Abstract
The process of sex determination in mammals normally unfolds in three distinct stages:
(1) establishment of chromosomal sex at fertilization (XX or XY); (2) commitment to
the appropriate pathway of gonadal differentiation with respect to chromosomal sex,
through the action (or absence) of the Y chromosome gene SRY; and (3) correct development of secondary sexual characteristics, including internal
and external genitalia, in accordance with gonadal sex. At any of these three steps,
the process of sex determination can go awry, leading to disorders of sexual development.
In this article, we review the typical mechanism and process of mammalian sex determination,
with an emphasis on the well-characterized mouse and human models. We also consider
aberrant mammalian sex determination, focusing on examples of sex reversal stemming
from gene defects.
Keywords
sex determination - sex chromosomes - SRY - sex reversal - mammal - DSD