Bio
posted by Amber .
In Drosophila, sepia colored eyes are due to a recessive allele s and wild type (red eye color) to its dominant allele s+. Sepiaeyed females are crossed to pure wild type males. What phenotypic and genotypic ratios are expected if the F1 males are then backcrossed to sepiaeyed parental females?

I'm assuming that eye color is sexlinked.
X^s+= dominant
X^s= recessive
The P1 generation:
Male: X^s+, Y
Female: X^s, X^s
P1 generation cross: [X^s, X^s] x [X^s+, Y]
F1 generation
1/2X^s, X^s+
1/2X^s+, Y
Cross of F1 males with P1 females:[X^s, X^s] x [X^s, Y]
F2 generation:
1/2X^s, X^s
1/2X^s, Y