initiates determination but no homologue of this gene exists in non-mammalian species.
Other genes of the mammalian sex-determining pathway have been identified in gonads of
different vertebrates. Sox9, Dax1, and Dmrt1 are expressed at the onset of gonadal
development in birds and reptiles. In the sea turtle Lepidochelys olivacea, a species with
temperature sex determination (TSD), Sox9 is expressed in undifferentiated gonads at male …