A black guinea pig crossed with an albino guinea pig produced 12 black offspring.When the albino was crossed with a second black animal,6 blacks and 6 albinos were obtained.What is the best explanation for this genetic situation?

Question

Quizplus · Accepted Answer

The fact that the black guinea pig crossed with the albino guinea pig produced all black offspring suggests that black is dominant and albino is recessive. In the second cross, when the albino was crossed with a second black animal, 6 blacks and 6 albinos were obtained, indicating that the black animal in this cross was heterozygous (Bb). The cross can be represented as follows:

Bb (black) x aa (albino) = B_ (black offspring)

B_ (heterozygous black) x aa (albino) = 1 BB (black), 2 Bb (black), 1 bb (albino)

This is consistent with the inheritance pattern of a dominant/recessive trait.

A Black Guinea Pig Crossed with an Albino Guinea Pig