Question

Black hair (B) is dominant to brown hair (b). Cross a black rabbit and a brown hair. The black rabbit had a brown haired mother.

Answer 1

Answer:

Genotypic ratio = 1 Bb: 1 bb

Phenotypic ratio = 1 black rabbit : 1 brown rabbit

Explanation:

This question involves a gene coding for hair color in rabbits. The allele for Black hair (B) is dominant to the allele for brown hair (b).

According to this question, a black rabbit whose mother is brown haired (bb) is crossed with a brown hair rabbit. This means that the black rabbit will have a genotype 'Bb' while the brown rabbit will have a genotype 'bb'. Each parent will produce the following gametes:

Bb - B and b

bb - b and b

Using these gametes in a punnet square (see attached image), the following proportion of offsprings will be produced:

Bb, Bb, bb and bb

This means that the;

Genotypic ratio = 1 Bb: 1 bb

Phenotypic ratio = 1 black rabbit : 1 brown rabbit