# De Novo Assembly, Characterization and Comparative Transcriptome Analysis of the Mature Gonads in Megalobrama terminalis

## TL;DR

This study analyzes the gonadal transcriptomes of a South China fish to identify genes involved in sex differentiation and reproduction.

## Contribution

The first comparative transcriptome analysis of gonads in Megalobrama terminalis, identifying key genes related to gonadal development.

## Key findings

- 84,886 unigenes were assembled, with 42,322 annotated to major databases.
- 14,972 differentially expressed genes were identified, including those related to steroidogenesis and gametogenesis.
- Results provide insights into genes and pathways involved in gonadal differentiation in teleost fish.

## Abstract

Megalobrama terminalis is an economically important fish indigenous to South China. However, there is less research on gonadal differentiation and development in M. terminalis. In this study, the gonadal transcriptome of female and male M. terminalis was analyzed for the first time. Many differentially expressed genes (DEGs) relevant to steroidogenesis, gonadal differentiation and development, and gametogenesis were identified after comparing the transcriptomes of male and female gonads. The annotation results of DEGs showed that some reported genes related to gonadal differentiation in teleost fishes may play essential roles in M. terminalis. Results of this study will provide data to support the reproduction and breeding of M. terminalis.

Megalobrama terminalis is a significant aquatic fish in South China, renowned for its tasty meat. Nonetheless, related studies are deficient concerning the gonadal development of M. terminalis. This paper presents the first comparative transcriptome analysis of the gonads of female and male M. terminalis. A total of 84,886 unigenes were assembled, with 42,322 effectively annotated to the Nr, SwissProt, KEGG, KOG, and GO databases. Furthermore, comparative transcriptomic analysis of M. terminalis was conducted to examine its gonadal development. A total of 14,972 differentially expressed genes (DEGs) were discovered. In the testis, the expression of 11,928 unigenes was significantly upregulated, while 3044 were significantly downregulated. Numerous DEGs associated with steroidogenesis, gonadal differentiation and development, and gametogenesis in teleost fish were identified. The results provide empirical support for further study of genes and pathways associated with sex determination and gonadal differentiation in teleost fish.