Phylogenetic analysis of GB viruses A and C: evidence for cospeciation between virus isolates and their primate hosts

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.