Tempting though it is to think of Archaea and eubacteria as just different sorts of bacteria, they are not close relatives at all. We eukaryotes—most of our genes, at least—are much closer to the Archaea. We may be even closer to some sorts of Archaea than others, and there have been calls to recognise only two (not three) major domains of life: the eubacteria, and everything else.
