Amoebozoa

The Amoebozoa are a large group of eukaryotes originally thought to present basal eukaryote features and to be a basal branch at the eukaryotic tree. In fact, they are sister to the Obazoa, which together with some protozoan lineages also comprise animals and fungi. This explains the presence and conservation of some genes and signalling pathways between Amoebozoa and animals. Several clades of Amoebozoa have developed aggregative multicellularity where several to many amoebas come together to form a fruiting body. Furthermore, cell differentiation by sporocarp formation is also widespread amongst different groups of Amoebozoa. Typical for almost all Amoebozoa is the amoeboid cell movement displayed at least at some stages of their sometimes complex life cycles. They display typical eukaryotic features, like a nucleus, mitochondria, endoplasmic reticulum and Golgi-apparatus, phagocytosis, one or two flagellae of the 9×2+2 type, a cytoskeleton with actin and myosin and sexual recombination processes, even though some of those features have been secondarily lost in some groups. Amoebozoa inhabit a wide range of environments and are important grazers of bacteria in soil and freshwater communities. A few genera, like Acanthamoeba, Balamuthia and Entamoeba contain opportunistic or obligate human pathogens. The current view on classification of the group is explained and illustrated with some examples for each group. This review focuses on the changes in amoebozoan systematics recent multi-protein phylogenies have brought about. However, the availability of an increasing number of Amoebozoan genome sequences and discovery of new species might again challenge the currently held view