In rabbits, the gene for gray hair dominates over the gene for white hair. In a gray rabbit, when crossed

In rabbits, the gene for gray hair dominates over the gene for white hair. In a gray rabbit, when crossed with a white, all offspring were gray. When F1 hybrids were crossed, 31 gray and 9 white rabbits appeared. What is the genotype of the parents and offspring?

Let’s designate the gene that causes the development of gray hair in rabbits as B, then the gene that in the homozygous state leads to the development of white hair will be b.

Since all rabbits in F1 are gray, it should be concluded that both parent rabbits are homozygous. The gray rabbit will be BB, it will produce the same type of germ cells B. The white rabbit will be cv, its germ cells – b.

All the first generation of rabbits with a gray coat will be Bb. These rabbits will produce two types of germ cells, b and B.

The offspring obtained by crossing such rabbits will look like this:

gray homozygote rabbits (BB) – 25%;

gray rabbits – heterozygotes (Bb) – 50%;

rabbits with white hair (bb) – 25%.

The obtained splitting according to the coat color (3: 1) corresponds to the actually obtained results presented in the condition (31 gray to 9 white rabbits).

Answer: parent rabbits – BB and cc; rabbits – BB, Bb and bb.