Question

mr. Christopher is colourblind and carrier for pku. What percentage of sperms possesses defective allele for both ?

Answer 1

As, Mr Christopher is a carrier for PKU, he must carry only one defective allele. Thus, the probability of a sperm to carry the defective allele would be 1/2 or 0.5. It comes out to be 0.25 that is, 25%.