Summary auto-generated
This study examined the phylogenetic relationships of GB viruses A and C (GBV-A and GBV-C) isolated from humans and non-human primates. Researchers analyzed complete polyprotein sequences and subgenomic regions, including the 5' non-coding region, from four GBV-A strains isolated from different New World monkey species (tamarins, marmosets, and owl monkeys) and GBV-C strains from humans and chimpanzees. Phylogenetic analysis identified eight genetically distinct GBV-A groups, each associated with a specific primate host species. The evolutionary relationships of the viruses closely paralleled those of their primate hosts, suggesting cospeciation over approximately 35 million years. The genetic distance data showed a linear correlation with primate divergence times, with virus accumulation occurring at a constant evolutionary rate of approximately 3×10⁻⁴ amino acid substitutions per site per year in both virus lineages. This pattern is consistent with cospeciation rather than cross-species transmission, similar to mechanisms documented in arenaviruses and hantaviruses. The findings support a long-term evolutionary relationship between these GB viruses and their primate hosts.
Key findings
- Phylogenetic analysis of GBV-A and GBV-C isolates revealed eight genetically distinct GBV-A groups, each corresponding to a specific New World monkey species, with clear host-virus associations.
- The evolutionary branching patterns of GBV-A and GBV-C viruses closely mirrored the phylogenetic relationships of their primate hosts, providing evidence for cospeciation over 35 million years.
- Genetic distances between virus isolates showed a linear correlation with the timing of primate species divergence events, indicating constant evolutionary rates (3×10⁻⁴ amino acid substitutions per site per year).
- Subgenomic sequences, particularly the 345-nucleotide 5' non-coding region fragment and complete E2 and NS5 genes, reliably reproduced phylogenetic relationships observed in complete polyprotein analysis.
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Abstract
GB viruses A and C (GBV-A and GBV-C) have been isolated from humans and non-human primates. Phylogenetic analysis based on full-length polyproteins suggests that these two viruses have a common ancestor. It has now been determined that analysis of subgenomic amino acid sequences in the E2 and NS5 regions of GBV-A and a 345 nucleotide segment in the 5' non-coding (5'NC) region was able to reproduce the phylogenetic relationships obtained by complete polyprotein sequences analysis. Using 5'NC sequences from databases, GBV-A isolates were discriminated into eight genetic groups, each one closely associated with specific primate hosts. Phylogenetic analyses performed on sequences from the ε-globin genes of primate hosts on one hand and complete polyprotein sequences from GBV-A and GBV-C isolates on the other suggest that a mechanism of cospeciation could be involved in virus evolution over a period of 35 million years.