New science: ancient eukaryotes and altruistic ants.
Eukaryotes may be way older than we think. A paper in this week’sNature (with Roger Buick’s News and Views summary here) reports the finding of eukaryote-like microfossils in South American rocks dated at 3.2 billion years b.p. (before the present). Yes, that’s right: 3.2 billion. Up to now, the oldest known fossils of eukaryotic cells (i.e., “true” cells with chromosomes and a nucleus) dated 1.8 billion years b.p., so it was assumed that it took a long time to evolve the eukaryotic cell from the bacterial cell (bacterial microfossils first appear about 3.5 billion years ago). This new finding, if true, pushes back the origin of true cells very close to the origin of prokaryotic cells themselves, so it may not have been that difficult to evolve a true cell.