In Drosophila melanogaster, the gene for eye color is located on the X chromosome. The allele for red eye color (X^w+) is dominant over the allele for white eye color (X^w). You examine a vial of 100 flies that are all offspring from a single genetic cross. You find only red-eyed females and red-eyed males present. Flies from the vial were allowed to interbreed, and in the next generation you find only red-eyed females, but you find both red-eyed and white-eyed males. The genotypes of the original parents were ____.

Question

Quizplus · Accepted Answer

The original parents were Xw+Xw+; XwY. This is because the F1 generation only had red-eyed females and red-eyed males, which means that the female parent must have been homozygous dominant (Xw+Xw+) and the male parent must have been hemizygous dominant (XwY).

In Drosophila Melanogaster, the Gene for Eye Color Is Located