A collaborative research team led by Hiroyuki Imachi and Masaru K. Nobu of the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) and Satoshi Nakagawa of Kyoto University has for the first time isolated and cultivated two strains of Heimdallarchaeia, a group of archaea that are among the closest known archaeal relatives of eukaryotes—the organisms that include humans and other animals, as well as plants and fungi.