An unrooted phylogenetic tree of β - and γ -Proteobacteria. The edge labeled 67 is the only edge without bootstrap support of 100; the one alternative topology covers the other 33 bootstrap trials. This tree switches the branching order of Vibrio and Haemophilus from that shown in Figures 1 and 2. This tree should be more reliable, due to better taxon sampling and protein representativeness. For this less diverse set of taxa, many proteins had correlation coefficients greater than .90 with the consensus distance matrix. Notice that the two species of Vibrio are much more diverged than Escherichia and Salmonella.