A transcriptional control model fordoublesex-dependent sex differentiation inNasoniawasps

The transcription factor Doublesex (DSX) orchestrates insect sex differentiation. DSX affectsDrosophila melanogastermale and female transcriptome, yet how DSX regulates gene expression in other species is poorly understood. We investigated sex-biased gene expression during the development of the parasitoid waspNasonia vitripennis, finding that more than three-quarters of its genes are sex-biased in at least one developmental point. Next, we transiently knocked downdsxexpression to infer its role in sex-specific transcriptome regulation, revealing thousands of affected genes in males and a more subtle effect in females. Finally, we performed anin vitroDNA-protein interaction assay to identify DSX binding sites on the genome and primary DSX target genes. By integrating these three datasets, we defined DSX’s regulatory function for all genes inN. vitripennis, revealing that DSX acts mainly in males as both an activator and a repressor. This male-centric model for DSX-mediated regulation is likely to apply to many other insect species.