Abstract
Female common carp grow faster than male individuals, implying that rearing females could be more profitable in aquaculture. Non-coding RNAs (ncRNAs) serve as versatile regulators with multiple functions in diverse biological processes. However, the roles of ncRNAs in the sex differentiation of common carp are less studied. In this study, we investigated the expression profiles of ncRNAs, including miRNAs, lncRNAs, and circRNAs, in the gonads to comprehend the roles of ncRNAs in sex differentiation in common carp. A substantial number of differentially expressed (DE) ncRNAs in ovaries and testes were identified. Some miRNAs, notably miR-205, miR-214, and miR-460-5p, might modulate hormone synthesis and thus maintain sex. A novel miRNA, novel_158, was predicted to suppress the expression of foxl3. DE lncRNAs were associated with oocyte meiosis, GnRH signaling pathways, and steroid biosynthesis, while DE circRNA target genes were enriched in the WNT signaling pathway and MAPK signaling pathway. We also analyzed ncRNA-mRNA interactions to shed light on the crosstalk between competing endogenous RNAs (ceRNAs), which is the critical mechanism by which lncRNAs and circRNAs function. Some lncRNAs and circRNAs may be able to competitively bind novel_313, a new miRNA, and thus regulate hsd17β3. Our research will provide a valuable resource for understanding the genetic basis of gonadal differentiation and development in common carp.