Question

If a female fruit fly is heterozygous with the allele for white eyes being recessive and the red eyes being dominant on the X-chromosome. She is crossed with a hemizygous red eyed male, what would be the expected ratio of male and female phenotypes if they were bred together?

Answer 1

100% red eyes because there is 50% AA and 50% Aa.

Step-by-step explanation:

To find the expected ratio of male and female phenotypes if they were bred together, you need to make a punnett square/table.

Female: A a

"A" is white eyes, which is RARE. "a" is red eyes, which is COMMON.

Male: A A

"A" is red eyes, which is COMMON.

Multiply Aa x AA by a punnett square.

GUIDE:

1. AA is common and does not carry the recessive gene of being white-eyed. 2. aa is rare and carries the recessive gene of being white-eyed.

3. Aa is common as being red-eyed since being red-eyed is dominant, but carries the recessive gene of being white-eyed.