Question

In flies, red eye color (Xa) is a sex-linked recessive trait. Black eyes (XA) are the normal colored eyes for flies. What are the chances
that a carrier mom and a black-eyed dad will have (hint: you must use X's and Y's):
a. a red eye male as their next offspring?
b. a black eye female as their next offspring?
2.
3
4.
5 6 7 8 9 10

Answer 1

Answer:

The correct answer is -

a. a red-eye male as their next offspring? = 25%

b. a black eye female as their next offspring? = 25%

Explanation:

The given question says that in flies the red eye color is a sex-linked recessive trait which means it will only appear in the presence of two copies of the recessive allele in females and one copy of recessive allele in male as there is only one copy of X chromosome is present in males the other chromosome is Y.

So, the genotype of carrier mom would be XaXA and normal black eye male would be XAY, then cross between these flies:

        XA          Y

Xa     XaXA    XaY

XA   XAXA     XAY

On the basis of red eye male would be XaY = 1/4 = 25%

and the black eye female would be XAXA  = 1/4 = 25%