In the TV series Star Trek, the Borg are cybernetic aliens that assimilate humans and other creatures as a means of achieving perfection. So when Jill Banfield, a geomicrobiologist at the University of California, Berkeley, sifted through DNA in the mud of her backyard and discovered a strange linear chromosome that included genes from a variety of microbes, her Trekkie son proposed naming it after the sci-fi aliens. The new type of genetic material was a mystery. Maybe it was part of a viral genome. Maybe it was a strange bacterium. Or maybe it was just an independent piece of DNA existing outside of cells. Whatever it is, it’s “pretty exciting,” says W. Ford Doolittle, an evolutionary biologist at Dalhousie University who was not involved with the work.