Figure 1.

Phylogeny of the Archaea whose genomes have been analyzed in this study. This unrooted tree (kindly provided by Céline Brochier) is based on the concatenation of archaeal ribosomal proteins (see [73] for details). The parasitic archaeon N. equitans is placed with Euryarchaeota in accordance with the hypothesis that it likely represents a fast-evolving euryarchaeal lineage [34].