What phenotypic ratio would you expect as a result of a test cross between a dihybrid organism and one that is homozygous recessive for alleles at two independent loci?
A)3:1
B)1:2:1
C)1:1:1:1
D)9:3:3:1
E)9:4:2:1

Question

Quizplus · Accepted Answer

In a dihybrid organism, if we assume the two independent loci are AaBb, the gametes produced will be AB, Ab, aB, and ab. When these gametes are crossed with a homozygous recessive individual (aabb), the resulting phenotypic ratio will be 1:1:1:1 for the four possible combinations of offspring genotypes (AaBb, Aabb, aaBb, aabb). Therefore, the answer is C (1:1:1:1).

What Phenotypic Ratio Would You Expect as a Result of a Test