Biological Diversity of Haplotypes of the Bovine Leukemia Virus (BLV)

Abstract

Aim. This article is devoted to the study of the molecular structure of the LTR-region of the BLV genome (bovine leukemia virus) circulating in herds of the black-and-white Holstein breed in the Novosibirsk Region.Material and Methods. Blood samples (n=288) of black-and-white Holstein cattle were taken in 2016 in the Novosibirsk Region. Screening for the pres-ence/absence of BLV was carried out by PCR analysis. Hematological studies were carried out using a hematological analyzer RSE-90 Vet.Results. BstMAI restrictase forms the same sections for all the studied samples, visualized as fragments of 237 and 206 bp in length, respectively. The hydrolysis of restrictase BspI showed the formation of fragments of 262 and 161 bp in 100% of the samples, which indicates the monomorphism of the site for nucleotide A (adenine). Hydrolysis by endonuclease Bse1 formed fragments 370 and 73 bp long, which correspond to haplotype I, as well as 378 and 65 bp, which correspond to haplotype III. The correspondence between the virus haplotype and the number of bovine leukocytes was considered but no significant differences in the leukocyte formulas of haplotype I and III carriers were found. Various hypotheses of evolutionary models of the relationship between BLV and cattle, where the determining factor might be polymorphism of the LTR virus region, are considered.Conclusion. Our own research and data in the literature indicates the invalidity of the hypothesis of the influence of mutations of 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
• agriculture