Figure 1

Sex determination in the silkworm Bombyx mori . (a) In WZ females, Fem downregulates Masc mRNA by means of piRNA-dependent cleavage. This results in production of the female Bmdsx isoform by default. (b) In ZZ males, the absence of Fem results in functional Masc protein (green) that, in turn, results in splicing of Bmdsx into the male isoform as well as dosage compensation of Z-linked genes. Gray indicates non-functional components. Bmdsx, Bombyx mori doublesex gene; Fem, Feminizer; Masc, Masculinizer; piRNA, Piwi-interacting RNA.