The cellular ultrastructure of Asgard archaea - the ancestors of the eukaryotic cell

How did the complex, eukaryotic cell originate? The traditional view of a primitive prokaryotic (archaeal) cell, which aquired mitochondria and then evolved more complexity, has recently been challenged by the discovery of a group of uncultivated archaea (Asgard archaea) that represent the closest prokaryotic relatives of eukaryotes. Based on environmental genomics data and biochemical evidence these prokaryotes may have surprisingly complex cells. We hypothesize that Asgard archaea possess a eukaryotic-type cytoskeleton and membrane trafficking system. We will test this hypothesis by cultivation-independent microscopic ultrastructure analyses of Asgard archaeal cells. If confirmed this would dramatically change our definition of the prokaryotic cell and our understanding of the early evolution of eukaryotes.