A cross between a rose comb chicken (RRpp) and a pea comb chicken (rrPP) produces all walnut comb chickens (RrPp).This outcome is a result of
A)environmental factors.
B)two interacting gene pairs affecting one trait.
C)a gene mutation in the rose comb chicken.
D)pleiotropic effects of the P gene product.
E)continuous variation in phenotypes.

Question

Quizplus · Accepted Answer

The outcome of the cross suggests that two gene pairs, one for comb shape and one for pigmentation, are interacting to produce the walnut comb phenotype. The inheritance pattern of this trait is consistent with Mendelian genetics, specifically the principle of independent assortment. Environmental factors would not produce such clear and predictable results, and a gene mutation in the rose comb chicken would not account for the offspring's phenotype. Pleiotropy and continuous variation may be involved in other traits, but they are not relevant to this particular scenario.

A Cross Between a Rose Comb Chicken (RRpp) and a Pea