Fig 1. Distribution of model organisms in the current eukaryotic tree of life.

Model systems capable of transgenic manipulation (according to evidence in the literature) that are considered to be typical canonical models and parasites (designated as in symbol key below tree) are indicated at ends of branches, usually by genus name. The exceptions are “Trypanosome” and “Mammal,” which contain several genera that are indicated in Fig 3. Names of lineages demarked by branches are given in outside grey semicircle. Dashed branch to LECA at root of tree indicates its ambiguous position in the current tree. Only supergroups that are discussed here are highlighted. Larger formal groups are labeled at the root of their respective subtrees. LECA, last eukaryotic common ancestor.