Only organisms that make pseudopods retain both WASP and SCAR genes. Diagram showing the relationships of extant eukaryotes (based on a study by Fritz-Laylin et al., 2010) with the presence or absence of SCAR (blue) and WASP (green) genes from complete genome sequences as described previously (Kollmar et al., 2012). Each representative organism whose genome was used for the analysis is listed to the right. For groups with similar morphological and sequence patterns, a single species is used. For example, there is no known plant species that forms pseudopods or retains the WASP gene, so only a single species is shown (Arabidopsis thaliana); similarly, Aspergillus nidulans represents all dikarya. See Kollmar et al. (2012) for additional sequence information. An amoeba glyph indicates organisms that build pseudopods. Outlined rectangles indicate a lack of an identifiable gene. See Table 1 for citations and full species names. *, Although we were not able to find a reference to pseudopod formation in A. macrogynus, a relative (C. anguillulae) does assemble pseudopods used for motility (Deacon and Saxena, 1997; Gleason and Lilje, 2009). Because of this and the conservation of both WASP and SCAR in Bd (highlighted in bold), we correctly predicted this species is also capable of pseudopod formation. ⁺⁺, These species form pseudopods for feeding rather than motility. The question mark indicates uncertainty regarding the structure of the protrusions for phagocytosis in E. histolytica (see the Evolutionary retention of both WASP and SCAR correlates with pseudopod formation section). The time of divergence of extant eukaryotic groups has been estimated to be 1.1–2.3 billion years ago (bya; Chernikova et al., 2011; Parfrey et al., 2011; Knoll, 2014) and has been predicted to have possessed both WASP and SCAR gene families (Kollmar et al., 2012) and therefore may have built pseudopods.