It has been suggested that all magnetotactic systems are descended from a single monophyletic origin. Examples of organisms that either produce the mineral magnetite (Fe3O4) and/or are magnetotactic have been described for two of the three primary phylogenetic domains, the eubacteria and the eukaryotes, but not for the third, the archaebacteria. In order to fill this gap, we have begun a search for magnetotactic archaebacteria.
Since archaebacteria tend to inhabit extreme environments, we began our search at Mono Lake, which is known to be pH 10-11 and to have about three times the salinity of sea water. Samples were obtained from several parts of the lake and subjected to a one-hour magnetic extraction. Material that collected at the magnet was frozen for future examination. In addition, samples of mud and water were also collected. PCR was then performed on DNA extracted from the samples, using primers specific for archaebacterial 16S ribosomal RNA, and the products were cloned and sequenced. Samples from mud and water yielded sequences with extremely high similarity to unidentified marine archaeons and to a number of methanogens, thereby establishing the presence of archaebacteria in Mono Lake. PCR products were also obtained from the magnetotactic material and are currently being processed.