The Relationship of GH and LEP Genes Polymorphism with the Qualitative Characteristics of Sheep Meat

DNA sequencing of Soviet Merino sheep was performed to identify single nucleotide polymorphisms (ONP) in the GH and LEP genes associated with meat quality indicators. Based on the analysis, a missense mutation C.321C>T was found in the structure of the GH gene in exon 5, leading to the replacement of arginine with glycine; in the LEP gene in exon 3, a missense mutation C.387G>T was detected, which results in the replacement of the amino acid valine with leucine. The frequency of occurrence of alleles and genotypes in the detected single polymorphisms has been established. 321C>T of the GH gene and C.387G>T of the LEP gene. The relationship between the qualitative composition of muscle tissue in sheep and their genotypic variants for both studied genes has been revealed. The muscle tissue of the heterozygous genotype according to the mutant alleles C.321T of the GH gene and C.387>T of the LEP gene contained more protein by 3.3 and 2.4 abs.%, but less moisture by 3.3 and 2.4 abs.% than in sheep of the homozygous genotype according to the wild alleles C.321C of the GH gene and C.387G of the LEP gene. Studies of the longest back muscle of Soviet Merino sheep revealed a greater number of muscle fibers in carriers of mutant alleles C.321T of the GH gene and C.387>T of the LEP gene by 4.7 and 7.6%, but a smaller diameter of the muscle fiber by 8.9 and 5.0%, compared with muscle cells of sheep homozygous for wild alleles C.321C of the GH gene and C.387G of the LEP gene. The overall assessment of the "marbling" of muscle tissue in sheep of heterozygous genotypes for the mutant alleles C.321T of the GH gene and C.387>T of the LEP gene is 2.3 and 1.5 points higher than in homozygotes for the reference alleles C.321C of the GH gene and C.387G of the LEP gene. The results obtained allow us to consider the polymorphisms C.321C>T in the GH gene and C.387G>T in the LEP gene as genetic markers for evaluating and improving the quality of sheep meat.