Assume that a black guinea pig crossed with an albino guinea pig produced 5 black offspring.When the albino was crossed with a second black guinea pig,4 black and 3 albino offspring were produced.What genetic explanation would apply to these data?
A) albino = recessive; black = recessive
B) albino = dominant; black = incompletely dominant
C) albino and black = codominant
D) albino = recessive; black = dominant
E) None of the answers listed are correct.

Question

Quizplus · Accepted Answer

The black guinea pig must be homozygous dominant (BB) and the albino guinea pig must be homozygous recessive (bb). The offspring from the first cross would all be heterozygous (Bb) and black in phenotype. When the albino is crossed with a second black guinea pig (also likely heterozygous), the resulting offspring would have a 1:1 ratio of black (Bb) to albino (bb) offspring, as predicted by a Punnett square for a cross between a heterozygous black guinea pig (Bb) and a homozygous recessive albino guinea pig (bb).

Assume That a Black Guinea Pig Crossed with an Albino