Divergence and recombination of clinical herpes simplex virus type 2 isolates.

• Herpes simplex virus type 2 (HSV-2) infects the genital mucosa and is one of the most common sexually transmitted viruses. Here we sequenced a segment comprising 3.5% of the HSV-2 genome, including genes coding for glycoproteins G, I, and E, from 27 clinical isolates from Tanzania, 10 isolates from Norway, and 10 isolates from Sweden. The sequence variation was low compared to that described for clinical HSV-1 isolates, with an overall similarity of 99.6% between the two most distant HSV-2 isolates. Phylogenetic analysis revealed a divergence into at least two genogroups arbitrarily designated A and B, supported by high bootstrap values and evolutionarily separated at the root. Genogroup A contained isolates collected in Tanzania, and genogroup B contained isolates collected in Tanzania and Scandinavia, implying that the genetic variability of HSV-2 is higher in Tanzania than in Scandinavia. Recombination network analysis and bootscan analysis revealed a complex pattern of phylogenetically conflicting informative sites in the sequence alignments. These signals were present in synonymous and nonsynonymous sites in all three genes and were not accumulated in specific regions, observations arguing against positive selection. Since the PHI test applied solely to synonymous sites revealed a high statistical probability of recombination, we suggest as a novel finding that homologous recombination is, as reported earlier for HSV-1 and varicella-zoster virus, a prominent feature in the evolution of HSV-2.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Mikrobiologi inom det medicinska området (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Microbiology in the medical area (hsv//eng)

Nyckelord

Cluster Analysis

DNA

Viral

chemistry

genetics

Evolution

Molecular

Genotype

Geography

Herpes Genitalis

virology

Herpesvirus 2

Human

classification

genetics

isolation & purification

Humans

Molecular Sequence Data

Norway

Phylogeny

Polymorphism

Genetic

Recombination

Genetic

Sequence Analysis

DNA

Sequence Homology

Amino Acid

Sweden

Tanzania

Viral Envelope Proteins

genetics

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