Master genetic switches controlling sexual development in Leptinotarsa decemlineata

Sex determination is a fundamental process during early embryonic development that shapes the morphological, physiological, and behavioral sexual dimorphism of an organism. Insects, the most diverse group of animals on earth, have evolved a wide range of sex determination systems. This study investigates the sex determination and differentiation in the Colorado potato beetle (CPB), a species with an X0 sex chromosome system, by identifying key regulatory genes involved in these processes. Our findings reveal that the genes Sex-lethal (Sxl), transformer-2 (tra2), doublesex (dsx), and fruitless (fru) are highly conserved and all contribute to fertility. Among them, dsx and tra2 emerge as key genetic switches of sex differentiation in CPB: Disruption of dsx leads to feminization of male traits and abnormal female development. Additionally, tra2 appears to regulate the alternative splicing of dsx, promoting the production of the female-specific transcripts. This study highlights the pivotal roles of dsx and tra2 in CPB sex determination and provides valuable insights into the evolution and diversity of sex determination mechanisms in insects.