A man has extra digits (six fingers on each hand and six toes on each foot). His wife and their daughter have the normal number of digits (five fingers on each hand and five toes on each foot.) Having extra digits is a dominant trait. The couple's second child has extra digits. What is the probability that their next (third) child will have extra digits?
A) 1/2
B) 1/16
C) 1/8
D) 3/4

Question

Quizplus · Accepted Answer

The trait for extra digits is dominant, so the man must be heterozygous (Dd) since his daughter is normal (dd). The wife is normal (dd). The probability of their next child having extra digits is 1/2 (Dd or dd).

A Man Has Extra Digits (Six Fingers on Each Hand