Question

If you had two guinea pigs of opposite sex, both homozygous, one black and one brown, but you didn't know which was the dominant characteristic, how could you be certain that the guinea pigs are truly homozygous?

A) Cross them and observe the color of the offspring.

B) Perform a Punnett square.

C) Examine their pedigrees.

D) Test cross each guinea pig with a homozygous recessive individual.

Answer 1

The correct answer is D) Test cross each guinea pig with a homozygous recessive individual. A test cross is a cross between a dominant-expressing individual with an unknown genotype and a homozygous recessive individual. It helps determine whether the dominant-expressing individual is a homozygote or a heterozygote.

Step-by-step explanation:

The correct answer is D) Test cross each guinea pig with a homozygous recessive individual.

A test cross is a cross between a dominant-expressing individual with an unknown genotype and a homozygous recessive individual. By performing a test cross, we can determine whether the dominant-expressing individual is a homozygote or a heterozygote.

If the dominant-expressing individual is a homozygote, all offspring from the test cross will be heterozygotes expressing the dominant trait. However, if the dominant-expressing individual is a heterozygote, the offspring will exhibit a 1:1 ratio of heterozygotes and recessive homozygotes.