Figure 4. Phylogenetic analysis COB orthologs extracted from the GOS database.

A phylogenetic tree is shown that is based on an alignment of COB protein sequences from the reference set of alphaproteobacterial and mitochondrial species supplemented with a pruned set of GOS sequences (shown in bold). The main alphaproteobacterial orders Rickettsiales, Rhodobacteriales, Rhodospirillales, Sphingomonadales, Caulobacteriales and Rhizobiales are indicated in coloured shading. Note that the SAR11 clade encompassing Ca. Pelagibacter ubique is unrelated to the mitochondrial lineage. The tentative placement of the outgroup (OG) is indicated with an arrow. Phylogenies were produced using Bayesian methods with the CAT model. Numbers at nodes denote posterior probability values. Numbers associated with GOS clades denote the number of GOS sequences here represented as a single terminal node.