Question

Bridges observed that in a cross between white-eyed females and red-eyed males, the majority of the progeny were red-eyed females and white-eyed males. However, a very small number of males had red eyes, and females had white eyes. Bridges proposed this was due to ______ in meiosis.

Answer 1

The ratio of offspring from a cross between a white-eyed male and a heterozygous red-eyed female is 1:1:1:1, with half the males having red eyes and half white, and half the females being heterozygous red-eyed and half homozygous white-eyed.

Step-by-step explanation:

The question is about the expected ratio of offspring resulting from a cross between a white-eyed male and a female that is heterozygous for red eye color in Drosophila fruit flies, a classic example of X-linked inheritance. Given a white-eyed male (XY) and a heterozygous red-eyed female (XWXw), the predicted ratio of their offspring would be a 1:1:1:1 ratio. This means that 50% of the males will have red eyes (XWY) and 50% will have white eyes (XwY). Similarly, 50% of the females will be heterozygous with red eyes (XWXw), and the other 50% will be homozygous recessive with white eyes (XwXw).