A woman and her husband are both heterozygous carriers of an autosomal recessive condition. What is the possibility that their offspring will have the condition?
A)0%
B)25%
C)50%
D)75%
E)100%

Question

Quizplus · Accepted Answer

Since both parents are heterozygous carriers, they each have one copy of the mutated gene and one copy of the normal gene. During reproduction, there is a chance that each parent will pass on the mutated gene to their offspring. The Punnett square for a heterozygous cross shows that the probability of the offspring inheriting two copies of the mutated gene (and therefore having the condition) is 25%, while the probability of inheriting one mutated gene and one normal gene (and being a carrier like the parents) is 50%. The probability of inheriting two normal genes is also 25%, and this would mean that the offspring would not have the condition and would also not be a carrier.

A Woman and Her Husband Are Both Heterozygous Carriers of an Autosomal