Chapter 3, Problem 12P

A woman’s father has ornithine transcarbamylase deficiency (OTD), an X-linked recessive disorder producing mental deterioration if not properly treated. The woman’s mother is homozygous for the wild-type allele.

a. What is the woman’s genotype? (Use D to represent the dominant allele and d to represent the recessive allele.)

b. If the woman has a son with a man who does not have OTD, what is the chance the son will have OTD?

c. If the woman has a daughter with a man who does not have OTD, what is the chance the daughter will be a heterozygous carrier of OTD? What is the chance the daughter will have OTD?

d. Identify a male with whom the woman could produce a daughter with OTD.

e. For the instance you identified in part (d), what proportion of daughters produced by the woman and the man are expected to have OTD? What proportion of sons of the woman and the man are expected to have OTD?