In Drosophila, a cross was made between a yellow- bodied male with vestigial (not fully developed) wings and a wild-type female (brown body). The F1 generation consisted of wild-type males and wild-type females. F1 males and females were crossed, and the F2 progeny consisted of 16 yellow-bodied males with vestigial wings, 48 yellow-bodied males with normal wings, 15 males with brown bodies and vestigial wings, 49 wild-type males, 31 brown-bodied females with vestigial wings, and 97 wild-type females. Explain the inheritance of the two genes in question based on these results.

These proportions are similar to 1/4 vestigial, 3/4 normal wings. In addition, males and females have the same amount of individuals with vestigial wings. This suggests that the wing shape gene is autosomal, with the allele vg+ being wild-type and dominant over the vestigial vg allele..

Body color

64 yellow-bodied males, 0 yellow-bodied females
16 + 48 = 64 individuals have yellow bodies
15 + 49 + 31 + 97 = 192 individuals have brown (WT) bodies.

The ratios are also 1 yellow : 3 brown, but there's a difference between males and females. This suggests that the gene that determines body color is sex-linked.

With this hypothesis, let's do the crosses considering the genotypes:

1) Parents: XʸY vg vg X Xʸ⁺Xʸ⁺ vg+ vg+

F1: Xʸ⁺Y vg vg+ and Xʸ⁺Xʸ vg vg+ (all wild-type)

2) F1xF1 gives us the offspring predicted in the Punnett Square, which matches the proportions observed in the F2.