NASA Research Points to Possible Path for Alien Life

(Wall Street Journal) - Pushing life to extremes, researchers reported Thursday that they have discovered microbes able to subsist almost entirely on arsenic, which "very likely" incorporate it into their DNA, the Wall Street Journal reported.

The finding may be the first exception to the formula long thought to govern the basic chemistry of life.

Force-grown in the laboratory, these bacteria use the notorious poison to replace molecules of the element phosphorus in critical parts of their working biology, including in the spiral backbone of DNA, which is a crucial component for all known life, the researchers said. By depending on an element so toxic to normal life, the microbes are a living demonstration of the exotic substances that alien biochemistry might, in theory at least, use on other worlds.

"It is building itself out of arsenic," said geo-microbiologist Felisa Wolfe-Simon at NASA's Astrobiology Institute and the U.S. Geological Survey, who led researchers from eight federal and university laboratories conducting the experiment. "All life we know is the same biochemically, and this is a little different. It is suggesting there is another way to be alive."

The researchers conceded, however, that by themselves these odd microbes don't prove yet that there is a fundamentally different basis for life on Earth. "It is beginning to open the door a crack to possibilities," she said.

Until now, all microbes thought to share a biochemistry based on the same six elements—oxygen, hydrogen, nitrogen, sulfur, carbon and phosphorus—to build proteins, fats and DNA. Even the synthetic cells made in the laboratory, as announced earlier this year, rely on the same six elements. Phosphate is an essential building block for various macromolecules present in all cells, including nucleic acids, lipids and proteins.

Their finding comes as the hunt for Earth-like planets accelerates. With 22 space-based observatories and 100 ground telescopes, researchers are scanning tens of thousands of stars for evidence of a planet that could support life like that on Earth.

Read more: Wall Street Journal