Polymorphism of Haplotypes of Bovine Leukemia Virus

Abstract

The study of molecular structure in LTR regions of the BLV genome (bovine leukemia virus), which is present in the holsteinized Black Pied breed in the Novosibirsk Region, with the subsequent differentiation into haplotypes. Screening for the presence / absence of BLV was performed by PCR analysis. Hematological studies were performed using a PCE-90 Vet hematology analyzer. The affiliation of the virus to haplotypes was determined by several specific sites using a set of three endonucleases. Hydrolysis with BstMA I endonuclease showed the presence of fragments 237 bp long and 206 bp long in all the studied samples. Restriction of BspI in 100% of the samples revealed the presence of fragments 262 and 161 bp, which indicates the monomorphism of the site for nucleotide A (adenine). Fragments of 370 and 73 bp, which corresponded to haplotype I, as well as 378 and 65 bp, which were interpreted as haplotype III, were obtained from Bse1 restriction results. The fact of presence / absence of the dependence of the number of leukocytes on the haplotype of the virus is analyzed. The results showed the absence of significant hematological differences in blood samples of carriers of I and III haplotype. Various hypotheses of evolutionary models of the relationship between BLV and cattle are considered, where the LTR polymorphism of the virus region could be a determining factor. The totality of our own research and literature data indicates the failure of the hypothesis about the effect of mutations in the LRT region on the degree of recognition of BLV by the immune system of cattle. Keywords-SNP, bovine leukemia virus (BLV), LTR region, restriction fragment length polymorphism, leukemia, haplotype.The work is performed on the means of Finance on the instructions of the Ministry of agriculture of Russian Federation (№ АААА-А18-118101190004-2).