A white eyed Drosophila female is crossed with a red-eyed male.Assuming the trait for eye color is sex-linked,what are the possible phenotypes of the progeny?

Question

Quizplus · Accepted Answer

If the trait for eye color is sex-linked, then it is likely that the gene for eye color is on the X chromosome. The white-eyed female must have the genotype XwXw, meaning she has two copies of the white eye gene. The red-eyed male must be XRY, meaning he has one copy of the red eye gene on his X chromosome and no copies on his Y chromosome. 
All of the resulting offspring will inherit one X chromosome from the female and either an X or a Y chromosome from the male. Therefore the possible genotypes and corresponding phenotypes are: 
- XRXR red-eyed female 
- XRXw red-eyed female 
- XwXR white-eyed male 
- XwY white-eyed male 
Since half of the offspring will inherit the X chromosome from the male and be male themselves, and since the white-eyed gene is recessive, it is possible for there to be red-eyed females and white-eyed males. Therefore, the best choice is C.

A White Eyed Drosophila Female Is Crossed with a Red-Eyed