Trees calculated from amino-acid sequence alignments. (a) The YfhM group of bacterial α2-macroglobulins; (b) the PBP1Cs that always co-occur and are usually found adjacent in the same operon. As shown by the key, branches are color-coded by taxon for easy visualization of phylogenetic inconsistencies. All branches have Bayesian posterior probabilities of 1.0 (that is, are completely stable during resampling) unless otherwise indicated. Three branches not shared between the trees are indicated by dotted lines: all other branches are congruent. The roots of the trees are not known, so the time vector of deep internal branches is not clear. See Materials and methods for details of the tree calculation.