A man and woman are both of normal pigmentation, but both have one parent who is albino without melanin pigmentation). Albinism is an autosomal not sex- linked) recessive trait. What is the probability that their first female child will have albinism?

Question

Quizplus · Accepted Answer

Both parents are carriers of the recessive albinism gene, as they have one albino parent each. When they have a child, each parent will randomly pass on one of their two copies of the gene to their offspring.

There are four possible combinations for the alleles that the parents can pass on to their child: Aa, Aa, aa, aa.

The only way for the child to have albinism (aa) is for both parents to pass on the recessive gene (a). Thus, the probability of this occurring is 1/4 or 25%.

Since the child is specified to be female, this does not affect the probability and the answer is still D) 1/4.

A Man and Woman Are Both of Normal Pigmentation, but Both