Update 11 July 2012: Following a series of critiques last May, Science has now published two papers, one by Rosie Redfield at the University of British Columbia in Vancouver, Canada, and another by Tobias Erb at ETH Zurich in Switzerland, debunking the claim that the Mono Lake bacterium can incorporate arsenic into its DNA.
Science has not withdrawn the original paper, but it has issued an editorial statement which says that "the new research clearly shows that the bacterium, GFAJ-1, cannot substitute arsenic for phosphorus to survive".
Original article, posted 27 January 2012
LIFE may not be built on a foundation of poison after all.
A year ago, Felisa Wolfe-Simon, then at NASA's Astrobiology Institute in Menlo Park, California, stirred controversy with claims that, in the lab, she had encouraged bacteria from an arsenic-rich lake in California to swap the usual phosphorus in their DNA for toxic arsenic.
Now, after trying to grow the same strain of bacteria in a soup containing arsenic, other researchers have failed to repeat the findings. "To the limit of what our spectrometer will detect, there's no arsenic in the DNA," says Rosie Redfield of the University of British Columbia in Vancouver, Canada, who posted her results to a blog this week.
Wolfe-Simon has defended her original results and is continuing to analyse her lab-grown bacteria at the Lawrence Berkeley National Laboratory. "As far as we know, all the data in our paper still stand," she told New Scientist. "We shall certainly know much more by next year."
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