Tall pea plants are crossed to short, and the progeny are medium height. The F₁plants are crossed together, but the progeny observed among the F₂ have nine different size classes. This result is best explained by A) the existence of pleiotropic alleles. B) incomplete dominance. C) codominance. D) an increased number of phenotypes due to multiple alleles. E) epistasis.

Question

Quizplus · Accepted Answer

The result of multiple size classes among the progeny suggests that there are more than two alleles involved in determining height, leading to an increased number of phenotypes. This is consistent with option D, which describes multiple alleles. Pleiotropy, incomplete dominance, and codominance would result in fewer phenotypes. Epistasis could affect the expression of alleles, but it would not lead to an increased number of phenotypes.

Tall Pea Plants Are Crossed to Short, and the Progeny