Sxl controls the sexual size dimorphism (SSD) of the larval body.

(A) Schematic of the sex determination pathway in Drosophila and its control of sexual differentiation and dosage compensation. Genes/proteins active in females are displayed in red; genes/proteins active in males are displayed in blue. (B) Transheterozygous Sxl^{M1, Δ33}/Sxl^{f7, M1} mutant female adults are masculinised in terms of morphology and body size (middle panel). Both morphology and body size can be rescued by a wild-type copy of the Sex-lethal (Sxl) gene, Sxl^+tCa (right panel). (C) Sxl^{M1, Δ33}/Sxl^{f7, M1} mutant female larvae are also masculinised in terms of larval body mass, and this can be rescued by Sxl^+tCa, showing that Sxl functions to control larval SSD. Individual data points, means, and SD are plotted. Asterisks denote significant changes according to a 1-way ANOVA with multiple comparisons (** p < 0.01, **** p < 0.0001), otherwise P values >0.05 are shown. The underlying data for this figure can be found in S1 Data.