Transcriptome analysis of the winter tick (Dermacentor albipictus) reveals sex-specific expression patterns

The winter tick, Dermacentor albipictus, is a significant ectoparasite of ruminants across North America, posing health risks to wildlife and occasionally humans. Despite its ecological importance, limited genomic resources exist for this species. This study provides the first comprehensive transcriptome analysis of D. albipictus, focusing on early-stage embryos, sexed adults, dissected ovaries, and dissected male reproductive systems. Differential gene expression analyses revealed significant sex-biased expression patterns, and functional annotations identified candidate genes involved in sex determination. Notably, we identified the first documented case of sex-specific splicing of a doublesex-like gene in chelicerates, a mechanism previously thought to be absent in this group. This discovery suggests that ticks may share more insect-like features of sexual differentiation, with implications for understanding the evolution of sex determination pathways in arthropods These transcriptome data serve as a critical resource for understanding the biology of D. albipictus and will facilitate the development of novel genetic control strategies.