Solutions For An Introduction to Genetic Analysis Chapter 2 Problem 52P

All possible genotypes were given in the below flowchart:

Calculate the probability of having disease to the first child in the below manner:

The dominant allele is T and the recessive allele is t.

• The probability of having T/t to grandfather is

• The probability of having heterozygous condition (Tt) to woman's parent is

• The probability of having heterozygous condition (Tt) to woman is

• The probability of having heterozygous condition (T/t) to grandfather is

• The probability of having heterozygous condition (Tt) to man's parent is

• The probability of having heterozygous condition (Tt) to woman is

• The probability of having recessive allele to the child from both parents is

The probability of the first child of two first cousins having the disease = (Probability of the woman being T/t) x (the probability of the man being T/t) x (probability of donating both recessive genes from parents to the child)

Therefore, the probability of having disease to the first child of two first cousins is