Question

If a female fruit fly, heterozygous for red eyes (XRXr) is crossed with a white-eyed male (XrY), what percent of their offspring would have white eyes?

A. 0%
B. 25%
C. 50%
D. 75%


Im so confused on how to pair this up.

Answer 1

the answer is b. 25 percent

Answer 2

B. 25%

Step-by-step explanation:

In this cross, the female fruit fly is heterozygous for red eyes, meaning that she has one copy of the dominant red eye gene (XR) and one copy of the recessive white eye gene (Xr). The male fruit fly has white eyes because he carries two copies of the recessive white eye gene (XrY).

When the two flies mate, their offspring will inherit one copy of the X chromosome from the female and one copy of the Y chromosome from the male. Since the female is heterozygous for the eye color trait, each of her offspring has a 50% chance of inheriting the red eye gene and a 50% chance of inheriting the white eye gene. If an offspring inherits the white eye gene from both parents, it will have white eyes.