Question

A black mouse mates with a brown mouse, and all the offsprings are black.
(a) Why are no brown offsprings produced?
(b) If two of the black offsprings mate with each other what kind of offspring would you           expect  and in what proportions? Give reason for your answer.

 

Answer 1

No brown offsprings are produced because brown colour is recessive, while black is dominant. The recessive trait does not occur in F₁ generation.
(b) We would expect black and brown offsprings in the ratio 3:1. It is because brown colour reappears in F₂generation.