# Establishment and Polymorphism Analysis of SNP Markers in the Gynogenic Blunt Snout Bream

## TL;DR

Researchers developed molecular markers to distinguish gynogenetic blunt snout bream from regular ones, aiding aquaculture breeding and management.

## Contribution

The study identifies and validates SNP markers specific to gynogenetic blunt snout bream for accurate identification and breeding applications.

## Key findings

- 30 SNPs associated with muscle growth and metabolism were identified in gynogenetic blunt snout bream.
- Nine polymorphic SNP markers in the myoz1a gene were validated for distinguishing GBSB from BSB.
- These markers provide a molecular tool for marker-assisted breeding and sustainable aquaculture.

## Abstract

Blunt snout bream is an economically important freshwater fish in China, and the gynogenetic blunt snout bream (GBSB) exhibits faster growth and improved nutritional quality, yet is visually indistinguishable from the common blunt snout bream (BSB), posing challenges for breeding and aquaculture management. This study aimed to develop molecular markers for the accurate identification of GBSB. Through comparative transcriptome analysis of muscle tissue, 30 candidate SNP markers were identified, with nine consistently polymorphic markers specific to GBSB being validated in 30 individuals per group. These markers are located in the muscle development-related myoz1a gene, which may provide insights into the growth advantages of GBSB. The findings offer a practical molecular tool for aquaculture breeding, supporting marker-assisted selection and the sustainable development of fish farming.

The blunt snout bream (Megalobrama amblycephala, BSB) is a freshwater economic fish with Chinese characteristics, and its genetic characteristics have unique value for studying fish evolution. The gynogenetic blunt snout bream (GBSB) obtained through distant hybridization between cross-order species, which showed a faster growth rate than the female parent, but its appearance is similar to that of BSB and is difficult to distinguish. Therefore, by comparing the transcriptome sequencing data of BSB and GBSB (SRA number: PRJNA893089, not released yet), we identified 30 SNPs associated with genes related to muscle growth, protein synthesis, and glycolysis that are unique to GBSB. Through multi-sample PCR detection and sequencing analysis, 16 SNPs with stable differences in GBSB and BSB were obtained. The polymorphism analysis of 16 SNP sites showed that 9 SNP sites were polymorphic in GBSB, which could be used to identify GBSB and its female parent, BSB. In addition, the 9 SNP sites are located in the myoz1a (myozenin 1a) gene, which is related to muscle development, and may provide insights for further study of muscle growth regulation. Therefore, this study provides candidate marker resources for GBSB germplasm resource identification and molecular marker-assisted breeding, which is beneficial for improving the efficiency and reliability of selection and breeding work.