Evaluation of allelic frequencies distribution of the BoLA-DRB3 gene polymorphisms within exon 2 using PCR-RFLP

Abstract

BoLA-DRB3 is part of the major histocompatibility complex, which has more than 100 polymorphic sites in exon 2. This gene is associated with immunological traits, resistance or susceptibility to various diseases and productive traits and milk quality in cattle. The aim of our paper was to conduct a primary assessment of the allelic polymorphism of exon 2 of the BoLA-DRB3 gene in the Ural region using nested PCR and PCR-RFLP. The object of research were Holstein cattle (n=55). Restriction fragment lengths were determined using electrophoresis in an agarose gel. For the BoLA-DRB3.2 gene the most common genotypes were identi ed: *23/*24, *24/*24, *16/*16, *24/*28, *9/*38 with a prevalence from 8.9 % to 26.5 %; genotypes with a lower distribution frequency - *24/*38, *24/*9, *2/*37, *16/*26. In studied samples the majority of identified alleles (*2, *9, *26, *37, *38) were previously proven to be neutral. The results of genotyping of Holstein cattle according to the polymorphism of the BoLA-DRB3.2 gene were obtained: in the studied population, 56 % of individuals had a genotype associated with susceptibility to the leukemia virus, 29 % associated with resistance and 15 % had neutral genotype. Based on the obtained results, it can be concluded that there is a need for genetic screening of cattle populations for the BoLA-DRB3 polymorphism, especially in epidemiologically disadvantaged regions for the incidence of leukemia. The obtained data on the genotypes of animals will be used in breeding programs to saturate herds of farm animals with alleles of resistance to the bovine leukemia virus.