Question

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene. Two parents

with normal pigmentation have an albino child. What is the probability that their next child will be
albino?
A) 1/16
B) 1/2
C) 1/3
D) 1/4
E) 3/4

Answer 1

The probability that the next child of two parents with normal pigmentation will be albino is 1/4 (D).

Step-by-step explanation:

The probability that the next child of two parents with normal pigmentation will be albino is 1/4 (D).

Albinism is caused by an autosomal recessive gene. This means that both parents carry a normal pigmentation gene as well as a recessive albino gene. In order for their child to be albino, both parents must pass on the albino gene. When considering the Punnett square, there is a 1/4 chance of both parents passing on the albino gene, resulting in an albino child.

The albino child would have the genotype aa, while the parents would have the genotypes Aa and Aa. When these genotypes are crossed in the Punnett square, the resulting possible genotypes are: AA, Aa, Aa, and aa. This results in a 1/4 chance of having an albino child.