May 27, 2011
A debate that erupted 5 months ago over whether a bacterium incorporates arsenic into its DNA is about to start simmering again. Today online in Science eight research groups voice their concerns about a paper that appeared 2 December 2010 online in Science and will be published in next week’s issue of the journal. The original article presented an exception to one of the fundamental rules of life on Earth. To survive, microbes, plants, and animals all require six essential elements: oxygen, carbon, nitrogen, hydrogen, sulfur, and phosphorus. But NASA astrobiology fellow Felisa Wolfe-Simon and her colleagues isolated a bacterium that, when grown with high arsenic concentrations and no added phosphorus, appears to replace some phosphorus with the chemically similar arsenic in key biomolecules, including DNA.