for-a-test-of-the-neutral-theorys-prediction-that-the-rate-of-evolution-is-equal-to-the-mutation-r-2

Name: for a test of the neutral theorys prediction that the rate of evolution is equal to the mutation r 2
Uploaded: 2020-06-30
Duration: 3 min 4 s
Channel: Numerade
Description: For a test of the neutral theory's prediction that the rate of evolution is equal to the mutation rate, see:

Question

For a test of the neutral theory's prediction that the rate of evolution is equal to the mutation rate, see:

Camilla Martin · Accepted Answer

the major difference between the neutral mutation hypothesis and balancing selection. The neutral theory, also known as neutral mutation hypothesis, um, holds that most genetic variation is due to the accumulation, uh, neutral. Excuse me? Neutral mutations via random events, right? Like genetic drift? No. Put that off to the side. Right. So it&#x27;s effectively neutral. Memphis variation is neutral. How can it affect fitness? Right. Um, the balancing selection, you&#x27;re balancing hypothesis here to go and put balancing hypothesis proposes. That&#x27;s genetic variation is actually maintained by selectively favoring hetero szaggars. So that way we get organisms that you know are on both ends of the strict spectrum also, and along that median, right? So the major difference is definitely focusing on my item of genetic variation being either neutral right, which actually would had have no effect on fitness and then balancing is referencing the ability to maintain variation by favoring Hatteras I goats and actually really interesting example of that. Of course, it would be sickle cell anemia patients, right? Those who are headers, I guess, actually have an increased or higher fitness due to protections against malaria. Right? But the homo zygotes would have decreased fitness they&#x27;re not protected against malaria, whether they have sickle cell anemia or they don&#x27;t have sickle cell anemia. But this keeps both extremes still present, which allows for that genetic diversity. So this is a major difference between neutral, um, mutation of offices and balancing selection.

Kendrick Buford · Answer

All right. So we&#x27;re thinking about the interplay of natural selection and Jeanette Drew and we talked about natural age if you don&#x27;t chapter. But I want you guys to know that you need drooped is just basically the variation of our of the frequency of a deal. Type in a small population oh, into the chance of a particular gene disappearing because individual die. So basically, you have a small population and you don&#x27;t pass on your genes. You have greater die out of jeans because, I mean, you know where to get their gene from you die out and your population is too small, you don&#x27;t actually have as much of a chance to share. So Michael Lynch had our pots. Is that mutation rates are determined by interplay between natural selection and genetic groups. So both needs to get played their part. So what kind of experiment could you have to which will be designed? Have you keep me different types of E. Coli each of different effective population sizes? 1000 generations using that type of experiment? How Lynch&#x27;s hypothesis predict that mutation rates will evolve, so you just have different sizes of E. Coli small colony enable small a tiny bit colony Hughes, Kaufman and banks. So you just let these colonies do what they do and reproduce 2000 generations. So let&#x27;s hypothesis is correct if you have a large population sides So this guy right here, he would have lower of mutation, res and small loans. Who? This guy right here. We have higher population mutation rates and this is because the small populations are affected. Maura Maginn. It droops. So it&#x27;s not quite a mutation itself, Janet Group. But Jeanette Drip does help expedite the elimination and change of the total genetics of a population.

Courtney Burson · Answer

So this question is not really question, but it&#x27;s having us look at the literature for an example of convergent evolution. And so the paper that they provide is called molecular functional basis off, you know, typical versions on white lizards. And so there was three species of lizards of the pounds glare, a plus on the lattice aspecto Selous in, or Nada and Hope Rocchi Immaculata, who have present a white FINA type on these dunes that are really white. And then there is also, like a darker, you know, type that lives like in a more of a brown desert e area. And they Iran, um, a few different types of ties, some like delay, jobs and essays and whatnot. And they found that all these three lizards, they&#x27;re different species and everything. They have mutations in the same gene, but the results in different mechanisms. So the mutations in the M. C. R one gene, which is important if pigmentation across a wide variety of species, including humans and there was two different mechanisms. So there was one. The receptor singling got mutated and then to the receptor to the emcee are one, um, had difficulties integrating in the membrane and from the amino acid was different. I got mutate was different in each of these three species, so it&#x27;s the same gene. There&#x27;s two mechanisms. So too had one way one had one way, but then the three, the each one had to for an amino acid that and mutated.

Sarah Mccrumb · Answer

everybody. So the face theory of evolution, the one means that evolution is D. It&#x27;s tested and cool Averies.

April Townson · Answer

for this question were being asked to do two things. Number one is to know the definitions of synonymous and non synonymous substitution and to to be able to apply that to the different types of selection, namely positive, neutral and purifying selection pressures. Now, right off the bat, we can go ahead and remove Option D from our possible choices. And the reason for that is concerted. Evolution is a term used to describe what happens when a group of genes that are closely related those in gene families, for instance, that might arise due to gene duplication evolve together due to their similarities. And usually they&#x27;re close locations on the same chromosome. This option describes multiple dreams at once, which is very different from the other options here, and it is also capable of in capturing the different types of substitutions and the different types of selection pressures. So it&#x27;s not any it doesn&#x27;t fit into these categories, but it can use them. And so because it isn&#x27;t really related to what we&#x27;re looking at for this question, we can go ahead and remove it. So now that we&#x27;ve narrowed down our answers just a little bit, um let&#x27;s start out with defining synonymous and non synonymous substitution. The whole concept is based on two big ideas. The first is that errors and DNA replication and indeed a crypt. Stranz transcription Excuse me, will happen. These air not error proof things. And occasionally you will have a case where a substitution in a nucleotide is made. And what happens here is you might have a seat suddenly turn into a G or in a become a T or you are. It depends obviously on it for dealing with Deanna or in a But that&#x27;s what a substitution is now. The second major thing to remember here is that many code ons, those three nuclear tied bases that when I read together and code for specific amino acids, these can actually code for the same amino acid, even if they are read differently in terms of their bases. So in this instance of G. U C and G u A R. Two different code ons that both encode the same amino acid. So these air the to sort of overarching of concepts that are behind the scenes in these two terms. Um, now, when this type of substitution happens, we get what is called synonymous Substitution. This means that there is no change in the resulting amino acid. Another term for this is silent substitution. And a good way to remember this is that the coat on or the basis here are like a synonym of each other for the same amino acid, just like synonyms for words, different spellings of different combinations of letters. Me for that together can form different words that mean the same thing. And if you were to read out all of the different bases, they might in two different, uh, genomes. That one has made a synonymous substitution, and one hasn&#x27;t, uh, they might read differently in terms of their faces, but if you read the resulting amino acid chain, they would be the same. So they&#x27;re synonymous. What happens in the other case? Because again, this isn&#x27;t possible. All of the time is that you would get a non synonymous substitution, in which case there would be a change in the amino acid base. Um, for instance, in this case, changing one base and going from a G to a G C. Let&#x27;s say this was an error in transcription or something in that field. Um, you go from encoding bargaining to including ceremony Syrian. Excuse me, and sometimes you could actually encode a stop coat on, in which case you would end the amino acid chain prematurely and whether or not you&#x27;re ending it or you&#x27;re adding in or substituting a different amino acid. This can have dramatic effects on the resulting protein, and thus depending on what that protein is being used for effects on the organism or the tissue or as a whole. Um, so now that we have these definitions down, let&#x27;s move on to the other part of the question, which is understanding the different types of selection pressures. There are generally three main paths, and in this context, these selection pressures define situations where an amino acid section like a coat on or a particular base his under pressure to mutate or not. Uh, whether or not it&#x27;s beneficial for the organism to continue tohave that base or not. Basically the first possibility is neutral selection pressure, in which case there is no preference either way for a mutation or not. Um, so this you you will probably see mutations because, like I said, earlier errors will happen. But there won&#x27;t really be any preference for whether those errors stick around or how frequently they happen, whether they&#x27;ll fixated or not. And it becomes left up to genetic drift. A lot of the times there that&#x27;s one of the options in this case. Another route that can happen is when an amino acid position is under positive selection pressure. In this case, changing the genetic code or in the amino acid chain is a beneficial thing. Maybe it&#x27;s a situation where more genetic variety is needed. Maybe this the protein that&#x27;s being encoded could be improved upon in this environment that the organism is living in the or the species of it. Um, what? The ultimate thing is that under this type of selection, pressure mutations are a good thing, and they&#x27;re sort of evolutionarily desired. Um, finally, an amino acid position contender grow purifying, or sometimes they used to be called negative selection pressure. In this case, this position is under pressure to not change to stay the same. It&#x27;s trying to avoid dangerous mutations, in other words, trying to purify the population of military ISS mutations or traits. This might be a case where um this gene or amino acid changes associated with a very specific thing like development or something necessary for the organism to survive in its environment. And you wouldn&#x27;t want to get rid of that or to change that in case it leads to the offspring&#x27;s, um, lack of fitness. And so now that we&#x27;ve gotten all of these definitions laid out, let&#x27;s return to our question and figure out which one of these different paths you would expect with synonymous substitution. Or would you expect to see that as the most common type of substitution? So let&#x27;s start out with neutral evolution, since there is no pressure either way for the amino acid chain to stay the same or to change itself. Given the laws of chance and variation, you would probably expect to see roughly equal amounts of non synonymous and synonymous. Substitution is happening in this pathway. Um, as so both are equally probable in the case of positive selection. Remember, there&#x27;s a pressure for this amino acid to change into something different. In order for it to change, we need a non synonymous substitution. So in the case of positive selection, we would be looking for none soon on of us substitution in the case. Finally, of purifying selection, however, there is pressure to not mutate this amino acid change or the gene product in order to avoid dangerous mutations. In this case, we would expect a stronger selection pressure towards keeping the amino acid change the same. As I said earlier, however, errors in the transcription and the replication process can happen, so you will still see substitution. But there would be a stronger pressure for these to be synonymous. So they keep the same amino acid. Uh, shame. Therefore, our answer in the end, is a

Problem 25 Easy Difficulty

For a test of the neutral theory's prediction that the rate of evolution is equal to the mutation rate, see:

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