Figure 1.

A phylogenetic tree depicting all nodes (branchpoints) on the evolutionary line leading to humans. The species groupings (clades) given here along the top are those used in [8]. The 'basal eukaryotes' are a diverse polyphyletic group (not a single clade) of mainly unicellular organisms such as excavates and chromalveolates, and this grouping is thus labelled 'uncertain'. The nodes studied by Huerta-Cepas et al. [3] are indicated by the black bars. The clades in which at least one complete genome sequence is available are marked with an asterisk. All eukaryotic clades with a genome sequence were included in the phylogenetic analysis of Huerta-Cepas et al., except for the Ambulacraria, for which a genome sequence (of the echinoderm Strongylocentrotus purpuratus) has only recently become available.