Holt Modern Biology 1st Edition by John Postlethwait ,Janet Hopson

Exercise 14

Colorblindness is a recessive, sex-linked trait. A woman and a man, both with normal vision, have three daughters with normal vision. One of the daughters marries a man with normal vision, and they have a son who is colorblind.
Part A Which parent of the son is the carrier of the trait? Explain your answer.
Part B What is the likelihood that the children of a woman heterozygous for colorblindness and a colorblind man will express the trait? Explain your answer.