Question

Albinism is an autosomal recessive disorder. Two parents with normal pigmentation have an albino child. What is the probability that their next 4 children will consist of two albinos and two with normal pigmentation, in any order?

Answer 1

Answer: 0.0351

Step-by-step explanation:

For two normal parents to give birth to an albino child means that both parents are heterozygous for albinism (Aa). And therefore the possible genotype for any of their children be AA Aa Aa and aa.

This means 1/4 will be totally free from the albinism, 2/4 will be carriers like their parents and have normal pigmentation and 1/4 will be albino.

The probability of normal pigmentation is 3/4 and 1/4 for albino.

Therefore the probability that in 4 children two will be albinos and the other two will have normal pigmentation is 1/4 * 1/4 * 3/4 * 3/4 = 9/256 = 0.0351