Genes involved in sex determination in Drosophila melanogaster. The SXL protein regulates the female-specific splicing of the tra mRNA. The TRA protein then forms dimers with TRA-2 which regulate the sex-specific splicing of dsx mRNA. DSXF is the result of said sex-specific splicing in females, whereas DSXM is present in males. All of the above also interact with other genes in turn, in order to mediate sexual development.