Relative Refutation of the Claim of Arsenic-Based Life

arsenic-based-life

A controversial study from 2010 was relatively refuted by a group of scientists, trying to duplicate the findings that were published in Science. Researchers have been unsuccessful to reproduce the results from the study authored by Wolfe-Simon et al.

The team was led by microbiologist Rosie Redfield from the University of British Columbia in Vancouver and they’ve posted data on Redfield’s blog. Redfield says that she presents a clear refutation of some of the key findings from the original paper. The most striking claim was that arsenic had been incorporated into the backbone of the DNA, and there has been no arsenic in the DNA of our cells at all, she states.

graph-gfaj-1-growthThe authors aren’t retreating from their conclusions and are waiting to see if Redfield’s refutations will be published in a peer-reviewed journal. The bacterium in question, GFAJ-1, was found to use arsenic instead of phosphorous in molecules essential to life. This was a surprising finding, as phosphorous has been thought essential to life as we know it, while arsenic is considered toxic.

Redfield isn’t the only one who has raised concerns about these findings. It’s unclear how much phosphorous was used to grow bacteria in the original paper, and at which concentrations they were able to find their results since apparently the Wolfe-Simon et al records aren’t detailed enough.

Other researchers have said that Redfield and her colleagues have produced a reasonable refutation, but it will be difficult to definitely prove the complete absence of arsenic from GFAJ-1 DNA. It does not look encouraging for the arsenic-in-DNA hypothesis, states Ronald Oremland at the US Geographical Survey in Menlo Park, California.

Redfield hopes to submit her findings to Science by the end of the month. Wolfe-Simon is still looking for arsenic in the bacterium. She states that with added effort from the scientific community, a lot more will be known by next year.

[via Nature]

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