Okay, so it isn’t life on Saturn’s moon of Titan, as some had speculated. But this discovery is garnering some gigantic type headlines. Just before today’s 2 p.m. press conference, word leaked out on various news sites that NASA-funded researchers have discovered a new, radically different life form right here on Earth–strain GFAJ-1, a bizarre bacterium from an arsenic-laden California lake that is capable of consuming and utilizing the poisonous substance in place of phosphorus, long viewed as one of the conventional chemical building blocks of life.
Here’s the just-posted NASA press release that lays out the basic facts.
Felisa Wolfe-Simon, leader of the research team at NASA’s Astrobiology Institute, explained at the press conference that the discovery revealed “a microbe doing something different from life as we knew it.” While the find will compel scientists to rewrite biology textbooks, it has far greater significance, because it provides evidence of how life forms could function differently elsewhere in the cosmos.
“We’ve cracked open to door to what’s possible for life elsewhere in the universe,” Wolfe-Simon proclaimed.
The New York Times reported just before the press conference that Wolfe-Simon and her colleagues scraped the bizarre bacterium from the bottom of Mono Lake in California and grew it for months in a lab, in a mixture that contained arsenic but no phosphorus. The microbe proceeded to gradually swap out atoms of phosphorous in its body for atoms of arsenic.
“Nothing should have grown,” Wolfe-Simon explained. Instead, researchers found that the bacterium not only ingested arsenic without dying, but that the chemical was associated inside it with a specific band of genomic DNA.
The arsenic “wasn’t just stuck,” Wolfe-Simon explained. “…it was behaving like phosphorous.”
The discovery was unsettling, because phosphorus, which life forms on earth use to build nucleic acids, has long been considered one of six essential chemicals necessary for life. (The others are carbon, hydrogen, nitrogen, oxygen, and sulfur.) In contrast, arsenic, though chemically similar to phosphorus, is poisonous to most Earth life because that similarity causes it to block metabolic pathways.
While the discovery doesn’t quite prove the existence of extraterrestrial life, Wolfe-Simon and other scientists believe that it raises the prospects that life may exist in environments previously considered inhospitable to living things.