NASA Finds New Life Form

Dec 8

At its conference today, NASA scientist Felisa Wolfe-Simon will announce that NASA has found a bacteria whose DNA is completely alien to what we know today. Instead of using phosphorus, the bacteria uses arsenic. All life on Earth is made of six components: carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur. Every being, from the smallest amoeba to the largest whale, shares the same life stream. Our DNA blocks are all the same.

But not this one. This one is completely different. Discovered in poisonous Mono Lake, California, this bacteria is made of arsenic, something that was thought to be completely impossible. While Wolfe-Simon and other scientists theorized that this could be possible, this is the first discovery. The implications of this discovery are enormous to our understanding of life itself and the possibility of finding beings in other planets that don’t have to be like planet Earth.

From NASA:

Researchers conducting tests in the harsh environment of Mono Lake in California have discovered the first known microorganism on Earth able to thrive and reproduce using the toxic chemical arsenic. The microorganism substitutes arsenic for phosphorus in its cell components.

“The definition of life has just expanded,” said Ed Weiler, NASA’s associate administrator for the Science Mission Directorate at the agency’s Headquarters in Washington. “As we pursue our efforts to seek signs of life in the solar system, we have to think more broadly, more diversely and consider life as we do not know it.”

This finding of an alternative biochemistry makeup will alter biology textbooks and expand the scope of the search for life beyond Earth. The research is published in this week’s edition of Science Express.

Carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur are the six basic building blocks of all known forms of life on Earth. Phosphorus is part of the chemical backbone of DNA and RNA, the structures that carry genetic instructions for life, and is considered an essential element for all living cells.

Followup – Doubts Brew About NASA’s New Arsenic Life:

An arsenic-loving microbe found in a salty lake, which was touted last week as a potentially new form of life, is under heavy fire from the scientific community.

The microbe, a bacteria called GFAJ-1, can apparently use arsenic instead of phosphorous to build its DNA, a trick no other life form has ever managed.

A team of astrobiologists pulled the bacteria from Mono Lake in eastern California and starved it of phosphate, the molecule most organisms prefer for building their DNA backbones, while force-feeding it arsenate, the analogous form of arsenic.

The bacteria continued to grow despite the poisonous diet, prompting the researchers to assert that the microbes had successfully swapped arsenic for phosphorous. The team, led by NASA astrobiologist Felisa Wolfe-Simon, published their results in Science Dec. 2, accompanied by a very excited NASA press conference.

But other biologists started raising red flags almost immediately, questioning the methods the team used to purify the DNA and asking why the researchers skipped certain tests.

“It seems much more likely that the arsenic they’re seeing is contaminating arsenic that’s going along for the ride,” biologist Rosie Redfield of the University of British Columbia told Wired.com.

Redfield posted a biting critique Dec. 4 on her research blog. As of today, the post has received more than 40,000 hits.

She points out that the team didn’t properly clean their DNA before or after running it through a standard device for separating DNA and RNA from other molecules, a technique called gel electrophoresis.

Cleaning the samples would require “a little kit that costs $2 and takes 10 minutes, and then you have pure DNA that you can analyze,” Redfield said. The researchers used this method elsewhere in the paper, but not in the critical experiment that was supposed to show arsenic was incorporated into the bacteria’s DNA.

“That’s just asking for contamination problems,” she said. The arsenic they found could have been hanging around in the gel, not in the cells, she added. “It’s as if they wanted to find arsenic, so they didn’t take a lot of trouble to make sure they didn’t find it by mistake.”

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