ASSOCIATION OF SINGLE NUCLEOTIDE POLYMORPHISMS IN THE GROWTH HORMONE GENE WITH LIVE WEIGHT OF THE KALMYK BEEF CATTLE BREED

Abstract

The meat industry is an important branch of the agrifood sector. The high
competition of the modern market and growing demands of consumers are forcing producers
to provide products of better quality. The solution to the problem of increasing the level of
reproduction and increasing the yield of meat products, as well as increasing the productivity
of cattle breeding, lies in the use of modern DNA technologies. Recently, the greatest interest
has been shown in studies, which are aimed at identifying genetic polymorphism in genes associated with the formation of quantitative and qualitative parameters of meat productivity of
cattle in different breeds. As a result of the abovementioned information, the main goal of the
research was to study polymorphisms of the growth hormone (GH) gene, to determine associations with live weight of the Kalmyk beef cattle breed. The conducted molecular genetic
studies of the GH gene region made it possible to identify three single nucleotide polymorphisms in its structure in the Kalmyk cattle: c.457C>G, L127V, T172M. It was established
that GH gene polymorphisms had two alleles A and B with different frequency of occurrence.
According to the results of the distribution of allele frequencies in animals, three genotypes
AA, AB and BB were determined in three identified polymorphisms. It was established that
among the animals of the studied population, the highest frequency of occurrence was found
in heterozygous AB genotypes in the discovered c.457C>G, L127V, T172M polymorphisms
of the GH gene, which had almost equal values of 42,41 and 41%, respectively. Whereas homozygous AA and BB genotypes had a lower frequency of occurrence in the analyzed positions (26 and 25; 32 and 32; 34 and 27%, respectively). An association of genotypes of the
discovered polymorphisms in the GH gene with live weight in the studied population of beef
cattle was identified. Carriers of wild heterozygous AB and mutant homozygous BB genotypes of the L127V and T172M polymorphisms of the GH gene were characterized by a higher live weight compared to animal individuals of the “wild” homozygous AA genotype by
9,1, 14,2 and 14,0, 23,3%.