by Shaun Doyle

Claims of ‘new biology’ and ET life fall flat

At the end of 2010, we commented on claims that NASA scientists had found evidence of arsenic-eating bacteria that supposedly supported the idea of ET life (see NASA’s ET suffered arsenic poisoning!) and followed the controversy as it unfolded (see the two postscripts appended to the original article). The whole controversy started with a cryptic press release by NASA that said this:

“NASA will hold a news conference at 2 p.m. EST on Thursday, Dec. 2, to discuss an astrobiology finding that will impact the search for evidence of extraterrestrial life [emphasis added].”

The mere mention of ‘ET’ set the media and the blogosphere ablaze with speculation. It had some more radical commentators prognosticating that NASA was going to produce a live ET, or some other such nonsense. The find was much more prosaic than this, but was still very significant for our understanding of biology on Earth if true. Research was published in Science that announced evidence of the discovery of the first life we knew of that incorporated Arsenic (As) into its biomolecules, including its DNA.1

Arsenic is a close chemical analogue of phosphorus (P), and this research was presented as evidence that an organism was able to replace P with As in its biochemical structure. Phosphorus is essential for numerous biomolecules, including essential ones like DNA, RNA, and ATP (adenosine tri phosphate), and the substitution of such an essential and ubiquitous nutrient was completely unheard of. Arsenic is certainly not identical to phosphorus,2 and is better known as a poison.

However, upon hearing the news the blogosphere was again set abuzz. However, this time it was not by radical speculations about ET, but by numerous highly qualified scientists slamming the work as bad science. The researchers defended their work, and basically said: “The blogosphere is not the place for scientific debate—let our detractors refute us in the scientific literature.” While this was rather disingenuous given the way the news was revealed, scientists took up the challenge. Two research papers from independent teams seeking to confirm the original claims have just recently been published—again by Science.3,4 It looks like the skepticism this claim was met with was justified—the results are not pretty for the idea that these bacteria (called GFAJ-1) incorporate As into their biomolecules.

What was wrong with the original claim?

The research teams identified numerous problems with Wolfe-Simon et al.’s1 claims. One problem identified by both Reaves et al.3and Erb et al.4 was that numerous tests failed to find any detectable As in the DNA of GFAJ-1 regardless of As or P concentrations. Both studies found that no As was found in the structure of the DNA of GFAJ-1 when analysed by mass spectrometry,5 and the DNA didn’t behave in water outside of the cell as would be expected if it contained As in its structure….


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