Red-green colorblindness is the most common form of colorblindness and is caused by two closely linked genes located near the tip of the human X chromosome. Red blindness, or protanopia, and green blindness, or deutanopia, are recessive conditions caused by mutant alleles p and d, respectively. Between these two genes lies the locus for glucose-6-phosphate dehydrogenase (G6PD), an important enzyme found in erythrocytes. A deficient form of this enzyme is caused by the recessive allele (g).

A woman, who is phenotypically normal, marries a man who has deutanopia and protanopia and is G6PD deficient.

The couple have a daughter who is green colorblind like her father, and they have a son who is red colorblind and G6PD deficient.

(a) What is the genotype of the father?
(b) What is the most likely genotypic arrangement of the genes in the mother?
(c) The woman then has an illegitimate son with a completely normal man. The son is protanopic, deutanopic, and G6PD deficient. How is this possible?