In humans, the sickle-cell trait is caused by a single defective allele, but sickle-cell disease only occurs in individuals that are homozygous for the sickle-cell allele.A man and woman each carry the trait, but do not have sickle-cell disease.What is the probability that their first two children will both have sickle-cell disease?
A)1/16
B)1/8
C)1/4
D)3/8

Question

Quizplus · Accepted Answer

Each child has a 1/4 chance of having sickle-cell disease (homozygous for the sickle-cell allele) when both parents are carriers. The probability that both of their first two children will have the disease is (1/4) * (1/4) = 1/16.

In Humans, the Sickle-Cell Trait Is Caused by a Single