slides
Androgen receptor expression in the human and rat urogenital tract
- Publication date
- 25 October 1995
- Publisher
- Sexual differentiation is a sequential process beginning with the establishment of the
genetic sex at fertilization of the oocyte by a sperm. In the fertilized oocyte the testis
determining gene drives the process of sexual differentiation into the male direction. In
normal development the SRY gene that codes for the testis determining factor is located on
the short arm of the Y chromosome. In males the indifferent gonad will turn into a testis, in
females the gonad becomes an ovary. In the mammal, the heterogametic sex (XY) is male
and the homogametic sex (XX) is female. The male phenotype is formed as a consequence of
endocrine secretions of the testis. Female characteristics will develop in the presence of an
ovary or if no gonads are present.
The presence or absence of the testis determining gene and the presence of XY or XX
chromosomes are known as genetic sex and chromosomal sex, respectively (Table 1).
Subsequently, the type of gonad depicts the gonadal sex, the male or female anatomic
characteristics form the phenotypic sex. Ambiguous differentiation of sexual characteristics
occurs if one of the steps is disturbed or lacking.