The proposed mode of genetic control of the orange/black color dimorphism in B. breviceps. The schematic diagram illustrates how mutations in the color locus may drive orange/black setal pigmentation changes. This model proposes that the color locus of B. breviceps may correspond to an iab genetic switch that controls iab6 lncRNA expression in adult epidermis of metasomal T5. A mutation on the locus may cause the iab6 lncRNA switch to turn off in the black-tailed form, which causes expression silencing of this lncRNA at T5. The loss of iab6 lncRNA at the metasomal T5 may then interrupt the transcriptional or translational regulation of its target Hox genes, most likely Abd-B. Interruption of normal function of this Hox gene at T5 may then cause a homeotic shift of T5 setal identity toward the more anterior, black-colored T4 or T3, leading to the orange-to-black shift. Dashed arrows and question marks indicate untested alternative hypothesis on how ncRNA silencing may interrupt Abd-B during transcription and translation. EE, embryo epidermis; AE, adult epidermis.