FIGURE 1.

A maximum likelihood phylogeny of AspRS sequences from all domains of life. The eukaryotic portion is shown in greater detail to show eight independent duplication events (at nodes marked by green circles) and other relationships described throughout. Species names colored purple highlight the eukaryotes that lack a bacterial type mitochondrial AspRS. Bootstrap proportions show statistical support for major branches and for those groups referred to under “Discussion.” A fully detailed tree, including all bootstrap values and species names, is displayed in supplemental Fig. 1.