Mammalian sex determination: joining pieces of the genetic puzzle.

Mammalian sex determination is controlled by the Y-linked gene SRY. Studies of sex-reversed patients and experimental data obtained with mice have identified other genes, such as DAX1, SOX9, SF1, and WT1, which take part in the process, and have suggested how these genes interact to determine the sex of a mammalian embryo. A recent paper in Nature by Swain et al. provides experimental data that basically confirm the previously proposed hypothesis that SRY acts by inhibiting the action of DSS/DAX1, which is a repressor of genes of the male pathway.