A student crosses two true-breeding fruit fly stocks: red-eyed long-winged (RRLL) females x white-eyed vestigial-winged (rrll) males. All F1 are red-eyed long-winged. F1 are interbred. The F2 produces 590 red long, 200 red vestigial, 195 white long, and 65 white vestigial offspring (total 1050).
What ratio of phenotypes is expected if the two genes assort independently?
- Acheck_circle
9:3:3:1
- B
3:1
- C
1:2:1
- D
1:1:1:1
Explanation
A dihybrid cross of two heterozygotes (RrLl x RrLl) with independent assortment yields a 9:3:3:1 ratio of phenotypes for the four combinations of the two traits.