Rosie Redfield : Critical Enquirer:

Life is mostly composed of the elements carbon, hydrogen, nitrogen, oxygen, sulfur, and phosphorus. Although these six elements make up nucleic acids, proteins, and lipids and thus the bulk of living matter, it is theoretically possible that some other elements in the periodic table could serve the same functions. Phosporous is an integral part of DNA structure. If you remove Phosporous from a living organism there will be no DNA and so no life.In 2010, a group from California claimed to have found bacteria that could incorporate arsenic into their DNA in place of phosphorus (Felisa Wolfe-Simon, Science, 2010). If true, the finding showed that life could be supported by a form of biochemistry radically different from the one we know.

This year Rosie Redfield, a Canadian microbiologist wanted to take up this question again and she started putting her results everyday on her blog. But Redfield’s blog entry on the paper pulled no punches. “Basically, it doesn’t present ANY convincing evidence that arsenic has been incorporated into DNA,” she wrote. Redfield kicked off a frenzy of criticism of the ‘arsenic-life’ paper in the blogosphere and the media. In June, Science published eight critiques of the paper. The result has been a fascinating story of open science unfolding over the year. Redfield’s blog has become a virtual lab meeting, in which scientists from around the world help to troubleshoot her attempts to grow and study the GFAJ-1 bacteria — the strain isolated by Felisa Wolfe-Simon, lead author of the Science paper. For months, Redfield could not get the GFAJ-1 bacteria to grow reproducibly on a medium containing arsenic. Finally, in November, the bacteria took off. Redfield now plans to check whether they have incorporated arsenic into their DNA, but it will take even more work to show that they can survive without any phosphorus.

I just checked her blog this morning. She is still waiting for the DNA analysis results. If these bacteria have indeed replaced phosphorous with arsenic, we will witness another revolution in the field of biochemistry. Probably, bigger than the one, which happened after the discovery of structure of DNA by Watson and Crick during the 1950s.

"கற்றது கை மண் அளவு - கல்லாதது உலகளவு"
· · · December 26, 2011 near Singapore, Singapore

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