Schematic representation of putative exon–intron structures and sex-specific splicing patterns of the sex determination genes.

(A) Schematics of putative exon-intron structures of the sex determination genes in T. dichotomus. Orange box, RRM (RNA binding motif); Green box, CAM (C, Ceratitis; A, Apis; M, Musca) domain [34, 47], which is conserved in all tra orthologs identified in other insects except for those in Drosophila species and the sandfly (Phlebotomus papatasi) [48]; Light blue box, Med29 (mediator complex subunit 29) domain; Brown box, DM (Doublesex/Mab-3 DNA-binding) domain; Yellow box, OD2 (Oligomerization dmain 2); Black bars, template sequences for dsRNA synthesis; Green bars, the amplified regions in qRT-PCR analysis; Light green bars, the amplified region to test sex-specific splicing variants; Magenta lines, translation start sites; Purple lines, stop codons. (B) Evaluation of expression and sex-specific splicing patterns in the sex determination genes in male and female prepupal head horn primordia. Template cDNAs were derived from prepupal horn primordia at 72 h APF. Tdic-RpL32 was used as an internal control for RT-PCR. Blue arrows, PCR products with male specific splicing variants; Magenta arrows, PCR products with female specific splicing variants; Black arrows, PCR products amplified in both sexes.