LysRS1 gene tree. Maximum likelihood phylogenetic tree for 17 archaeal and 17 bacterial LysRS1 sequences, colored black and green, respectively. The tree has been rooted using four GluRS sequences (B. aphidicoda, E. coli, C. jejuni, T. maritima). Bootstrap percentage values greater than 50% are indicated. Arrows indicate plausible paths for LGT events. Treponema refers to Treponema denticola and Treponema pallidum. The species included in the groups alpha-proteobacteria (11), Archaea (11) are provided as SM, additional file 2. Listing of the archaeal and bacterial phyla, classes and species, with corresponding LysRS1 accession numbers and their sources are also provided in additional file 2. The complete (unabbreviated) LysRS1 ML tree is given as SM, additional file 4.