Question Detail
Question
Following Mendel's law, what would the phenotypic ratio of a homozygous pea crossed with a heterozygous pea be? a. 1:3 b. 3:1 c. 2:2 d. 1:2:1
Correct Answer
Option C is the correct answer.
Detailed Explanation
Consider a cross between a homozygous dominant (AA) and a heterozygous (Aa). The gametes from AA are all A. From Aa, half are A, half are a. The offspring genotypes are AA and Aa in a 1:1 ratio. If A is dominant, all offspring will show the dominant phenotype. So the phenotypic ratio is 1:0? That's not an option. If it's homozygous recessive (aa) crossed with heterozygous (Aa), gametes: a from aa, and A and a from Aa. Offspring: Aa and aa in 1:1 ratio. Phenotypes: 1 dominant : 1 recessive, which is 1:1, or 2:2. So C is 2:2, which is the same as 1:1.
Hint
It's a 1:1 phenotypic ratio.