Question

A dominant allele K is necessary for normal hearing. A dominant allele M on a different locus results in deafness no matter what other alleles are present. If a kkMm individual is crossed with a Kkmm individual, what percentage of the offspring will be deaf?

Answer 1

The percentage that the off spring will be deaf is 75%. Two punnet squares are needed each for kkMm and Kkmm individuals. In punnet square 1, half of the genotypes are Km and km while half are Mm and kk in punnet square 2. The two punnet squares are then combined to form a final one where a quarter of the offspring are deaf.