A woman is phenotypically normal, but her father had the sex-linked recessive condition of red-green color blindness. If she has children with a man with normal vision, what is the probability that their first child will have normal vision and their second child will be color blind?

Question

Quizplus · Accepted Answer

The woman is a carrier for red-green color blindness, as her father had the condition. The man has normal vision, so he does not carry the gene for color blindness. The probability that their first child will have normal vision is 1/2, as the child can inherit either the normal allele from the father or the carrier allele from the mother. The probability that their second child will be color blind is 1/4, as the child can only inherit the color blindness allele from the mother and the normal allele from the father. The probability of both events occurring is 1/2 x 1/4 = 1/8 = 3/16.

A Woman Is Phenotypically Normal, but Her Father Had the Sex-Linked