Prof. Naama Barkai from the Weizmann Institute of Science discovered when the genes are ready to go on adventures, and when they prefer to avoid changes * This Sunday, at the Weizmann Institute, Prof. Barkai will receive the Helen and Martin Kimmel Award for Innovative Research, which is accompanied by a research grant of one million dollars over five years
The courage to experiment is one of the engines that drive evolution. Living cells are, from this point of view, a wonderful field of experiments, where different molecules influence other molecules and sometimes cause them to act in new ways. When these molecules are genes, or proteins, such experiments can lead the cell, and sometimes the entire organism, on a fascinating evolutionary journey. Prof. Naama Barkai from the Department of Molecular Genetics at the Weizmann Institute of Science recently examined various aspects of the control processes that affect gene expression, the process by which the cell creates proteins based on the information encoded in the genes. The proteins activate the life processes, and changes in their structure, resulting from changes that can occur in the genes, may give the cells new abilities and survival advantages on the one hand, but also cause disease and even death, on the other hand.
Example question: When does evolution progress rapidly? When can genes change, in function or expression, easily and carry out experiments that may endanger the organism, and when - and if - genes strictly maintain their structure? This basic question is of particular importance, against the background of the well-known phenomenon of conserved genes in evolution, that is, genes whose similar versions are found in both simple and evolved organisms, starting from yeast, through worms (nematodes), flies, and plants, and ending in humans. It is clear that the genes conserved in evolution play basic and universal life functions, which are shared by the entire animal world, so that changes in them cause the organism to die or to be unable to reproduce. On the other hand, of course, without experiments and changes, evolution will not move forward. How, then, did evolution constrain the genes to maintain their structure? What exactly protects them from the genetic experiments that are constantly taking place in other areas of the genome?
Prof. Barkai and the members of her research group discovered the "law of risk distribution" of evolution. It turns out that the more the gene encodes a protein that is essential and universal, the less likely it is that its starting segment (promoter) contains the TATA genetic "expression" (a repeating sequence of two certain bases in the genetic code). This section plays a central role in the expression processes of the gene. The scientists discovered that when the "expression" TATA is found in the initiating segment of the gene, the level of risk that can be taken, as a result of making changes in the expression levels of this gene, is greater. In other words, it is a kind of definition of risk levels, similar to analysis
Risks and opportunities performed by capital market analysts. When the cost of error is large, our tendency to take risks in this area is small. When the cost of error is negligible, we can try to realize great chances, even at the cost of taking a high risk. Evolution, it turns out, discovered this principle millions of years before Wall Street and Ahad Ha'am.
In another study, Prof. Barkai and the members of her research group examined an evolutionary experiment that nature sometimes performs in living cells. It is a spontaneous doubling of the entire genetic load. The same phenomenon affects two species of yeast in a completely different way. The yeast from the species "Candida" (known, among other things, as a cause of death in AIDS patients), which underwent genome duplication, thrived at a rapid rate, as did the yeast from the species "Cervisa", which has the double genome, but these yeasts (from the species "Cervisa") learned as a result of the genetic experiment "a new trick : They have demonstrated the ability to grow and thrive without oxygen.
Prof. Barkai and the members of her research group examined this phenomenon and found a genetic evolutionary expression for it. They examined 50 genes that play a role in the metabolic processes of oxygen consumption in both yeast species and discovered that a certain genetic segment, responsible for their expression process, underwent a change during genome duplication. This change dramatically affected the expression of these 50 genes, and probably also the oxygen consumption characteristic of one of the yeast species.
Acquisition of such a feature could have given the Cervisa yeast a distinct survival advantage compared to the Candida yeast, in the event of a radical change in the composition of the Earth's atmosphere. Exactly, a combination of environmental and genetic changes led - and still leads - the evolution of the living world on Earth for millions of years, up to the situation we know today.
Prof. Barkai is a physicist by training, currently engaged in life science research. Her original research approach recently earned her the Helen and Martin Kimmel Award for Innovative Research, awarded on behalf of the Weizmann Institute of Science and accompanied by a research grant of one million dollars over five years.
16 תגובות
Age –
I think you are confused. The name of the article is 1-0 for evolution. I agree with you about the rest of the order.
seagull -
I think it's cooler to be without molars. Dental infections were a significant cause of death before the invention of sterile dentistry and antibiotics.
At the moment humanity is undergoing evolution, and in developed areas people are starting to be born without the third set of molars... which nowadays are starting to be unnecessary, because our teeth are healthier and stronger than before...
It's not as cool as wings, but it will at least save appointments at the dentist 🙂
I invite everyone to see the article "0-0 for evolution". Regarding who showed that evolution is not possible and who did not.
Mr. Jonathan
Maybe instead of telling us what is not a mutation, you tell us what in your opinion is a mutation, and then maybe the commenter will come and redeem you.
In my humble opinion, all the examples brought to Eyal are mutations. My dog has a dozen teats and she will be very angry if she knows that in your opinion all the above teats do not improve her and her offspring's evolutionary survival ability.
only with a smile
Sabdarmish Yehuda
Sorry! All the examples given above cannot be called real mutations, the appearance of additional nipples, skin color, sickle cell anemia, viruses... This is not evolution, these are random mistakes, or expressions of existing genes. Why not include cancer as "proof" of evolution, a chick with two heads, all the breeds of dogs and cats developed in the last five thousand years and all the freak phenomena around Chernobyl?
I'll admit, when I wrote the talkback I was sure it wouldn't take long for someone serious to explain where I went wrong. The correct talkbacker may not have responded yet. I'm waiting.
Yehuda -
Randomness is important, but so is the ability to find out.
Thanks for the recommendation, and have a good day.
In fact, the response is addressed toRoey Tsezana, Gil apologizes.
age
You are wrong about the randomness, it has an important role in evolution and maybe even a main one.
I highly recommend the book by Professor Yuval Naman - Seder Man Akraai.
Have a good weekend.
Sabdarmish Yehuda
age
See my comments in the comments - 1-0 for evolution.
I bring there two arguments why your statistical calculation is wrong.
In summary:
1. The amount of possible mutations that keep the gene functioning is huge (see an example in my response)
2. The system does not sample the entire state space. Anyone who has worked with genetic algorithms can attest to the speed of convergence to a solution, even when the start and generations are chosen completely randomly
In addition to the lion:
It is known that in some areas plagued by malaria, a mutation has developed that creates sickle cell anemia. This mutation (which is usually considered harmful) has a certain ability to protect against malaria.
Well, you've already gone through all the answers. I have nothing left to answer the original questioner.
Well, maybe a fun little extra after all. Some people are born with an extra nipple or two, located in the upper abdomen area. Definitely a lovable mutation, if there was an environmental pressure causing only the people with 3 nipples or more to survive, we would surely see it develop into something more interesting.
Age –
Your 'proof' is based on the false assumption that evolution is random and not through natural selection. It proves nothing apart from the fact that you like to play with numbers.
We constantly see mutations in creatures that have a short life cycle. There are many examples from viruses, bacteria and arthropods. But humans also have mutations. Yonatan, did you know that until 50 thousand years ago all the people in the world were black-skinned (yes, like today's Africans) and today most people are "white" or other colors. This is a mutation that began and became established in a very short time in evolutionary terms (on the order of ten thousand years), because of the survival advantage of white skin in a relatively cold and sunny climate - from the moment some of our ancestors migrated from Africa to the north.
It should be mentioned that all the time of the universe was not enough to create even just one gene. I showed this in detail in the article called "0-0 for evolution"
In addition to the correct things that Yehuda pointed out, you are talking about evolutionarily short periods of time. The exponential increase in the number of humans occurred in a period of time that is a blink of an eye from the long-term perspective of evolutionary changes. Of course, the genetic variation has increased in the last few centuries also due to technological, transportation, cultural improvements, etc., but from here to growing wings there is still a long way to go...
Good evening to Jonathan
If you believe in creationism then you probably know that there are people with wings who are called angels.
If you don't believe in creationism then you understand that there was no advantage to all the phenomena you said would have come instead of more important features.
The pressure of the environment does not favor us with gills therefore even if someone starts to develop some pre-, pre-gill, it will be lost in the subsequent generations of his descendants.
So the amount of details is not important, but whether the mutation helps Lizner to survive.
Good night
Sabdarmish Yehuda
6.5 billion people live now.
In my opinion, this is the highest number, of the total number of humans and hominids that have ever lived on Earth in the last two million years. Why don't we see real human mutations that are required from a statistical-evolutionary point of view at least? So, for example, why don't we see humans starting to develop wings? Or gills? Or even those with phenomenal sight or hearing? Same for cockroaches?
It seems to me that this simple fact of life contradicts the theory of evolution and what this article purports to assert.