Homework Sourse2 You caught a Drosophila female with red normalshaped compo
#2: You caught a Drosophila female with red normal-shaped compound eyes (wild type) in wild. This female had been apparently mated with a male with unknown genotype before you caught her. After keeping her in a culture medium, she laid about 200 eggs. About 10 days later, adult flies came out.
All flies had red eyes. All females had malformed small compound eyes. On the other hand, all males had wild type-shaped compound eyes. Infer the genotypes of this female and the male that mated with this female in wild.
Solution
The fact that all progeny of a particular sex had only one type of eyes suggests that the trait is sex-linked. Therefore, the female parent must have had the genotype: RRXsXs, and the male parent must have had the genotype: RRXSY.
(R denotes the wild-type allele for red eye; Xs denotes the X-linked recessive wild-type allele for normal-shaped eyes, XS denotes the mutant, dominant X-linked allele for malformed eyes).
Punnett square:
The female will produce only single type of gamete i.e. RXs, whereas the male would produce two types of gametes viz. RXS and RY.
| RXs | |
| RXS | RRXSXs (all females red-eyed, malformed eyes) |
| RY | RRXsY (all males red-eyed, normal eyes) |
