Differences between our tree and the tree generated by Zhang et al. (a) In our tree, cje and hpy are grouped together because they both belong to ε-proteobacteria. (b) In the study of Zhang et al., cje and syn are clustered together, and buc and hpy are grouped into the category obligate parasites/symbionts. cje, Campylobacter jejuni subsp. jejuni NCTC 11168; hpy, Helicobacter pylori 26695; syn, Synechocystis sp. PCC 6803;.