Figure 4. A species tree of alphaproteobacteria and mitochondria.

The Bayesian consensus tree was based on concatenated protein sequences of 55 mitochondrial and nuclear genes. The tree was rooted using 8 beta- and gammaproteobacteria as the outgroup, as described in the methods. Asterisks indicate 5 newly sequenced Rickettsiales species. The posterior probability support values of the internal nodes are greater than 0.9 unless as indicated in the tree. Branches of several lineages are shortened for display purpose. The distribution of ATP/ADP translocase, flagella genes, cbb3 cytochrome oxidase and bd-quinol cytochrome oxidase in Rickettsiales and mitochondria is displayed besides the lineages.