Sex-biased gene discovery from the gonadal transcriptomes of the large yellow croaker (Larimichthys crocea)

Abstract

The investigation of sex determination in fish is not only of great scientific value, but also has important practical significance, especially in fishes grown in aquaculture exhibiting obvious growth-related sexual dimorphism, such as the large yellow croaker (Larimichthys crocea). While growth of the female large yellow croaker is faster than that of the male, little information exists on the mechanisms that drive the differentiation of the testis and ovary in this species. In this study, the gene expression profiles of large yellow croaker testis and ovary were analysed using RNA-Seq technology. A total of 222 million reads were mapped to the reference genome (89.80%). The differential gene expression analysis identified 13 genes specifically expressed in ovary and 897 specific to testis. Among these, were candidate sex determining genes, such as Dmrt1, Gsdf, Sox9, Amh. This study explored gene expression profiles in large yellow croaker gonads at the transcriptome level by RNA-Seq technology. We found many DEGs related to the development of each specific organ, including the candidate testis differentiation genes Dmrt1, Gsdf, Sox9, Sox3, Amh and ovary differentiation gene Foxl2 by analogy with other fish species, providing essential foundation clarifying the molecular mechanism involved in early sex differentiation. Keywords: Sex differentiation, Large yellow croaker, Transcriptome, Gonad, Gene expression