A pink-crested rooster is crossed with two chicken, also having a pink crest. The first gave 14 chickens, all with a pink-like crest
A pink-crested rooster is crossed with two chicken, also having a pink crest. The first gave 14 chickens, all with a pink-like crest, and the second – 9 chickens, 7 of them with a pink-shaped and 2 with a leaf-shaped comb. The shape of the crest is a monogenic autosomal trait. What are the genotypes of all three parents?
Before determining the genotypes of parents, it is necessary to determine the nature of the inheritance of the crest shape in hens. When a rooster was crossed with a second chicken, 2 chickens with a leaf-like comb appeared. This is possible with the heterozygosity of the parents, therefore, it can be assumed that the pink-like crest in hens dominates the leaf-shaped. Thus, the genotypes of the rooster and the second chicken are Aa.
When crossing the same rooster with the first chicken, no splitting was observed, therefore, the first chicken was homozygous – AA.
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