What percentage of male offspring will have white eyes if a purebred red-eyed female fruit fly is crossed with a white-eyed male?

To understand the inheritance pattern of eye color in fruit flies, particularly Drosophila melanogaster, we must first recognize that eye color is controlled by an X-linked gene. In this scenario, we have a purebred red-eyed female fruit fly, which possesses two copies of the allele for red eyes (denoted as XX), and a white-eyed male, who has one X chromosome with the white eye allele and one Y chromosome (denoted as XY).

When these two flies cross, the female can only contribute X chromosomes that carry the allele for red eyes. The male contributes either his X chromosome (with the white eye allele) or his Y chromosome. The potential offspring from this cross can be outlined as follows:

1. Male offspring receive their Y chromosome from their father and one X chromosome from their mother. Since the mother only provides the X chromosome for red eyes, all male offspring (XY) will inherit the red-eye trait from their mother.

2. Female offspring receive an X chromosome from both parents. The daughters will inherit one X with the red eye allele (from the mother) and one X with the white eye allele (from the father), resulting in red-eyed females that are heterozygous (X with red eyes and