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December 08, 2010

NASA's new arseninc life study flawed?

Just days after the announcement in a NASA press conference about arsenic-backbones in DNA for bacteria found in Mono Lake, experts in the field are disputing the results. See this Slate article.

Briefly, the article quotes other scientists who have noted problems with the methods used by the NASA scientists. For example, the fed the bacteria salt. The problem: the salt contained trace amounts of phosphorous. So maybe the bacteria found a way to extract that phosphorous more efficiently. Second, they did not test whether the DNA was indeed made of arsenic or whether the arsenic simply clung to tghe normal phosphorous-laden backbone. Finally, the use water in the DNA extraction process, which should have broken the DNA into tiny pieces. But instead, the DNA extraction showed it to be in normal phosphate-sized chunks (which are larger).

We can expect answers to these scientific concerns very soon.

This is real science in action and it is a great example of how the peer-review process can work. Even if the reviewers who accepted the published journal article did not do a thorough job (and I am no expert to make this judgement), the scientific field will put these results to the test.

Posted by christoq at December 8, 2010 10:25 AM


There will always be people who are critical of new findings, and I think it is necessary for the scientific community. Just because these scientists had promising results, does not mean that we should immediately believe them. As this article shows, all studies have some flaws and should be criticized, and tested to see if the claims are indeed correct because it is possible to have contamination, and flawed techniques that could skew the data.

Posted by: defried at December 10, 2010 08:52 PM

The answers to these scientific concerns will be something to look forward to. In my opinion, if the bacteria was fed with salts that had trace amount of phosphorus, then we can assume that the arsenic wasn't the only element that kept the bacteria alive. I am curious to know if NASA knew that the salts, used to feed the bacteria, had trace amounts on phosphorus. If they knew this but believed that it wouldn't influence the experiment, then they have good reasons for why they thought it wouldn't influence the experiment and I would like to hear those reasons if this were the case.

Posted by: kalajk at December 12, 2010 03:22 PM

I think it is especially interesting that these scientists were able to make such claim without having first conducted a similar review process to verify its credibility. Considering that they were suggesting that the evidence supported the presence of arsenic backbones in the DNA, it seems only logical that they would take the proper steps to confirm such a finding. But again, this story is, as suggested in the post, an excellent example of the benefits of peer review processes.

Posted by: devdrake at December 13, 2010 08:31 AM

I agree that the validity of this new arsenic life should have been more thoroughly examined before being publicized. With that said, I also agree that this sort of instance reinforces the importance of reviewing the results of any experiment or hypothesis with a team. I do think, however, that even though this news might not have been completely validated, it reflects today's scientists' continual interest in discovering life outside Earth. It is really awesome to know that such new and progressive experiments and research are consistently being executed.

Posted by: eswhang at December 14, 2010 01:08 AM

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