In chickens, the pea crest gene dominates over the simple crest gene, and incomplete dominance is observed

In chickens, the pea crest gene dominates over the simple crest gene, and incomplete dominance is observed for black and white genes; heterozygotes are blue in color. If you cross birds that are heterozygous for both genome pairs, then what proportion of the offspring will have a pea-shaped crest and blue color?

Let us designate the gene that determines the development of the ridge in pea-shaped chickens as B, then the gene for the simple ridge will be b.

Let’s designate the gene that causes the black plumage of chickens as C, then the gene for white plumage will be c, and chickens with blue plumage will be written as Cc.

Hens and roosters heterozygous for both genes will have BBC, which corresponds to a pea comb and blue plumage. Such individuals will produce sex cells BC, bc, bC and bC.

All possible offspring from crossing such roosters and chickens among themselves will be represented by the following options:

black chickens with a pea-shaped crest (2ВbСС, ВВСС);

blue chickens with a pea-shaped crest (2ВВСс, 4ВbСс);

blue chickens with a simple comb (2bbСс);

black chickens with a simple comb (bbcc);

white chickens with a simple comb (bbcc);

white chickens with a pea-shaped crest (2Bbcc, bbCC).

Blue chickens with a pea-shaped crest – 6 genotypes out of 16, or 3/8., Or 37.5% of all chickens.