In fruit flies, the gene for red eyes (r) is dominant and the gene for sepia eyes (r) is recessive. if a red eyed heterozygous fly (rr) mates with a sepia eyed homozygous fly (rr) what are the possible genotypes of their offspring?

a. rr only

b. rr, rr, and rr

c. rr and rr

d. rr and rr

The possible genotypes of the offspring is Rr and rr.

Option C

Explanation:

C.Rr and rr ‘R’ represents a dominant allele for red eye and ‘r’ represents recessive allele for sepia eyes. Homozygous means combination of identical alleles whereas heterozygous means combination of two different type of allele.

When crossing takes place between two individual ‘Rr’ and ‘rr’ then possible outcomes becomes two offspring of ‘Rr’ (heterogeneous red eye), two offspring of ‘rr’ (homogeneous spia eye). So out of 4 offspring 2 will be i.e. 50% heterogeneous red eye and 2 will be i.e. 50% homogenous sepia eye.

i would say it is