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NASA Scientists Find Unusual DNA Form of Arsenic

Image of GFAJ-1 grown on arsenic
Image of GFAJ-1 grown on arsenic

NASA scientists on Thursday announced they have found a new source of bacteria, made of something earlier thought impossible. The bacteria's DNA is not made of phosphorus but of arsenic. The scientific community can barely contain themselves about the findings. Within two hours of the announcement, more than 2,000 articles about it were found on the internet. Our correspondent explains how this could change what we know about life and the possibility of life outside of earth.

The picture NASA shows us looks like a bunch of white fingerling potatoes. But we are told, these microbes change everything. Here's NASA's director of Astrobiology, Mary Voytek.

"This is a huge deal," she said. "It's going to require at least some paragraphs in a textbook to be rewritten, perhaps. This is a big finding."

The real star of the NASA briefing is named GFAJ 1. It's a microbe that thrives on arsenic, an element that is normally poisonous. NASA's Felisa Wolfe-Simon discovered the bacterium with a team from Arizona State University.

"All life that we know of requires carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur," said Wolfe-Simon. "And it uses those six elements in critical pieces that I think we are all familiar with, including DNA and RNA. We've discovered an organism that can substitute one element for another in these major biomolecules."

The researchers found the bacteria in Mono Lake, a Northern California lake that has three times the salt of sea water and is full of arsenic. The team scraped the bacteria from the bottom of the lake, then grew it in a laboratory, where it incorporated arsenic - rather than phosphorus, which was previously thought to be the backbone of DNA and RNA. Wolfe-Simon says extra terrestial life could be possible.

"I was taught as a biochemist all life we know of is here so far, and if there's an organism doing something different, we've cracked open the door to what's possible for life elsewhere in the universe," she said.

But chemist Steven Benner, from the Foundation for Applied Molecular Evolution is cautious. He says arsenic molecules would be a weak link in a compound under stress.

"We know they are relatively unstable and they fall apart with half lives measured in the order of minutes, conveniently," said Benner. "When you try and put them into a DNA molecule, and you put them under stress they fall apart."

Wolfe-Simon points out that for every one of a human's cells, there are ten microbial cells. Therefore, she says this finding has implications in how our bodies work, in addition to how the planet works.

Meantime, this announcement dealt with a scientific discovery. Others will announce the practical implications of it -starting with the tiny GFAJ 1 and its fellow potato-looking microbes.