A three-gene system of additive genes (A, B, and C) controls plan...

Question

A three-gene system of additive genes (A, B, and C) controls plant height. Each gene has two alleles (A and a, B and b, and C and c). There is dominance among the alleles of each gene, with alleles A, B, and C dominant over a, b, and c. Under this scheme, the dominant genotype for a gene contributes 10 cm to height potential, and the recessive genotype contributes 4 cm.

What are the phenotypes and proportions of each phenotype among the F₂?

Accepted Answer

Hey, everyone. Let's take a look at this question together which of the following methods can be applied to expand the Punt square, especially when dealing with more than one gene or more than two alleles for a gene. Is it answer choice. A, the fork line method, answer choice B, the foil method, answer choice C, the line method or answer choice D both answer choices A and B. Let's work this problem out together to try to figure out which of the following methods can be used to expand a puit square. So we know that a puit square is used to predict genotypes in a cross between parents. However, when we are dealing with more than one gene or more than two alleles, for example, we have a cross with one parent that is heterozygous for A and heterozygous for B with another parent that is homozygous dominant for A and homozygous dominant for B. And we want to predict the genotypes of their offspring. However, we know that they have more than one gene. So we use a method where we have that cross between those A alleles and we know that one half of the offspring are homozygous dominant, and one half of the offspring are heterozygous. But next, we have to determine what the predicted outcome would be for the cross of the B gene. And so we use a method that branches off from the A gene giving us those expected outcomes for the B gene. And the method that we use where the crosses branch off is called the fork line method, which is that method that can be used to expand that Punt Square in a case where we have more than one gene or more than two Ailes four gene. So answer choice, a fork line method is the correct answer. I hope you found this video to be helpful. Thank you and goodbye.

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