Support for the 4th domain of life hypothesis [18] from analyses of informational genes using different models.

“Yes” denotes a “4-domains” topology sensu Boyer et al [18] in which the NCLDVs emerge as a monophyletic group branching between Archaea and Eukaryotes; in cases where we report no support, the NCLDVs emerge from within the eukaryotic domain, or the relationships among viruses and Eukaryotes are not resolved at posterior probability 0.5. (f) indicates a model mis-specification and thus failure of the respective test with regards to compositional heterogeneity, biochemical diversity, or both; (p) indicates that both tests were passed. In case of a compositional fit, no further vectors were added to the respective model, indicated by ‘n.a.’ (not analyzed). The addition of 2, 3 and 4 Dayhoff vectors led to a similar result with regards to topology, but a failure of the ChiSquare test.