Extended Data Figure 4. Phylogenetic tree of bacterial tae4 and eukaryotic dae4 genes.

Phylogenetic trees were constructed using either maximum likelihood methods (a) or Bayesian methods (b). Branch support > 0.7 is indicated by asterisks or by numbers. The scale bar shows estimated divergence in amino acid changes per residue. Eukaryotic dae4 genes are indicated by dashed boxes, which highlight two separate HGT events. In both trees, the two eukaryotic dae4 clades are well supported as monophyletic clades, supporting our conclusion of two separate HGT events. Likewise, many major bacterial groups are well supported in both trees. Differences in the overall topology of the trees, mostly owing to changes in deep branches that are not well supported in either phylogenetic tree, reflect uncertainty in the ancient history of these genes and should therefore be treated with caution.