In a press conference held at NASA's Washington D.C. headquarters, scientists announced that they had discovered a new form of bacteria, known as GFAJ-1, in California's Mono Lake that has DNA completely foreign to anything ever before found on Earth. It substitutes arsenic at the DNA level for phosphorus.
That would distinguish it from every other form of life known to man, all of which, no matter how diverse, is comprised of the same six elements, phosphorus, sulfur, carbon, hydrogen, oxygen, and nitrogen. But the bacteria found in Mono Lake--which is known for its unusual chemistry, including very high levels of salinity, alkalinity, and arsenic--is made partly of arsenic, and has no phosphorus in its DNA.
"We've discovered an organism that can substitute one element for another," said Felisa Wolfe-Simon, a NASA astrobiology research fellow at the U.S. Geological Survey in Menlo Park, Calif. "We've cracked open the door to what's possible for life elsewhere in the universe. Wolfe-Simon said that by discovering a microbe that has a new form of DNA, it forces scientists to question what they've long held as true--that all life was based on the same six components.
"The newly discovered microbe, strain GFAJ-1, is a member of a common group of bacteria, the Gammaproteobacteria," NASA wrote in a release. "In the laboratory, the researchers successfully grew microbes from the lake on a diet that was very lean on phosphorus, but included generous helpings of arsenic. When researchers removed the phosphorus and replaced it with arsenic, the microbes continued to grow. Subsequent analyses indicated that the arsenic was being used to produce the building blocks of new GFAJ-1 cells."
NASA feels that this discovery is important because it will help scientists with many areas of future research, such as the "study of Earth's evolution, organic chemistry, biogeochemical cycles, disease mitigation, and Earth system research. These findings also will open up new frontiers in microbiology and other areas of research."
By Daniel Terdiman, a staff writer at CNET News covering games, Net culture, and everything in between.