Let's say that during your labs you identify two mutant strains of drosophila that exhibit a no eye phenotype (eyeless). Further test show that both mutant phenotypes are recessive. You cross the two strains with each other. All the F1 offspring are phenotypically wild-type. After intercrossing these F1 flies (F1 X F1), however, you observe 562 wild-type flies and 438 eyeless flies in the F2 generation. What is the most likely explanation for these results?
a. The two mutants affect different genes involved in eye development.
b. This F2 ratio results suggests that there is some sort of variable penetrance in the wild type allele.
c. There is not enough information to explain the results.
d. The F1 cross is a test cross giving approximate 1:1 ratios of wild type to eyeless.
e. The two mutants carry alleles affecting the same gene needed for eye formation.