Maximum likelihood phylogeny showing global rhs genetic diversity. The ML phylogram was estimated from a multiple alignment of 81 rhs core domain nucleotide sequences from 11 genera, using a GTR+Γ model. Scale is in substitutions/site. The topology is concordant with alternative trees estimated from protein sequence alignments, and with Bayesian phylogenies. Node support is provided by non-parametric bootstrap values/Bayesian posterior probabilities; an asterisk * denotes values of 100/1.00 respectively. Each terminal node is labelled with the species (in bold), strain and locus tag, where available. Existing rhs aliases are shown in red next to E. coli K12 rhs sequences. The tree is subdivided into six clades and the phylogenetic distribution of each bacterial genus is shown on the right.