Novel Single Nucleotide Polymorphisms and Haplotype of MYF5 Gene Are Associated with Body Measurements and Ultrasound Traits in Grassland Short-Tailed Sheep

Myogenic factor 5 plays active roles in the regulation of myogenesis. The aim of this study is to expose the genetic variants of the MYF5 and its association with growth performance and ultrasound traits in grassland short-tailed sheep (GSTS) in China. The combination technique of sequencing and SNaPshot revealed seven SNPs in ovine MYF5 from 533 adult individuals (male 103 and female 430), four of which are novel ones located at g.6838G > A, g.6989 G > T, g.7117 C > A in the promoter region and g.9471 T > G in the second intron, respectively. Genetic diversity indexes showed the seven SNPs in low or intermediate level, but each of them conformed HWE (p > 0.05) in genotypic frequencies. Association analysis indicated that g.6838G > A, g.7117 C > A, g.8371 T > C, g.9471 T > G, and g.10044 C > T had significant effects on growth performance and ultrasound traits. The diplotypes of H1H3 and H2H3 had higher body weight and greater body size, and haplotype H3 had better performance on meat production than the others. In addition, the dual-luciferase reporter assay showed that there are two active regions in the MYF5 promoter located at -1799 similar to -1197 bp and -514 similar to-241 bp, respectively, but g.6838G > A and g.7117 C > A were out of the region, suggesting these two SNPs influence the phenotype by other pathway. The results suggest that the MYF5 gene might be applied as a promising candidate of functional genetic marker in GSTS breeding.