In parrots, the sex-linked gene “B” determines the green color of the plumage, “b” – brown.

In parrots, the sex-linked gene “B” determines the green color of the plumage, “b” – brown. The green male is crossed with the brown female. What are the phenotypes and genotypes of F1 and F2?

Based on the problem statement, gene B is dominant, and gene b is recessive. Thus, we can immediately conclude that the female is homozygous for the recessive trait – bb, and the male is homozygous for the dominant trait – BB. When crossed, the entire generation will be heterozygous – Bb – and have green plumage.

P ♀️ bb × ♂️ BB

G b B

F1 Bb all with green plumage

Now let’s consider what the genotype and phenotype will be when crossing two individuals from F1:

P ♀️ Bb × ♂️ Bb

F2 BB Bb bb

1: 2: 1

We conclude that F2 parrots will have the following characteristics: 1 part will be homozygous for the dominant trait and will have green plumage, 2 parts will be heterozygous, also with green plumage and 1 part will be homozygous for the recessive trait and will have brown plumage.