Embarking on what one scientist likens to "the 21st-century equivalent of Lewis and Clark’s expedition to open the American West," an international team of researchers is undertaking an unprecedented examination of microbial "dark matter" in hopes of understanding the microbial evolution of the planet.
"This is really the next great frontier," Eddy Rubin, director of the U.S. Department of Energy Joint Genome Institute, said in a news release.
The team’s most recent findings were published July 21 in the online version of the journal Nature. The effort, led by the DOE JGI, involves DNA sequencing of genomes isolated from single cells. The scientists are using uncultivated microbial cells from nine diverse habitats — including the ocean north of Oahu.
Material has also been drawn from Sakinaw Lake in British Columbia; Etoliko Lagoon in western Greece; a sludge reactor in Mexico; the Gulf of Maine; the tropical gyre in the South Atlantic; the East Pacific Rise; the Homestake Mine in South Dakota; and the Great Boiling Spring in Nevada.
Scientists laser-sorted 9,000 cells, from which 201 genomes were reassembled and identified. These genomes were then aligned to 28 previously uncharted branches of the tree of life for single-celled organisms.
"Microbes are the most abundant and diverse forms of life on Earth," said Tanja Woyke, the institute’s microbial program head and senior author of the Nature article. "They occupy every conceivable environmental niche, from the extreme depths of the oceans to the driest of deserts. However, our knowledge about their habits and potential benefits has been hindered by the fact that the vast majority of these have not yet been cultivated in the laboratory.
"So we have only recently become aware of their roles in various ecosystems through cultivation-independent methods," she said. "What we are now discovering are unexpected metabolic features that extend our understanding of biology and challenge established boundaries between the domains of life."
The institute is in Walnut Creek, Calif.
