Question

If an organism of genotype Aa was used for a testcross, what was the genotype of the other individual used in the cross?

a. ΑΑ
b. Αα аа
c. Either Aa
d. aa
e. Either AA or Aa

Answer 1

In a testcross involving an Aa individual, the other individual is homozygous recessive, which is dd.

Step-by-step explanation:

If an organism of genotype Aa is used for a testcross, the genotype of the other individual used in the cross would have to be homozygous recessive, which is dd. A testcross is designed to reveal the genotype of an individual expressing a dominant trait by crossing it with an individual that is homozygous recessive for the same trait. In genetics, when you cross an individual with a homozygous recessive partner, it allows for the determination of whether the phenotypically dominant individual is a heterozygote (Aa) or a homozygote (AA).