Dictyostelium, the Social Amoeba

The Dictyostelia present a splendid opportunity for the study of mutualism, sociality and genetic conflicts of interest. These amoebae aggregate upon starvation to form cooperative multicellular structures in which some formerly independent cells die to form a stalk. This serves to lift the other cells above the substrate where their chances of dispersal are greatly enhanced, for example by sticking to passing invertebrates. Dictyostelia vary in their social organization and the cells can be cultured from soil samples from nearly all parts of the world. Furthermore, they have complex symbiotic interactions with bacteria. Together these make many kinds of studies possible. Genome sequences are also available for increasing numbers of species; many molecular pathways are known; and experimental evolution is feasible. Who lives, who dies, and how sociality and mutualism are structured are great questions that are easily addressed in this group.