Abstract：Abstract Myostatin (MSTN) is the negative regulator in the muscular development. MSTN gene has great potential application values in genetic breeding. Acrossocheilus fasciatus is a kind of economic fish which has great prospects for the development, but its growth is slow. In order to clarify the gene characteristic and seek molecular markers associated with growth traits, the MSTN gene of A. fasciatus was cloned, detected its expression level in different tissues and screened single nucleotide poly morphism (SNP) sites. The full length of MSTN cDNA sequence was 2 163 bp, including a 1 128 bp open reading frame (ORF) that encoded 375 amino acids. The putative MSTN protein of A. fasciatus had the essential characteristic of vertebrate MSTN, such as the proteolytic site RIRR and nine conserved cysteines in the C-terminal. Sequence alignment showed that homology of MSTNs were greater than 80% among different teleost, and fish had low homology (approximately 65%) with other vertebrates. A. fasciatus MSTN was highly homologous with other Cyprinidae fish (＞96.5%). The phylogenetic tree based on MSTN amino acids showed all the fish clustered together, which was seperated from other vertebrates. A. fasciatus was located in the cluster of Cyprinidae. Semi-quantitative RT-PCR showed that there were high level of MSTN mRNA expression in brain and muscle, weak expression in liver and intestine, and no expression was detected in spleen, kidney, gill, fin and heart. The full-length of MSTN gene DNA sequence was 5 828 bp, which contained 3 exons and 2 introns. Ten SNPs sites were detected in the second intron, but there was no significant correlation (P＞0.05) between these SNP and growth traits (body weight and body length). These results provide reference for the function research of MSTN gene and seeking molecular markers associated with growth traits in A. fasciatus.
