These mRNAs produce DSXM protein in males and DSXF protein in females. These proteins share a common amino acid terminal but different carboxy ends. They also come to the DNA as zinc fingers. Cline, T. and B. Meyer. Annual Review of Genetics Annual.
Sex determination is regulated by the X-chromosome counting mechanism.
Sxl is a switch gene. It controls sex determination and sex compensation. Two X-chromosomes initiate the function of Sxl. Positive feedback regulation occurs because of the pre-mRNA splicing. Genetic Feminization of Pheromones and Its Behavioral Consequences in Drosophila Males.