English: Roniviridae. Maximum Likelihood phylogenetic tree inferred in MEGA 7.0 (Kumar et al., 2016) from a ClustalW nucleotide sequence alignment of a 661nucleotide region of ORF1b for 21 viruses representing eight identified genotypes in the yellow head virus complex. The aligned sequence extends from within the HEL1 helicase domain (encompassing motifs V, Va and VI) and into the variable region immediately preceding the ExoN exonuclease domain. The evolutionary relationships were inferred by using the Kimura 2-parameter model of nucleotide substitution (Kimura 1980). The initial tree for the heuristic search was obtained automatically by applying Neighbour-Join and BIONJ algorithms to a matrix of pairwise distances estimated using Maximum Composite Likelihood (MCL) method (Lele and Taper 2002), and then selecting the topology with superior log likelihood value. The tree with the highest log likelihood (-3065.67) is shown. Numbers at nodes indicate bootstrap support where these are > 70%. The scale bar indicates 0.05 substitutions per site.