Fifty years ago last summer, chemist Stanley Miller demonstrated that electric sparks passing through a simulation of Earth’s early atmosphere and oceans trigger the formation of amino acids, building blocks of proteins. Another chemist, Steven Benner at the University of Florida in Gainesville, is giving this work a new spin.
Scientists have long known that ribose molecules, a key constituent of RNA, form easily in Miller’s “prebiotic soup,” but they normally break down too quickly to link together to form this simple genetic material. Benner theorized that some other ingredient might have kept ribose from degrading. “The prebiotic soup is sitting in a planet that has rocks and minerals,” Benner says. “So we asked: ‘Could any of these minerals stabilize ribose?’” Soon his team found an answer. In the presence of borax, ribose molecules can last for months (instead of hours) and accumulate in large quantities.
Borax exists most commonly in arid climes, which implies that the environment that spawned life on the ancient Earth might have been far drier than previously envisioned. “We may have to redirect our search for the origin of life from soup to desert,” Benner says.