SNPs within the beta myosin heavy chain (MYH7) and the pyruvate kinase muscle (PKM2) genes in horse

Two highly expressed skeletal muscle genes (the MYH7 gene encoding the myosin heavy chain slow/b-cardiac isoform and the PKM2 gene encoding the pyruvate kinase muscle isoforms) were investigated with the objective to identify DNA markers in horses. A panel of DNA samples from different horse breeds was analysed using a PCR-single strand conformation polymorphism (SSCP) approach. Four and two alleles were identified for the MYH7 and PKM2 loci, respectively. Mendelian inheritance of alleles of the two investigated genes was confirmed analysing horse families. Sequencing of PCR products obtained from the MYH7 and PKM2 genes allowed to characterize two SSCP alleles for each gene. The polymorphisms found in the MYH7 and PKM2 genes were further studied in 61 and 68 horses of three (Italian Heavy Draught Horse, Italian Saddler and Murgese) and five (Franches-Montagnes, Haflinger, Italian Heavy Draught Horse, Murgese and Standardbred) breeds, respectively. Allele frequencies of the two loci varied among the considered breeds. The SNPs discovery in MYH7 and PKM2 genes allows to locate new molecular markers to ECA1. The identified markers could be used in association analysis with performance traits in horses.