Analysis of Horse Myostatin Gene and Identification of Single Nucleotide Polymorphisms in Breeds of Different Morphological Types

Myostatin, encoded by MSTN gene, is one negative modulator of muscle mass. We characterized horse (Equus caballus) MSTN gene and identified and analysed single nucleotide polymorphisms (SNPs) in breeds of different morphological types. Sequencing of coding, untranslated, intronic and regulatory regions of MSTN gene in 12 horses from 10 breeds revealed seven novel SNPs: two in the promoter, four in intron 1 and one in intron 2. The SNPs of the promoter (GQ183900:g.266T>C and GQ183900:g.156T>C, the latter located within a conserved TATA-box like motif) were screened in 396 horses from 16 breeds. The g.156C allele presented higher frequency in heavy muscled (brachimorphic and mesomorphic with draft-type qualities) than in lighter muscling breeds (Italian Trotter and Thoroughbred). This difference and analysis of molecular variance on haplotypes might indicate that the promoter polymorphisms are associated with variability of morphology types related to size, structure and muscle mass of the horse breeds.