Question

Fruit flies can have one of two colors in their eyes: red or white. Red is the dominant trait while white is the recessive trait. The eye color trait is a sex-linked trait. If a male with red eyes (XRY) is crossed with a female that is heterozygous dominant for red eyes (XRXr), what are the chances that their offspring will have white eyes? (1 point)
Responses

50%
50%

100%
100%

75%
75%

25%

Answer 1

To determine the chances of the offspring having white eyes from the cross between a male with red eyes (XRY) and a heterozygous female (XRXr), we can set up a Punnett square to visualize the genotype combinations.

Here are the potential gametes from each parent:
- Male (XRY): can only provide X^R or Y
- Female (XRXr): can provide X^R or X^r

Now, we create the combinations of these gametes:

| | X^R | X^r |
|-------|-----|-----|
| X^R | X^R X^R (Red) | X^R X^r (Red) |
| Y | X^R Y (Red) | X^r Y (White) |

Now we list the possible genotypes of the offspring:
1. X^R X^R (Red eyes)
2. X^R X^r (Red eyes)
3. X^R Y (Red eyes)
4. X^r Y (White eyes)

From this cross, we find:
- 3 out of 4 combinations result in red eyes (X^R X^R, X^R X^r, and X^R Y).
- 1 out of 4 combinations results in white eyes (X^r Y).

Thus, the chance of having white-eyed offspring is 25%.

The correct response is:
**25%**