Fig. 1

Organization and splicing of D. melanogaster, An. gambiae, Cx. quinquefasciatus and Ae. aegypti doublesex genes. Homologous exons (colored boxes) are aligned vertically, with numbers placed above. Numbers within boxes represent the exon size, while those on a diagonal below represent intron size. Yellow bars (not placed to scale) represent stop codons. Solid splice guides follow the female-specific spliceform, while dashed guides represent splicing in the male-specific form. Common exons are shown in green, the female-specific exon 5 in dark red, and male-specific (UTR in female) exons in blue. The green/white stippled box adjacent to exon 4 denotes the extension of the reading frame to the alternate splice donor. Black arrows denote TRA/TRA2 binding sites, purple arrows denote putative TRA2-ISS motif clusters, blue arrows signal RBP1 type-b motif clusters and green arrows signal Nasonia-like NvTRA binding site location. Asterisks are placed above weak splice acceptors