A rooster with a particular comb morphology called walnut was crossed to a hen with a type of comb morphology known as single. The F1 progeny all had walnut combs. When F1 males and females were crossed to each other, 93 walnut and 11 single combs were seen among the F2 progeny, but there were also 29 birds with a new kind of comb called rose and 32 birds with another new comb type called pea.
a) Explain how comb morphology is inherited.
b) What progeny would result from crossing a homozygous rose-combed hen with a homozygous pea-combed rooster? What phenotypes and ratios would be seen in the F2 progeny?
c) A particular walnut rooster was crossed to a pea hen, and the progeny consisted of 12 walnut, 11 pea, 3 rose, and 4 single chickens. What are the likely genotypes of the parents?