The findings published yesterday (Thursday) in the journal Nature reveal an in-depth genomic analysis that encodes how the E. coli bacterium adapts itself to be added to the traditional glucose diet to which a decent dose of citrate has been added.
A team of researchers from Michigan State University has documented step by step the process by which creatures develop new traits.
The findings published yesterday (Thursday) in the journal Nature reveal an in-depth genomic analysis that encodes how the E. coli bacterium adapts itself to be added to the traditional glucose diet to which a decent dose of citrate has been added.
"It's cool to see how a new biological trait evolves," says Zachary Blount, a postdoctoral fellow at Michigan State University's Bacon Center for the Study of Evolution in Action. "The first bacteria that ate citrate barely managed to grow on citrate but they improved over time. We wanted to understand the changes that allowed the bacterium to develop new abilities. We were lucky to have a system that allowed us to do that."
Normal E. coli bacteria cannot digest citrate in the presence of oxygen. In fact, it is an identifying mark of a sonic island. They cannot digest citrate because E. coli cannot express the correct protein needed to digest the citrate molecules.
Blount together with Richard Lansky, professor of microbiology and molecular genetics at Michigan. A long-term experiment that Lansky began in 1988, in which he grew cultures of fast-growing E. coli bacteria, will allow him and his team members to study more than 56 generations of bacterial evolution.
The experiment showed natural selection in action. Because the samples of the bacteria were frozen and available for later study, when something new emerged, the scientists could go back to previous generations and examine the steps that occurred along the way.
"We first saw the bacteria that use citrate around the 33rd generation" explained Lansky. "But Zeke was able to show that some of the important mutations had already occurred before. Then, watch a replay of the evolution at various intermediate stages. He showed that re-evolution could be induced in the citrate eaters, but only after several other pieces of the puzzle had been put in place."
In the paper, Blount and his team members analyzed 29 genomes from different generations to find the mutational pieces of the puzzle. They uncovered a three-step process by which the bacterium develops new abilities.
The first step was potentiation, when the island. Cooley acquired at least two mutations that set the stage for later events. The second layer actualization occurs when the bacterium first begins to eat citrate but only barely bites into it. The last step, refinement, involves mutations that have already improved the initial weak feature. This allowed the citrate eaters to attack the new food source and become dominant in the population.
"We were especially excited by the actualization phase," Blount said. "The mutation involved in this is quite complex. It rearranges parts of the bacterium's DNA, and builds a new regulatory phase that did not exist before. This new component causes the production of a protein that allows the bacterium to introduce citrate into the cell in the presence of oxygen. It's a new trick for Ei. vocal." This is a far from normal change." Lansky said.
"This was not a typical mutation at all, when only one base pair, or one letter in the genome changes." said. "Instead, part of the genome was copied so that two blocks of DNA were joined together in a new way. One block encoded a protein that made it possible to get the citrate into the cell while the other caused the expression of the protein."
Researchers from the University of Texas and the University of Calgary also participated in the study.
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true
There are quite a few cases where new species have been created. There is no doubt that evolution works and it is easy to understand why.
What the experiment gives is the study of the different complements. It is also an excellent learning tool because the researchers keep track of all the steps along the way.
The title is quite misleading. It is true that a creature after a mutation is not the same creature, but to call it a new creature is sensational but also trending consciously or unconsciously. This promotes, for those who are not aware of the details, the idea of the origin of species in which an inferior creature gives rise to a more complex creature. In the end it is a creature with the same number of genes except that in some of them the code has changed and it is not a creature of a new breed and certainly not more complex.
There are cases where mutations occur that do not help survival, such as polydidacty (3 fingers), but of course a mutation that manifests itself is not such a common case. Blue eyes are also the result of a mutation. The question is whether the mutation is likely enough to happen, if it was likely that the genetic order would be changed randomly as a result of a disruption or error in the copying of the information so that the structure of the nose would change or the shoulder in such a way that there is an additional finger or nostril, then it would be reasonable to assume that they would be applied from time to time on the assumption that they do not harm the survival of the individual. Of course, it is important to know whether that new gene is dominant or recessive, and it is also important to remember that initially mutations of antibiotic resistance in bacteria or relatively high neck elongation in giraffes were rare and only due to natural selection became common.
If randomness is indeed the cause of those changes, we should see hundreds and thousands of strange phenomena and sights in the living world, not only as a result of a damaged gene, for example a finger growing in the shoulder or a nose with three nostrils and many more such.
These are features that do not interfere with survival and therefore they should have appeared today if indeed everything is random over millions of years.
When I saw the cancer where it was claimed that the eye is so complex and precise is a product of randomness, it seemed even ridiculous to me.
It is claimed that a feature suitable for the environment will survive, meaning that there is a close connection between the environmental conditions and the feature, in my opinion the environmental conditions also affect the formation of the feature. And not only for her survival.
An addition to Kobi's words. Evolution does not see the unborn. If we assume that 100 mutations are required for the development of a new feature (for example: one estimate is that a minimal protein requires a third of its length for minimal function), the sequence space is 100^20. Natural selection cannot sort out such a complex trait. So how do we find such complex features in nature?
We cannot define
Maybe once we open up and advance and the technology and computing as well, we can finally discover and understand, that we will never be able to understand
We can define what the laws of nature and the laws of the universe really are.
There are indeed "intelligent" signs even in random changes of the mutations to the "understanding" observer
But it is very difficult to characterize them on a human rational level.
It just happens.
And maybe the whole discussion is purely philosophical..
legal,
The friendly function of the bacterium was just an example. I argued that the basic pattern is preserved despite the random mutations. If the mutations were truly random we should see changes in the pattern as well, and not just slow changes that maintain a pattern, except in a case that requires a solution.
By the way, the fossil findings also do not show pattern changes. We see development in the form of a "jump" between stages. And from the moment we find the animal the changes are really minor compared to today. Which proves my point that DNA maintains a template, until for some reason it has to make a jump. Relatively small in the case of a bacterium, and huge in the case of a large animal.
I said that you don't see "only" random changes. Of course there are random changes. The question is what comes out of them. I say that there are mutations all the time that in most or all cases keep the original pattern. Except for a situation where the organism has to solve a problem, then changes of a different kind occur. As in this case, where there were thirty thousand generations that seemed to lead nowhere, nor did they have survival value, which is a legal season. Until the new function was created there was no natural selection, because at the beginning of the changes there was no higher survival value. It seems as if the bacterium "knew" that at the end of the process there would be a solution, therefore the process was directed. If there were only random changes without striving for a solution, the chance of survival would tend to zero. The number of random combinations in a bacterium is enormous. Something like ten to the power of 400. If there is a process of selection in every change it only reduces the low probability, but here we witness changes as if they were random over thirty thousand generations until there was some survival advantage. It points to a mystery we find in many cases. And the researchers mostly tend to ignore it.
someone
Kobi certainly emphasized what I argued in a convincing way.
I do not claim a higher power, I only claim that it has not been proven that the changes are random.
Regarding the experiment I proposed, if in group A there are changes in details identical to those in the details in group B, when the two groups are completely separate from each other, this shows that the changes are not random.
Hope it's clearer now,
In my opinion, the changes are slow, and it is not certain that they will bring change, you have to take that into account..
Kobi,
A. You stated that you do not see any irrelevant changes and you are not right in this
B. You wrote that harmful changes disappear and are not passed on to future generations.
The changes generated are completely random and never goal oriented. What appears to be "goal-oriented" is the natural selection that constantly operates on organisms and chooses among them those fit for survival at the expense of those less fit. This is because the amount of resources available to a population of organisms is limited.
Bacteria do not become good for us because it is bad for them.
Another amazing thing, we see that the normal mutations hardly change the organism. For example, we do not see the addition of a seemingly irrelevant function in a person or an animal. And in cases where it does it only causes cancer and immediately disappears. And here we see a feature that develops over more than thirty thousand generations! Even if an irrelevant feature can remain, as claimed. We were supposed to see endless random changes over thousands of generations. which would necessarily have completely changed the pattern of the organism. And with almost absolute certainty he was the cause of his destruction. something we don't see. For example, a harmful bacteria, only a developer can overcome the antibiotics. which is an obstacle he encountered. And we never see that it suddenly lost its harmful feature in favor of some friendly function that developed over thousands of generations.
There is no one to answer him. The argument is simple. We do not see only random changes that occur at a slow rate and do not cause a fundamental change in the organism. Rather, it is a case where the DNA encounters a problem it must solve, and then we see goal-directed changes. As if the organism "knows" that it must solve some problem later. The problem is that he cannot "know" but nevertheless has some kind of built-in feature that allows dealing with such problems. Which raises serious questions. Something that evolutionists tend to overlook is that most changes are goal-directed. Such as in the case that a bacterium is required to deal with a new situation. The bacterium itself produces many mutations with natural selection. And then, as if by itself, a solution was "created".
The fact, that what was observed all the time is only the addition of relevant functions. And not a change from gender to gender. There is no denying that a species can and must adapt to its environment. Of course, you can use the mechanism to select dogs of different breeds. But don't turn a species into another species. The organism still maintains a basic pattern.
I saw an interesting article in the National Geographic about the hybridization of many species that have been selected such as dogs and birds. But when we gave them a few generations to mate freely they reverted to their basic pattern.
someone,
I do not come to contradict your words (I completely agree with them) but only in one small detail: it is not necessary that each of the tiny changes will bring any benefit, it just needs to not cause harm. Many changes can occur and accumulate without bringing any benefit except at the moment when the conditions change. As a matter of fact, if when the conditions change there are no changes in the genetic pool that can be useful, the survival chances of the said population are extremely low.
The truth is, the experiment you proposed is not entirely clear to me and I did not understand why it proves what you claim it proves, maybe you would like to explain again.
As you know, many experiments were conducted with bacteria that showed how they undergo mutations, change and adapt themselves to a new living environment. How are these experiments different from what you proposed?
Many computer simulations also show that the evolutionary mechanism works, in fact there is a very wide field of evolutionary programs that manage to reach very optimal solutions for problems that cannot be solved in any other way.
In my opinion, the videos are very convincing, they show beautifully how a feature that seems very complex to you can actually be created gradually step by step, through many small changes, each of which in itself brings some benefit to the animal, and therefore it survives.
The explanation you allude to regarding a "higher power" that supposedly directs things consciously sounds much less logical because then you have to explain how that higher power came about and then you're back to square one. The many flaws in our bodies also, in my opinion, completely rule out the possibility that someone intelligent created us.
Also see agricultural crops such as bananas and corn that we developed through evolutionary processes only of artificial selection (which is exactly the same process that occurs in nature) they are not at all similar to the wild banana or untamed corn. That is, with the help of a repeated process of selecting the plants with the best properties and breeding them, they created completely new varieties of plants that do not exist in nature, the same goes for many dog breeds that we created exclusively through a process of artificial evolution.
That is, you have here conclusive proof that cannot be argued with that the evolution process works and that an animal or a plant can change drastically without any intervention of genetic engineering.
There is a nice experiment with foxes conducted in Russia, if you don't know I will send a link.
someone
Thanks for the articles, it didn't really change my mind, but you can do a simple experiment to determine what is true,
A few groups of bacteria of a certain type are isolated and the food or temperature is changed during several tens of generations.
If it turns out that the change that took place in the details of the different groups for the purpose of survival is the same, this will negate the notion that the change is random. And if there is randomness, we will find different "solutions" for survival among the individuals in the groups.
Seriously, my response has been released, I suggest that as a start you watch the three short videos I linked to, to activate Hebrew translation subtitles in the first video, click the "CC" button below the video.
The two additional videos already include a built-in translation into Hebrew.
As you will see, features that seem very complex to you can be formed over time from the accumulation of small and random changes, each of which brought some benefit to the animal, therefore they survived and were passed on to the offspring until they finally formed together into the complex feature that you see today.
Father, why is my response delayed for so long?
The claim that the series of changes in the bacterium was random is accepted, but is not proven - or if someone knows a proof, tell me about it. Since we know that chemicals, radiation, and more, cause changes, citrate is also a chemical, why eliminate the possibility that caused the changes?
I hope my response will be released soon, in the first video I gave, click on the subtitles icon (below the video) to get Hebrew translation subtitles.
Previously, "CC" appeared on the icon, but I think they changed it to something else.
The other two videos already include Hebrew translation subtitles Build In.
Seriously, I started to write you a detailed answer on the subject, but I see that it is already starting to take too much time from me, which unfortunately I don't have at the moment, so I stopped. I will try if I have time to come back here and answer you, because there are definitely excellent answers to all your questions.
In the meantime, here are three short videos that I think will answer most of your questions:
http://www.youtube.com/watch?v=Hk0JbHyApQw
http://www.youtube.com/watch?v=7ZZ7WogHxaY
http://www.youtube.com/watch?v=AWBOYhYGmOk
What is important for you to understand is that a feature does not develop all at once randomly, but is built from many small steps/changes each of which either has a benefit in itself, or slightly improves an existing feature.
Ernest,
First, we see many strange phenomena in the world that result from harmless genetic changes that are passed from generation to generation until they become harmful (in changing conditions) and cause the extinction of those who carry them or they are beneficial and then spread in the population that carries them.
Second, the appearance of mutations is completely random. What is not random is the filtering of the harmful mutations out of the population. Note that harm can also be the rejection of the mutation carrier by other members of the population, a fact that may cause him not to pass on the genes with the mutations to future generations.
to ernest
There is no "goal" and certainly no "planning",
Each change is completely random and its cause will survive only when
The environment and conditions enable its survival,
Even if the change is not positive for the animal there is a possibility that it will survive,
See all the defective genes that cause diseases.
someone
In the above case and in other cases where a trait or ability develops over a very long period of time, it is hard for me to accept that it is random, even though this is the way most researchers think.
Since neutral random change is supposed to survive like the "beneficial" one, we should see endless strange phenomena in the natural world that survive for millions of years, but this is not the case, so I think there is a sophisticated mechanism that causes the changes
Purposeful, designed, in order to survive in a changing environment.
Seriously, the changes themselves are indeed random, but if they bring the animal any benefit, or even if they are just neutral and do not cause any harm, then they will remain and be passed on to future generations, as explained in the article, some changes of this type crystallized at some point into a more complex feature that brought the animal Benefit in the living environment in which it is found.
The changes are indeed random, but the living environment filters and passes on only those of them that bring benefit, this is natural selection.
my father
Is it correct to say, according to this article, that it is a gradual development of a trait or ability?
Between the many generations, towards a certain goal or destination, and not random changes, created the same feature.
This is not exactly new and the results of the experiment have been known for a long time. Actually it is a change in regulation and maybe even genetic destruction. Here is a review article regarding this experiment (and many others) published in the scientific journal The Quarterly Review of Biology:
http://www.jstor.org/discover/10.1086/656902?uid=3738240&uid=2&uid=4&sid=21101066842543
In addition, it is only a few mutations, so it is not clear what the fuss is about. There is no new complex system here. The bacterium already had the ability to digest citrate before. As mentioned, the innovation is only in the entry of the citrate into the cell in the presence of oxygen.
It was more interesting to see the development of citrate digestion than nothing. It really could have been impressive, assuming that it required a whole protein.
Come on, isn't it clear to you that now the on-duty creationist will come and say that this is just another example of microevolution, but that doesn't prove macroevolution?
Kudos to the Michigan State University researchers!!!!
Rapid evolution in 14 years.