Question

A breeder crossed two chickens, one is a true-breeding black chicken and the other is a true-breeding yellow chicken. All the resulting F1 chicks are black. Several of these F1 black chicks are crossed with the following results: 43 black, 14 brown, and 19 yellow chicks. What kind of inheritance is this? Friend #1 tells you that the answer is incomplete dominance but Friend #2 tells you that the answer is epistasis. You analyze the problem and realize that neither is right. The problem is a trick problem and there is no answer to it.

Answer 1

Answer:

You analyze the problem and realize that neither is right

Explanation:

All intersections and proportions are attached.

First, let's analyze the crossover that formed the F1 generation. At this crossing, chickens of genuine color were used, which indicates that one of them was h0m0zygous recessive (aa) and h0m0zygous dominant (AA). Thus, the entire offspring would be heterozygous (Aa) and would have the color determined by the dominant gene. In this case, all the offspring are black in color, which indicates that in the parents, the black hen is h0m0zygous dominant (AA), while the white hen is h0m0zygous recessive (aa).

In the cross that generated F2, we can see that within the offspring, the individuals in greater proportion are those who present heterozygosity and therefore have the "Aa" alleles. When incomplete dominance occurs, individuals in F2 who have heterozygosity have an intermediate phenotype between the two h0m0zygous phenotypes. As we can see in the question, in F2, heterozygous union members do not have an intermediate phenotype, but the black placement phenotype, which indicates that this is not a case of incomplete dominance.

This is also not a case of epistasis. This is because epistasis causes a gene to eliminate the expression of another gene, whether on the same chromosome or not. The result of this type of inheritance would be that some chickens had colored coloring, while others had no color at all in F2. As we can see, all chickens have colored coloring.

This indicates that neither student is correct.