What factors cause quantitative variation in a trait within a population?

Video transcript

Hi all here's our next question which of the following does not affect a little frequencies in a population. So we're looking for the answer choice that will not have an effect on the frequencies of gene alleles in a specific population. So let's walk our way through these choice A says non random mating. Well non random mating would mean that there's a mating preference for a certain trait or traits that is going to affect the allele frequencies. Because the allele responsible, we'll start becoming more frequent in the population because more individuals without a legal will reproduce successfully. So choice A non random mating is not our answer choice. B says migration. Well migration will affect a low frequencies because depending on which individuals migrate out of the population. Or if if you look at the allele frequencies in the new populations migrated somewhere else, they may not have divided evenly. The animals won't necessarily sort themselves out. Or the individuals. So if you have um more individuals with one alley than the other leaving the population uh You so if you have um and a leo migrating in greater numbers or I should say individuals with that alley. The frequency of that A little will go down in the original population. So that's not our answer choice E says absence of natural selection. Well this hopefully kind of rings a bell in our mind because we recall from our content videos that when you talk about a low frequency, you're almost always talking about the hardy Weinberg equilibrium. And that says in the absence of natural selection, the frequency of alleles in a population remain constant. So right there we see that in the absence of natural selection, since our allies remain constant, our allele frequencies will not be affected remains constant. And that's because you don't have natural selection favoring the reproductive success of individuals with one over the other. So our correct answer. Choice. C absence of natural selection. Um We'll just take a look quickly at choice. Their last remaining choice choice D. Choice D. Says genetic mutations. Well that is also not the correct choice because that will introduce new alleles into the population when we have mutation. So obviously that will affect all your frequencies. So choice D. Not our answer. So again, which the following does not affect a low frequencies. That is the absence of natural selection. As we recall in our hardy Weinberg equilibrium. Hope that helped see you in the next video