Figure 4.—

Two models of the genetic regulation of honeybee dsx splicing. Arrows represent activation and lines with a bar indicate suppression. Active genes and interactions are in black whereas inactive ones are in gray. (A) The activator model, where the male form of dsx splicing is the default. In females, functional Csd either directly or indirectly activates the female-specific splicing to give rise to Am-dsx^F1 or Am-dsx^F2. (B) The repressor model. In females, functional Csd suppresses or inactivates R to allow the default female-type splicing to take place, whereas in males the presumed repressor R suppresses the splicing of the female-specific exon to generate the male-type mRNA, Am-dsx^M.