Hierarchical classification of 393 6-letter word signatures. The signatures of a given species have the same color code. For each species group, the name of the species is indicated at left. The EF-Tu gene that also forms a stable group is also highlighted. Finally, arrows point out the horizontal transfer (HT) candidates that are discussed in this article.
Chapus et al. BMC Evolutionary Biology 2005 5:63 doi:10.1186/1471-2148-5-63