Elsevier

Virology

Volume 255, Issue 2, 15 March 1999, Pages 294-301
Virology

Regular Article
Natural Selection of thePolGene of Bovine Immunodeficiency Virus

https://doi.org/10.1006/viro.1998.9572Get rights and content
Under an Elsevier user license
open archive

Abstract

Genetic variability is a salient feature of lentiviruses, contributing to the pathogenesis of these viruses by enabling them to persist in the host and to resist anti-retroviral treatment. Bovine immunodeficiency virus (BIV), a lentivirus of unknown pathology, infects cattle in the United States and worldwide. Genetic diversity of BIV that is associated with naturally infected cattle is not well studied. We examined the genetic diversity and natural selection of a segment of the BIVpolgene amplified from the leukocyte DNA of naturally infected cattle. A portion of the reverse transcriptase domain (183 bp) of thepolregion was targeted for amplification by PCR. PCR products were sequenced directly and aligned. When compared to the sequences of BIV R29-127, a molecular clone of the original BIV R29 isolate, all isolates were greater than 91% identical in nucleotide sequences and 77% identical in amino acid sequences.Polgenotypes were polymorphic at 14% of the nucleotide sites. The ratio of nonsynonymous to synonymous nucleotide substitutions (relative to the number of respective sites, Ka/Ks) was 0.16, indicating that this region of the BIV genome, like that of HIV-1, is subject to purifying selection. Based on the McDonald–Kreitman analysis, this region also was under positive Darwinian selection as HIV-1 and BIV diverged from a common progenitor. Phylogenetic analysis revealed that genotypes were geographically distinct, possibly indicating a common source of infection for animals within a herd.

Cited by (0)

1

To whom correspondence and reprint requests should be addressed. E-mail:[email protected].