Figure 6

A speculative scenario of the evolutionary history of the DUS family. This scenario is based on the assumption that Bacteria, Archaea, and Eukaryota are all monophyletic, that Archaea and Eukaryota are sister lineages, and that the root (corresponding to the LUCA) is located in the branch between Bacteria and the Last Archaeal and Eukaryotic Common Ancestor (LAECA). Three major branches correspond to the three Domains of Life. Each DUS subfamily is represented by a single line of a particular color (e.g. DusB in magenta, DusA in cyan). Bifurcations represent duplications (giving rise to paralogous families), and horizontal lines represent horizontal gene transfers.