Chapter 7, Problem 12QP

Mutations Can Uncouple chromosomal Sex from Phenotypic Sex

Discuss whether the following individuals (1) have male or female gonads, (2) are phenotypically male or female (discuss Wolffian/Müllerian ducts and external genitalia), and (3) are sterile or fertile.

1. a. XY, homozygous for a recessive mutation in the testosterone biosynthetic pathway, producing no testosterone
2. b. XX, heterozygous for a dominant mutation in the testosterone biosynthetic pathway, which causes continuous production of testosterone
3. c. XY, heterozygous for a recessive mutation in the MIH gene
4. d. XY, homozygous fora recessive mutation in the SRY gene that abolishes function