Question

Cross a male with red eyes with a female that has white eyes in a Punnett square. Find the genotypes and phenotypes for each.

a) Genotypes: X^RY, X^rX^r; Phenotypes: Red eyes, white eyes
b) Genotypes: X^RY, X^RW; Phenotypes: Red eyes, white eyes
c) Genotypes: X^rX^r, X^rX^RW; Phenotypes: White eyes, carrier
d) Genotypes: X^RW, X^RW; Phenotypes: Red eyes, red eyes

Answer 1

Crossing a male fruit fly with red eyes (X^WY) and a female with white eyes (X^wX^w) results in heterozygous females with red eyes (X^WX^w) and males with white eyes (X^wY).

Step-by-step explanation:

When crossing a male fruit fly with red eyes with a female with white eyes, it is important to understand that eye color in fruit flies (Drosophila) is an X-linked trait. The white-eyed phenotype is recessive, and the red-eyed phenotype is dominant. We use w for the white-eye allele and XW for the wild-type, red-eye allele.

In this scenario, the male has red eyes and the female has white eyes, indicating that the male's genotype is XWY and the female's genotype is XwXw. A Punnett square would show all female offspring are heterozygous with red eyes XWXw and all male offspring have white eyes XwY. This is because females receive one X chromosome from each parent, whereas males receive the Y chromosome from their father and the X chromosome from their mother.