The genotypes and phenotypes that result from a cross of AA and Aa (A = normal pigmentation and a = albinism) are
A) phenotypes - all normal; genotypes - 50% homozygous dominant and 50% heterozygous.
B) phenotypes - 50% normal and 50% albino; genotypes - all heterozygous.
C) phenotypes - 75% norma and 25% albino; genotypes - 75% heterozygous and 25% homozygous.
D) phenotypes - all albino; genotypes - 50% heterozygous and 50% homozygous recessive.

Question

Quizplus · Accepted Answer

This cross involves a homozygous dominant parent (AA) and a heterozygous parent (Aa). The possible gametes of the AA parent are all A, and the possible gametes of the Aa parent are A and a. The Punnett square for this cross will show that all offspring will have at least one A allele, resulting in normal pigmentation. The genotypes will be 50% AA (homozygous dominant) and 50% Aa (heterozygous), as each parent can only contribute one allele to each offspring.

The Genotypes and Phenotypes That Result from a Cross of AA