Figure 4

Fraction of genes containing at least one signature peptide in genomes across the 403 bacterial reference genomes. As described in the text, signature peptides are exact matches of length 10 between genomes of different bacterial genera. The genomes are ordered along the x-axis according to their position in our bacterial phylogeny provided as Additional file 2 and Additional file 3; the ordering corresponds to that in Figure 5, starting at the 9:00 position and proceeding counter-clockwise around the radial tree.