physicist, I wanted to think about it in this way: during evolution there is a master network of genes and there is a process of moving in different directions and we want to know from the combinatorial space which of them can survive and cause the creation of a new organism."
"We looked at how cell populations behave with unexpected challenges by rewiring them," Brown said. "We conducted an experiment and put forward two possible mechanisms that could explain the survival in conditions of reduced nutrition. The first mechanism is of course random mutations. This mechanism is possible but requires thousands of generations. Another mechanism is epigenetics. I would suggest a different order of events than the usual one - initially there is physical adaptation even if the conditions are less good, in the second stage - intergenerational epigenetic stability arrives, and finally genetic adaptation also occurs."
Naturally, Dr. Brown was asked by the audience if this was not a new Lamarckism and he replied: "Today's knowledge of epigenetics has shown that changes in the environment can cause a stable process. This has yet to be shown in multicellular animals. But epigenetics plays a much bigger role than we thought until now. Physiology and epigenetics must take responsibility for adapting to changes in the environment until genetics corrects itself."
On viruses that milk photosynthesis
Not only surface creatures suffer from viruses, it turns out that bacteria too, and especially marine bacteria - those that carry out photosynthesis and are responsible for about half of the oxygen production in the oceans and therefore also for a fairly high percentage of the oxygen we breathe.
Dr. Oded Beja from the Faculty of Biology at the Technion told the conference about a case of a virus that takes over a bacterium and for about four hours takes care of increasing the process of photosynthesis, in order to provide itself with food and reproduce. After a period, when many copies of the virus leave the cell and look for another victim, the bacterium is no longer interested in it and it is left to die.
These days, Craig Venter, one of the founders of the Human Genome Project, is conducting a search for the minimal gene. In a number of journeys that will eventually add up to circumnavigate the entire planet, once every 300 kilometers Venter stops and samples the water and records the genomes of the creatures found.
Beja and his team used the database created by Venter and found five types of viruses that attack photosynthetic bacteria. In his lecture, Dr. Beja described the sea trip he and his crew made in the Hawaii area. The scientists, from Israel and a number of other places in the world, took specific samples of these creatures in order to learn the details of the process.
The conference "From Darwin to EVO DEVO" was organized by the Lori Lockey Interdisciplinary Center for Life Sciences and Engineering at the Technion, on the 150th anniversary of the publication of Charles Darwin's "Origin of Species".
More news from the conference on the science website:
Prof. Ada Yonat: The principle of survival of the fittest also operated in the prebiotic period
Evolution continues vigorously
20 תגובות
Yair Shimron:
There is no reason for your surprise.
I responded to your comment 17 in which you found it appropriate to point out that "Hava Yablonka speaks explicitly about the fact that the phenotypic change precedes the genetic change..."
You said this to justify the use of the word Marxism and my answer referred to exactly this mistake!
Since Darwin and Mark did not know about genes - nothing they say can be confirmed or hidden by the fact that some change came before or after the genetic change!
What is known as "Marxism" (doing some injustice to Lamarck but that is not the issue here) is the inheritance of acquired beneficial traits as opposed to the development derived from the brutality of natural selection.
Nothing is taught axiomatically. This is true for all science and evolution in particular. Specifically - the topic of epigenetics is studied today by everyone who studies evolution.
Where do you get these insults from?!
We do not warn of anything as a firebrand, but we must point out the fact that no find that has been found to date is compatible with Hallmarkism (and Chava Yablonka also says this, but she hides it well - deep in the book so that all kinds of scope enthusiasts do not notice) and I allow myself to predict that no find Atidi will not coordinate Lamarckism - certainly not in organisms that multiply by sexual reproduction and in which the acquired properties are properties of tissues that are not sex cells.
Michael,
Your answer surprises me. She answers what I didn't say, and doesn't answer what I said. Obviously, the ancient evolutionists were not talking about genes. But when applying their principles to current knowledge, we also have to talk about genes.
As I argued in the previous one, today it is taught axiomatically that the evolutionary mutation is not related to the actions of the organism. That is, suppose a fish is in the process of changing into a land animal: if by chance, perhaps as a result of radioactive radiation, or ultraviolet radiation, or heat, or another factor, which is not specific to that organism but is general, common to the entire environment, a mutation is caused, which happens to be suitable for the development of the land animal from The fish, this mutation will buy a grip in this species. But the studies of evolution warn as a firebrand that we should not consider the Lamarck possibility: that is, the principle that was at the foundation of Lamarck's words, that the actions of the organism directly cause changes. Why was this idea rejected? Since no reasonable biological process has been found to lead a change in the organism to its offspring. But as I have already said twice, to the best of my knowledge no good evidence has been found even for the axiomatic idea of the head in the kippah. It was inferred as a sort of default. In my opinion the rejection of the Lamarckian possibility was too rash. Today there is quite a bit of biological knowledge that can support this idea.
Yair Shimron:
You do not speak to the matter.
The term genotypic change was invented long after Darwin did not know what genes were.
Lemark didn't talk about genes either.
It's just not up for debate!
Besides - the phenotypic changes it demonstrates are not those that create a match.
She saw them pass on to future generations in the laboratory - no, it's very likely that outside the laboratory they would even have become extinct, but even if not - it is, as stated, irrelevant.
In relation to randomness - if you define it that way, then you constantly find mutations that do not contribute to function.
In fact, the vast majority of them impair function and quite a few of them even kill.
to Michael Rothschild
Chava Yablonka speaks explicitly about the fact that the phenotypic change precedes the genetic change, just like in the article above, and as you know, she brings many additional flavors.
Marxism is a general term for the idea that there is a connection between the functions of organisms and the mutations that cause evolutionary changes.
I give up the word proof, and settle for the word evidence.
What is randomness? That is, the randomness of the evolutionary mutation in my opinion is defined by being not directly related to the functions of the organism, by its appearance following processes that are casual about the organism, such as radiation of any kind.
How will the randomness or reverse be shown? As they show everything in the sciences: observations, experiments, logic, theoretical summaries.
The claim of the randomness of the change-causing mutation is dictated to students at all levels as an axiom, even though in contrast to axioms such as the axioms of the plane geometry, regarding evolution there are possibilities for additional and less effective descriptions of the appearance of change-causing mutations.
By the way, the ancient Greeks knew that the earth was round and even calculated its radius long before the Zohar was written.
I don't know which quote from the Zohar you are twisting to draw your conclusion, but the Torah says completely different things.
http://daatemet.org.il/articles/article.cfm?article_id=4
To the anonymous user:
Your words are simply not true.
There was no scientist who made such a claim.
Since when - do you think science exists?
Do you even know what science is?
Yair Shimron:
So why did you use the word Marxism?
Chava Yablonka uses the word to describe a mechanism that is completely orthodox in terms of Darwin's definition of evolution - that is - changes that occur and become apparent through natural selection. She's just saying that in addition to normal traits that evolution has developed, it (maybe! She's not even sure about that!) has also developed mechanisms that multiply the frequency of mutations in stress conditions and perhaps even those that dictate mutations in regions of the genome that are a function of the type of stress.
Regarding the proof you require - as everyone knows - there are no proofs in science.
How do you define randomness?
How do you expect it to be proven?
What is clear is that all the proposed non-random mechanisms have been disproved.
Scientists in the past thought that the earth was flat (and yes they were scientists and we came to the discoveries thanks to them) and they were the majority, today almost everyone knows that the earth is round or oblong (according to taste) and so it was written in the Zohar book many years ago.
to Michael Rothschild
I also did not propose Marxism as Mark talked about, and in fact I did not propose any mechanism. I was talking about an idea, that is, the principle that has not yet been ruled out experimentally or observationally according to which, perhaps, there is some connection between the functions of organisms and the mutations that produce changes. In my opinion, the currently accepted explanations in the theory of evolution do not sufficiently explain the phenomena we see. For this purpose it is useful to remember that on average each gene has 20 proteins (25000 genes and about half a million proteins) which means that phenotypic changes are theoretically possible even before the appearance of a genetic change.
Also, you did not answer the claim that I did claim, that there is no observation or experiment that proved the claim of the randomness of mutation.
Yair Shimron:
It is true that Chava Yablonka invited the disruption you are doing to her words, but it is still disruption.
If you read her book (Evolution in Four Dimensions) you will see that she does not at all talk about the Lamarckism that Mark talked about (and she says so explicitly!).
According to me, she should not have used the term because it was clear that people would jump on it without reading her words, but apparently her consideration in the matter was not scientific but advertising.
To my father for comment 5:
Even the main mechanism currently proposed for the processes of evolution, namely random mutations that give their owners an advantage and as a result multiply in the population, has never stood up to any experiment nor any observation. According to Chava Yavlonka, the future of the Lamarcian idea is still ahead of him.
It's a shame I couldn't bring the graph, the graph shows that epigenetics adapted itself but at a much lower level than those creatures adapted to the existing conditions, he called it a new equilibrium. The weight value was at a much lower level when the yeast was fed galactose than glucose, so it is clear that if you ask them they prefer glucose, but even the less good substitute does not cause them to die 80% like in the beginning, but only say 20% and so there are XNUMX% that survive even though they did not pass Genetic changes (the numbers are my invention to describe what I saw, not necessarily what was in the original graph data).
The essential question that arises from the article and the discussion that follows it is, is it possible to influence the direction and speed of the genetic mutation mechanism, through
A change in the external conditions relevant to the mutation.
I think the answer to that is yes. This can be justified by the fact that if any mutation has an evolutionary advantage, this means that this mutation will result in a greater ability to produce offspring.
All this under one condition. And the condition is that the change in the external conditions is not too strong and sudden but one that allows evolutionary adaptation.
"Finally genetic matching occurs" - from the little that is in the article it is not clear why genetic matching occurs, what causes the matching, and what are the chances of the matching occurring. Apparently the epigenetic mechanism solved the problem.
While the research's contribution to understanding the importance of epigenetics is clear, it is not at all clear what the research's contribution is to evolution.
It is clear to everyone that Markian evolution would have solved many of the questions in biology. But science prefers the simple ways over the simplistic.
I would propose such a mechanism, the environment creates physical changes (for example, the sun changes the color of the skin), the change in skin color activates the genes responsible for the skin color so that the rate of mutation production in those genes increases, and thus it is actually possible to achieve the same effect in fewer generations.
As for Lamarck - indeed, Lamarck is also considered an evolutionary thinker, and if he was right, evolution would have used this mechanism as well, but the mechanism he proposed simply did not pass the scientific test.
Doss:
You can put whatever you want in the definition of evolution.
The goal of science is not "to find out what is included in the definition of evolution" but "what happened in reality". Capish?
If for evolution the very change is important and not how they were created, then Lamarck can also be included in the definition of evolution, because according to his method the development is from the simple to the complex and the whole difference is in the reasons for this, because Lamarck did not accept the idea of extinction.
Not true, because epigenetics also produces variation - for example in the expressions of genes, although not in the genes themselves and this is also an evolutionary mechanism. For evolution, the existence of the changes is important, not how they were created.
"Another mechanism is epigenetics. I would suggest a different order of events than usual - initially there is physical adaptation even if the conditions are less good, in the second stage - intergenerational epigenetic stability arrives, and finally genetic adaptation also occurs."
If this is true - there is no doubt that the hypothesis of evolution requires a significant correction.