Figure 1

Bayesian inference tree of aSelB and aSelBL from 311 aligned amino acid positions. Bayesian inference posterior probability (BIPP) and maximum likelihood bootstrap percentage (MLBP) support are indicated on branches. Only branches with >.70 BIPP support are labelled with BIPP and MLPP values. The scale bar below the tree shows the evolutionary distance expressed as substitutions per site. The SDSF at the end of the MrBayes run was 0.005. Numbers in taxon names are NCBI GI numbers, and underlined names indicate those taxa included in the illustrative alignment (Figure 2). Archaea labelled ARMAN are those from the clade of "Archaeal Richmond Mine Acidophilic Nanoorganisms" [18]. Symbols following taxa names indicate aSelB/aSelBLs with conserved genomic context (Additional file 3). The key for genomic context symbols is in the inset box, showing the location of genes in relation to aSelBL or SelB. Gene names are abbreviated as follows: MVK, mevalonate kinase family protein; RNase P, Ribonuclease P; TatD, TatD-related deoxyribonuclease; RNase Z, Ribonuclease Z/Lactamase B family protein; hemH, Protoheme ferrolyase (ferrochelatase); alaRS, alanyl-tRNA synthetase; metRS, methionyl-tRNA synthetase.