FIG 5.

Schematic representation of the phylogenetic tree of the RNA-directed RNA polymerases (RdRps) of RNA viruses (realm Riboviria). The five major branches discussed in the text are labeled. Only selected clades including the best-characterized virus groups are shown within each major branch. Each branch represents collapsed sequences of the respective set of RdRps. The reverse transcriptase sequences from group II introns and non-LTR retrotransposons were used as the outgroup to root the tree. The three BCs included in the tree are color-coded (orange, BC III; blue, BC IV; purple, BC V). (Adapted from reference 82.)