Phylogenetic analyses of the GlyRS heterodimer subunits. Tree represents history of concatenated sequences of the α2 and β2 subunits of the heterotetramer form. This form is found only in the bacterial domain. Colors specify major bacterial clades, including Proteobacteria (blue), Actinobacteria (magenta) and Firmicutes (brown). More narrow taxonomic designations are bracketed and labeled. Dotted lines represent branches with <50% BS support; major clades with >80% BS support are labeled with respective BS support values. Italic numbers represent posterior probability (PP) support values from tree reconstruction in PB. For the PB reconstruction, a subset of the alignment was used, consisting of 743 well-aligned sites identified by GUIDANCE. Significant conflict between the ML and PB trees is shown by an alternative diagonal branching. The alignment contains 168 taxa with alignment length of 2028 amino acids. The tree was rooted placing Thermotogales/Aquifex as the outgroup (see methods for rooting details). Branch lengths depict substitutions/site. (*) long-branched taxa removed in the PB analysis to facilitate convergence. (**)PP support value in the alternative PB topology.