When scientists ran DNA analysis on a sediment core taken from the floor of the Arctic ocean back in 2010, they found something surprising. A previously unknown organism belonging to the strange domain of microbes called Archaea appeared to have genomic characteristics associated with a totally different domain - Eukaryota. They named their discovery Lokiarchaeota, after the Loki's Castle hydrothermal vent near Greenland where it was found; but doubt shadowed the finding. Could the sample have been contaminated by something else in the core? Now, thanks to the work of Japanese scientists, those doubts can be put to rest. For...