Molecular characterization and expression analysis of the myostatin gene and its association with growth traits in Noble scallop (Chlamys nobilis)

Myostatin (MSTN), also called growth and differentiation factor-8 (GDF-8), is a member of the transforming growth factor-β (TGF-β) superfamily and an inhibitor of muscle differentiation and growth. In this report, we identified and characterized a MSTN gene (CnMSTN) from the scallop Chlamys nobilis. The open reading frame of CnMSTN was 1374 bp in length, encoding 457 amino acids. The structure of CnMSTN included a putative signal peptide, a TGF-β propeptide domain, and a conserved TGF-β domain. Phylogenetic analysis showed that the CnMSTN gene was clustered in the same subgroup with the MSTN gene found in Mollusca. Quantitative real-time PCR showed that the CnMSTN gene was widely expressed in all tissues tested, with the highest expression level observed in the adductor muscle. Six single nucleotide polymorphisms (SNPs) were identified in the promoter region, but no SNP was detected in the exon regions. Association analysis showed that SNP g.-579A/C had significant effects on body mass, soft-tissue mass, and adductor muscle mass. The CC and AC genotypes of g.-579A/C had significantly higher growth trait values than that of genotype AA (P < 0.05). These results suggest that CnMSTN could be used as a candidate gene for the selective breeding of C. nobilis.