Calpastatin and myostatin genes polymorphism and their association with slaughter traits in the Gashun Soviet Merino breed grown in southern Russia

The study aimed to investigate the genetic variability of the Gashun Soviet Merino sheep breed, determining myostatin (MSTN) and calpastatin (CAST) gene polymorphism by the PCR-RFLP method. Earmark samples were collected from 200 animals, and DNA was isolated using a commercial kit. The MSTN gene had A and G allele frequencies of 0.33 and 0.67, and the CAST gene had M and N allele frequencies of 0.83 and 0.17, respectively. The frequencies of the AG and GG genotypes for MSTN and MM and MN for CAST were 0.66 and 0.34, respectively, in both. Genetic equilibrium was maintained for the CAST gene (χ²=4.1951). For the MSTN gene, the Hardy-Weinberg equilibrium was violated (χ²=24.2). The pre-slaughter body weight, hot carcass weight and slaughter weight were higher in CAST_MN genotype than CAST _MM by 4.8%, 6.5%, and 6.4%. The hot carcass and slaughter weights of lambs with the MSTN_AG genotype were higher than MSTN _GG by 4.7% in both. However, the pre-slaughter weight in the animals with the MSTN _GG genotype was higher by 3.4%. Data on the CAST and MSTN gene polymorphism and the genetic structure of the studied sheep population were obtained for the first time, their association with slaughter traits was revealed, and desirable genotypes CAST_MN and MSTN_AG were determined. The Na, Ne, Ho, He, FIS and χ2 values obtained and the absence of individuals with CAST_NN and MSTN_AA genotypes substantiated the prospect of further use of these genes in programs of genetic livestock improvement.