Polydactyly is expressed when an individual has extra fingers and/or toes. Assume that a man with six fingers on each hand and six toes on each foot marries a woman with a normal number of digits. Having extra digits is caused by a dominant allele. The couple has a son with normal hands and feet, but the couple's second child has extra digits. What is the probability that their next child will have polydactyly?
A) 3/4
B) 1/32
C) 7/16
D) 1/2
E) 1/8

Question

Quizplus · Accepted Answer

The man must be heterozygous for the polydactyly trait (Pp) since he has a child with normal digits (pp). The woman is homozygous recessive (pp). The probability of their next child having polydactyly is 1/2, as there is a 50% chance of inheriting the dominant allele (P) from the father.

Polydactyly Is Expressed When an Individual Has Extra Fingers And/or