A yellow guinea pig, when crossed with a white one, always gives cream offspring. Crossbreeding of cream pigs with each

A yellow guinea pig, when crossed with a white one, always gives cream offspring. Crossbreeding of cream pigs with each other always gives a split of 1 yellow, 2 cream, 1 white. Why?

The fact that, when a yellow guinea pig is crossed with a white offspring, turns out to be cream, speaks of the manifestation of the phenomenon of incomplete or intermediate dominance. This is exactly what the splitting in the second generation proves. We confirm with the crossing scheme.

Let A be the yellow color of the coat, then a is white, and Aa is cream.

RR f Aa (k) x m Aa k)

m / f A a A AA (g) Aa (j) a Aa (j) aa (b)
By phenotype:

25% are yellow;

50% – cream;

25% are white.

In this case, yellow and white individuals are homozygotes, and cream ones are heterozygotes.