Most alleles of the Drosophila cut (ct) gene are stable. For example, all progeny from crossing ct1 to ct2 to yield ct1 /ct2 hetero zygotes have "cut" wings. ct1 is a strong allele with severe cutting of the wings. ct2 and another allele, ctMR2, are weaker with only moderate cutting of the wings. When ctMR2 homo zygotes are crossed to ct1 homo zygotes, three kinds of progeny are produced, 95% have a moderate cutting of the wings (as expected for ctMR2 / ct1 ), 2.5% have wild-type wings and 2.5% have more severe cut wings like ct1 homo zygotes.
a) How do you explain the high frequency of reversion to wild-type?
b) How do you explain the high frequency of progeny with the more severe cut phenotype?