A pea plant that has the genotype RrGgwwdd is crossed to...

Question

A pea plant that has the genotype RrGgwwdd is crossed to a plant that has the rrGgWwDd genotype. The R gene controls round versus wrinkled seed, the G gene controls yellow versus green seed, the W gene controls purple versus white flower, and the D gene controls tall versus short plants. Determine the following;

What proportion of the progeny are expected to be round, yellow, purple, and tall?

Accepted Answer

Welcome back. Let's look at our next question. It says the S gene controls smooth versus wrinkled seed. The R gene controls red versus white seed. The W gene controls white versus purple flower and the D gene controls short versus tall plants. What proportion of the progeny are expected to be smooth, red, white and short. If a pea plant with a genotype, big s little less little R, little R big, W little W little D, little D is crossed with a plant with a little s little s big, R, little, R, little W little W big D little D genotype. When we look at our answer choices, it's important to note that the question is not asking us for the progeny that have all four of these traits at once. So it's not saying how many the project will be smooth, red, white and short, but looking at each of these traits individually, what percent of the progeny will have each of these traits. So for instance, choice a says 50% smooth, 50% red, 50% white and 50% short. This is important because that means we can consider each trait, look at the cross individually rather than have to do some giant punnett square with four traits by four traits. So we looked at choice A choice B says 100% smooth, 100% read 100% white and 100% short. Choice C says 0% smooth, 0% red, 0% white and 0% short. And then choice D is none of these. So there is that chance that none of those answers are correct. So again, since each percentages listed individually, we can look at one trait at a time. So as we look at the s straight, our crosses, big s little s crossed with a little less, little less. Well, that's a test cross of heterocyclic homesickness, recessive and that's going to end up with 50% smooth And 50% wrinkled. Now, let's move on to the R gene where we have little R, little R crossed with big R little R again, same thing. Homesick is recessive, crossed with hetero. So again, we're going to get a 50 50 result. We'll go to the W trait and we have big W little W crossed with little W little W, same result, 50 50. And then finally, the D gene, little D, little D crossed with big D little D also 50. So in each case, we've got a hetero psychosis, a parent that's heroes, I guess for one treat and the other parents home is recessive. So in each case, each trait is represented in 50% of the offspring. So that's gonna be our choice. A here 50% smooth, 50% red, 50% white and 50% short. See you in the next video.

Key Concepts

Genotype and Phenotype

Punnett Square

Independent Assortment

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