Please help me with my Genetics homework?

Question

in Drosophila, graybody(G) is dominant over black(g) and normal wings are more dominant over short wings(w). A student performs the following cross: GgWw x ggww. Among the offspring, she finds the following: 115 gray body, normal wings; 27 graybody, short wings. 25 blackbody, normal wings; 120 black body, short wings. Should the student conclude that the genes for body color and wing shape are linked? Explain and present your reasoning.

Thank you guys :D

Answer 1

When predicting GgWw x ggww by using a punnet square, you get:
........gw all across the top...............phenotype
GW GgWw GgWw GgWw GgWw gray, normal 25%
Gw Ggww Ggww Ggww Ggww gray, short 25%
gW ggWw ggWw ggWw ggWw black, normal 25%
gw ggww ggww ggww ggww black, short 25%

Notice that each row is the same throughout, making each phenotype possible 25% of the time. That means that it is predicted the Drosophila will have about the same number of each phenotype. However, since the student found the numbers are not almost the same for all four, it means that the alleles for these traits are linked. Linked alleles mean that certain traits go together and are not independent. Since there are high and low amounts of each phenotype, it means that their alleles always stay together and are therefore linked.

Answer 2

I think I remember this crap. I think if they are not linked gray body normal wings and black body short wings should have roughly 1:1. I don't think they're linked. If they are linked they shoud deviate from ratio given by normal calculation using punnett square. If the ratio matches punnett square it probably means genes are far enough apart so they'll be separated during cross over. I think those numbers above matches punnett square prediction. So, no linkage or try it your self.

Answer 3

Yes, if they weren't linked the cross would result in equal numbers of gray normal, gray short, black normal and black short.