Transcriptomic profiling reveals sex-specific gene expression patterns in Eriocheir sinensis gonads.

The Chinese mitten crab (Eriocheir sinensis) exhibits prominent sexual dimorphism with important economic implications, yet the molecular mechanisms underlying its sex determination and regulation remain poorly characterized. Here, we present the first comparative gonadal transcriptome analysis of E. sinensis to identify sex-related genes. High-throughput sequencing of testicular and ovarian tissues identified 5894 differentially expressed genes (DEGs), including 2581 female-related and 3313 male-related DEGs. Functional enrichment analyses revealed critical pathways governing crustacean sexual regulation, such as Steroid hormone biosynthesis pathway and GnRH signaling pathway. Moreover, a protein-protein interaction (PPI) network of 65 sexual regulation-related DEGs was constructed. Accordingly, Estradiol 17-beta-dehydrogenase 8 (HSD17B8), a dual-function enzyme in estrogen/testosterone metabolism, and Heat shock protein 90 (HSP90), a molecular chaperone stabilizing estrogen receptors, were identified as hub genes. In addition, experimental validation via RT-qPCR showed strong concordance with transcriptomic data, confirming the reliability of sex-biased expression patterns. The results of this study provide valuable resource of target genes for future studies on the molecular mechanisms underlying sex determination and regulation in E. sinensis.