New Phylogenetic Grouping of Positive-Sense RNA Viruses Is Concordant with Replication Complex Morphology

The idea that positive-sense RNA (+RNA) viruses may be to some extent taxonomically unified arose when unexpected similarities between animal and plant virus genomes were discovered (reviewed in reference 1). A comprehensive early analysis proposed three supergroups (2), which were named alpha-like, flavi-like, and picorna-like. However, the positions of several virus groups (e.g., nodaviruses, tombusviruses, nidoviruses, and leviviruses) have remained uncertain and varied in different analyses. Recent metagenomic studies have revealed additional, yet-uncharacterized virus groups and increased the amount of data (3), permitting a more powerful analysis based exclusively on RNA-dependent RNA …