Whole-genome resequencing reveals novel sex-related markers and candidate gene in the Chinese soft-shelled turtle (Pelodiscus sinensis)

An apparent sexual dimorphism, such as growth rate and immunocompetence, is observed in the Chinese soft-shelled turtle (Pelodiscus sinensis). The identification of sex-related markers and candidate genes holds significance for the sex-controlled breeding of P. sinensis. In this study, through an integration of whole-genome resequencing and Sanger sequencing, 21 female-specific single nucleotide polymorphisms (SNPs) were identified. Based on these SNPs, the rapid and cost-effective molecular methodologies for genetic sex identification in P. sinensis were established. Of note, 19 validated SNPs are located within the zinc and ring finger 3 (ZNRF3) gene, which has been reported to be testis-determining in mammals. Cloning of the ZNRF3 gene from P. sinensis (PsZNRF3) and analysis of its expression profile in tissues and in response to sex steroid hormone treatment demonstrated exhibiting a female-biased expression pattern. These findings not only provide molecular markers for sex-controlled breeding in P. sinensis but also open up a solid basis for revealing the sex-determination mechanism of this species.