Evolution of the WASP family proteins with respect to the species evolution. Schematic representation of the most widely accepted eukaryotic tree of life. Branch lengths are arbitrary. The WASP family protein inventories of certain taxa and specific species have been plotted to the tree with WASP subfamilies given in colour-coded boxes. White boxes in certain lineages or species indicate the loss of the ARP2/3 complex. Blastocystis hominis contains the ARP2/3 complex and is thus expected to contain an activator protein although none of the WASP family members could be identified. The numbers on the arrows refer to alternative placing of the respective taxa: 1: The monophyly of the Diplomonadida (instead of grouping them to the superkingdom Excavata) is supported by . 2: The monophyly of the Rhodophyta is supported by [45, 48]. 3: Grouping the Haptophyceae to the Chromalveolata is supported by [45–47].