Polymorphism of A80V locus of LEP gene in Kholmogory breed cows

The aim of the study is to establish the allelic polymorphism of the A80V locus of the leptin gene (LEP) in long-lived Kholmogory cows at the breeding farm in the Arkhangelsk Region (JSC Kholmogory Breeding Farm). Objectives: to determine the frequencies of alleles and genotypes of the single nucleotide polymor-phism A80V; to identify the relationship between the polymorphism of this locus and the duration of economic use in Kholmogory cows. The study was carried out in the period from 2023 to 2024 in the laboratory of inno-vative technologies in the agro-industrial complex based the Federal State Budgetary Institution FITSKIA Ural Branch of the Russian Academy of Sciences. The object of the study was a group of long-lived cows lactating for the 4th or more lactations (n = 81). DNA extraction was carried out from whole blood in accor-dance with the brief instructions for use of the MagnoPrime VET reagent kit. The allelic variants of the A80V locus of the LEP gene were determined by the PCR-RFLP method using a pair of specific primers (F: 5’-CAAGCAGGAAATAGGGAGTCATGG-3’ and R: 5’-CTGGTGAGGATCTGTTGGTAGGTC-3’) of the PspE I restriction endonuclease. Upon completion of the statistical processing of the typing results, the dominance of the A allele (90 %) and AA genotype (80.25 %) in the gene pool of the livestock was revealed, the V allele (10 %), genotypes AV (18.52 %) and VV (1.23 %) were encountered much less frequently. According to the value of the deviation of the empirical distribution of genotype frequencies from the theoretical one (0.016), marker selection for the studied locus is not carried out in this farm, which is confirmed in practice. The high frequency of occurrence of the allele A of the A80V locus of the LEP gene in the gene pool of long-lived cows of the Kholmogory breed suggests that it is this allele that determines the genetic predisposition of these ani-mals to long-term economic use.