KCET 2016 Biology Solved Paper

In males, a single gene for defect is able to express itself as the Y chromosome has no allele for this gene. If a male is Xh Y then he is haemophilic. The males inherit the mutation from their heterozygous mothers. These males reproduce and pass the mutation to their daughters, who are not affected as they inherit a wild-type allele from their mothers. Also, affected males never transmit the mutant allele to their sons.