[The genetics of sex determination]

The male sex determination controls the testis determination and differentiation. So far more than a dozen of gene have been characterised, including the primary Y male sex determinant: SRY gene. All the genes encode transcription factor except FDF9 which encodes a growth factor allowing mesonephritic cell to divide and migrate to the mesenchyme. All these gene products are sensitive in man (but not in the mouse model) to gene dosage: haplo-insufficiency and or duplication of these genes all lead to sex reversal. Today, we still do not know how their products are epistatic in the sex determining cascade. So far no ovary sex determining gene has been characterised.