Acrasids are common amoebas in the soil, where they are major predators of bacteria. Unusual for single-celled organisms, when acrasids run out of food they gather by the thousands and cooperate to form simple tree-like fruiting bodies. These greatly enhance the amoebae's ability to disperse. It also makes Acrasids the only mullticellular taxon in the vast, ancient and poorly studied eukaryotic supergroup Excavata. Recent work in our lab indicates that Excavates are the earliest major branch of eukaryotes, meaning they have an evolutionary history that is unique from nearly all well-studied eukaryotic organisms. We have completely sequenced the Acrasis kona genome, as well as RNA libraries from the four major stages of their life cycle. This is only the second genome sequence from a free-living member of Excavata, and the only sequence from a multicellular amoeba other than the distantly related dictyostelids. We are using this genome sequence to explore basic evolutionary questions such as the origin and evolution of complex cells (eukaryotes), mechanisms involved in the parallel evolution of aggregative multicellularity, and how cells communicate and recognize one another.
Selected references
Brown MW, et al. (2012) A contemporary evaluation of the acrasids. Eur J Protistol. 48:103-23.
Adl SM, et al. (2012) The eukaryotes. J Euk Micro 59:429-93.
Walker G, et al. (2011) Eukaryotic systematics: a user's guide. Parasitology. 138:1638-63.
Burger G, et al. (2013) Strikingly bacteria-like and gene-rich mitochondrial genomes throughout jakobid protists. Genome Biol Evol. 5:418-38.
Baldauf SL, et al. (2003) The deep roots of eukaryotes, Science. 300:1703-1706.