Freckles are caused by a dominant allele. A man has freckles but one of his parents does not have freckles. The man has fathered a child with a woman that does not have freckles. What is the probability that their child has freckles?
A) 1/4
B) 1/3
C) 1/2
D) 2/3
E) 3/4

Question

Quizplus · Accepted Answer

The man must be heterozygous (Ff) because he has freckles (dominant trait) but one of his parents does not (homozygous recessive, ff). The woman is homozygous recessive (ff) because she does not have freckles. The possible genotypes for their child are Ff (freckles) and ff (no freckles), each with a probability of 1/2.

Freckles Are Caused by a Dominant Allele