Question

Assume that the genes for tan body and bare wings are 15 map units apart on chromosome II in Drosophila. If a tan-bodied, bare-winged female was mated to a wild type male and the resulting F1 phenotypically wild type females were mated to tan-bodied, bare- winged males. Of 1000 offspring, what would be the expected number of flies that are tan but have normal wings

Answer 1

Answer:

WILD TYPE= 425;

TAN-BARE= 425;

TAN= 75;

BARE= 75

Explanation:

Fifteen map units apart implies that 15% of the offspring are products of recombination.

Out of 1000 offsprings, therefore 15% of 1000= 0.15 × 1000=150

150 offsprings are products of recombination.

100-15 =85%

Therefore, 85% of the offspring are parental.

So, if tan-bodied, ware-winged female was mated with wild-type male resulting in F1 phenotypically wild-type females were mated to tan-bodied, bare-winged males.

The expected number of offsprings that are tanned but have normal wings would be:

Wild type= 50% of 850

0.50 × 850 = 425

Tan-bare= 50% of 850

0.50 × 850 = 425

tan= 50% of 150

0.50×150= 75

Bare= 50% of 150

0.50×150=75