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 F₂ offspring of a true-breeding "fabulous" father and a true-breeding "plain" mother (aa bb) ?

Question

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 F₂ offspring of a true-breeding "fabulous" father and a true-breeding "plain" mother (aa bb) ?

Quizplus · Accepted Answer

The F2 generation from a dihybrid cross typically follows a 9:3:3:1 phenotypic ratio, which can be simplified to 9:3:4 if one of the phenotypes is not expressed.

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