Developmental Link between Sex and Nutrition; doublesex Regulates Sex-Specific Mandible Growth via Juvenile Hormone Signaling in Stag Beetles
(A) Predicted gene models C. metallifer doublesex (Cmdsx) from transcripts. Four alternative splice variants were found and designated Cmdsx splice variants A, B, C and D. The coding sequence is in light gray, the conserved DM domain is in black, and the predicted dsx dimer formation site is in dark gray. Arrows indicate forward and reverse primer locations on the sequences and the region that was synthesized for dsRNA is indicated. (B) RT-PCR using exon-specific primers. Template cDNAs were derived from Stage 2 mandibles of both sexes. Transcripts A and B are male specific in expression and C and D are female specific in expression. (C) Temporal and spatial expression patterns of Cmdsx exon 1 in developing mandibular and maxillar tissues from small males, large males and females during the prepupal period. Total Cmdsx expression is shown by exon 1 as it is common to all four Cmdsx splice forms. Maxillae were used as a control trait as they show isometric growth both in males and females and do not show strong sexual dimorphism in C. metallifer. Relative expression of exons 4, 6, 8, & 9 are shown from Stage 2 male and female mandibles. The averages and 95% confidence intervals of three technical replicates are shown. For each exon, different small-case letters indicate significant differences (Tukey-Kramer test, P<0.05).