Maximum likelihood phylogenies (1,000 bootstrap replicates) of polymerase genes sequences of A. dicistroviruses (~2700 bp), B. nodaviruses (~2000 bp), C. tombus-like viruses (~1200 bp), and D. hepadnaviruses (~570 bp). Maximum likelihood phylogenetic analyses were performed with codon-based alignments of polymerase genes, with poorly aligned regions removed (see text for full description).