Suppose That the "Fabulous" Phenotype Is Controlled by Two Genes

Multiple Choice

Suppose that the "fabulous" phenotype is controlled by two genes, A and B, as shown in the following diagram. Allele A produces enough enzyme 1 to convert "plain" to "smashing." Allele a produces no enzyme 1. Allele B produces enough enzyme 2 to convert "smashing" to "fabulous." Allele b produces no enzyme 2. The A and B genes are both autosomal and assort independently.
- What will be the phenotype(s) of the F₁ offspring of a true-breeding "fabulous" father and a true-breeding "plain" mother (aa bb) ?

A) all "plain"
B) all "smashing"
C) all "fabulous"
D) "plain" females and "fabulous" males
E) "fabulous" females and "smashing" males