Figure 2. Phylogenetic Distribution of the NHEJ Ku Protein in Bacteria.

A diagrammatic tree representation of major phyla, classes, and families of bacteria, as indicated by the relevant names is shown. Lines between the names illustrate well-established phylogenetic links within the various phyla. Stars in green indicate phyla that contain homologues of Ku. Numbers in green indicate the number of species with completed genome sequences that are within each phylum and contain one (or more) homologue(s) of Ku. Stars in blue indicate classes/orders that contain homologues of Ku. Numbers in blue indicate the number of species with completed genome sequences that are within each class that contain one (or more) homologue(s) of Ku. Stars in red indicate families that contain homologues of Ku. Note that there is no instance in which a Ku homologue is contained in all species within a phylum/class.