The wild-type allele of a gene has an A–T base pair at a...

Question

The wild-type allele of a gene has an A–T base pair at a particular location in its sequence, and a mutant allele of the same gene has a G–C base pair at the same location. Otherwise, the sequences of the two alleles are identical. Does this information tell you anything about the dominance relationship of the alleles? Explain why or why not.

Accepted Answer

Hello, everyone and welcome to today's video. So if we cross a flower with a heteros for T heteros for Y and homo Zygo dominant for W genotype to another flower with a homozygosis for T homozygosis dominant for Y and he for W genotype, what is the chance of producing hetero Saga offspring for all three traits? As answer choice A we have 1/8 as answer choice B we have 1/4 as answer choice C we have 3/4 and as answer choice D we have one half. Well, in order to solve this problem, we need to calculate the individual probabilities of each cross to yield this Saga offspring. So keep that in mind as we solve the problem. First of all, we're going to be introducing two by two punnet squares that we're going to be using to solve the problem as it is present. Now on the screen, first of all, we're going to be starting by the genotype of tea, which for the first flower is going to be heteros. So we're gonna put that on top and for the second flower is going to be homozygosis and then we're going to perform this cross to obtain the following. As we can see, two of 4 or 1/ of the offspring are going to be hetero as it is highlighted. Now on the screen, now, let's move on to why. So the first flower is going to be heteros four gene Y, we're going to be putting that on top and the second flower is going to be homozygosis. We are going to be putting that on the side. Now, if we perform this cross, we will obtain the following. Now, according to this Poet Square, there is also a 2/4 or one half probability of obtaining heterozygous offspring. And we're going to be highlighting them on the punt square. Now, let's move on to w we have homozygous dominant for W on the first organism and we're going to be putting that on top and then we have heterozygous for w in the second organism and we're going to be putting that on the bottom that's performed this cross. Now, now, as we can see, there is also a 2/4 or one half probability of obtaining these heterozygous genotype four W and we're going to be highlighting them on the opponent square. So the probabilities were one half, one half and one half for all three traits. If we multiply these probabilities, we're going to obtain an overall probability of obtaining fully heterozygote of 1/8. And so our correct answer choice here is going to be a 18. I really hope this video helped you and I hope to see you on the next one.

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