The distribution of Dcd1, Dcd2, and ThyX among 19 major eukaryotic groups. The simplified tree was derived from 4 studies of the phylogeny of eukaryotes (Brown et al. 2018; Burki et al. 2020; Schön et al. 2021; Strassert et al. 2021). A solid black rectangle means that the predicted protein is present in multiple (but not necessarily all) species in the same major eukaryotic group that form a monophyletic clade in their protein phylogeny (supplementary fig. S6, Supplementary Material online). A gray rectangle means either there is only a single species in the major group that contains the predicted protein or the presence of species belonging to the same major eukaryotic group that do not form a monophyletic clade. The detailed species distribution of Dcd1, Dcd2, and ThyX in the eukaryotic clades of their respective protein phylogenies is shown in supplementary fig. S6, Supplementary Material online.