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Ah, me, it would have been so exciting if correct
Remember the story about bacteria being found that incorporated arsenic into their DNA?


It all sounded so exciting. What's more, the scientists were from NASA and the paper (Wolfe-Simon F, Blum JS, Kulp TR, Gordon GW, Hoeft SE, Pett-Ridge J, Stolz JF, Webb SM, Weber PK, Davies PC, Anbar AD, & Oremland RS (2010). A Bacterium That Can Grow by Using Arsenic Instead of Phosphorus) was peer-reviewed and published in Science.

It didn't take long for other life-scientists to take a good, hard look at the paper and, as could almost be predicted from the last time NASA publicity machine made such an astonishing statement (the bacteria from Mars), the reviews are not looking good. The critique to which other scientists in the field seem to be referring is this one from Professor Rosie Redfield at the University of British Columbia.

It is, as might be expected, somewhat technical - though by no means totally unintelligible even to a non-scientist like me - and the comments are worth reading for the support arriving from other microbiologists.

To us not-lab-microbiologist types, the key paragraphs are these.

"Bottom line: Lots of flim-flam, but very little reliable information. The mass spec measurements may be very well done (I lack expertise here), but their value is severely compromised by the poor quality of the inputs. If this data was presented by a PhD student at their committee meeting, I'd send them back to the bench to do more cleanup and controls.

There's a difference between controls done to genuinely test your hypothesis and those done when you just want to show that your hypothesis is true. The authors have done some of the latter, but not the former."

Though, as yet, the matter of the arsenic-DNA bacteria is still open, I'm afraid we are going to have to wait a while for real proof, one way or the other.

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Thanks for catching this. There will undoubtedly be more peer reviews, shedding more light one way or the other on the quality of the work.

The first reports were so over-the-top that I was waiting for the other shoe to drop -- and it did. My money is always on "bad analysis of data" over "astounding new discovery." lol

Even worse, the paper did not actually claim to have proved what the NASA publicity machine said it did.

Much of what is said about the lake involved is wrong, too. It is full of life, so much so that it is a major stop-over for migratory birds.

That's what I get for not reading the original data. lol

NASA has become a brothel for publicity whores.

I shall keep an open mind until more data is collected.

Human nature being what it is, the backlash was inevitable, valid or not.

the matter of the arsenic-DNA bacteria is still open

But, in fact, the publicity from NASA as reported in the Press - who were unable to check with real scientists because the story was under embargo - was nothing like the actual claims of the paper.

Those were, in fact, that bacteria which were quite normal genetically, could be forced to take up arsenic in the absence of phosphorous and incorporate same as a substitute into their DNA during growth and reproduction. However, the claims from elsewhere are not that the claims may not be true but, using the data supplied in the paper itself, that the experiments were flawed because of contamination.

Edited at 2010-12-07 06:54 pm (UTC)

When dealing with a local phenomenon like that, with such a well-understood and defined transaction, I think the chances of any deviation from the norm to be minimal. We're not talking about some unknown wow factor but a well-known and well-understood specific thing. It's not Saul becoming Paul but Saul turning into a reptile. lol

Thanks. Until you mentioned it, I was unaware that there was serious doubt about the facts of the matter.

I did pretty much agree with PZ's analysis--cool thing life can do, sure; "alien arsenic life" not so much.

Redfield posted her first doubts at Pharyngula.

Some of my colleagues have a saying: If it's in Science or Nature, it's probably wrong. And the NASA publicity machine can be ... over-enthusiastic at times, and certainly prone to catchy metaphors that reduce actual scientists to giggles.

And if it's in New Scientist it's nearly always wrong. Well, if it's in the biological sciences...

The problem is, really, that it's been deeply over-hyped, and if it does turn out to be wrong most people will never find out, while if it turns out to be right an aura of scepticism will hang over it forever.

*headdesk* I was so convinced. I guess there's a reason I didn't take sciences beyond GCSE...

I'm no scientist either - my qualification in that area end with A level biology (in 1967) - but I have read a lot of books and learned to be sceptical, even before I started hanging around such websites as Pharyngula, Why Evolution is True, Bad Science, Respectful Insolence, Metamagician, Butterflies and Wheels, Bad Astronomy etc.

Edited at 2010-12-08 08:34 am (UTC)

I just tracked down this piece on NASA's own website. NASA lied shamelessly, claiming the arsenic-loving bacteria were "discovered" in Lake Mono. The article says:

"The idea of alternative biochemistries for life is common in science fiction," said Carl Pilcher, director of the NASA Astrobiology Institute at the agency's Ames Research Center in Moffett Field, Calif. "Until now a life form using arsenic as a building block was only theoretical, but now we know such life exists in Mono Lake."

Pilcher lied shamelessly with that statement. I'm disgusted with NASA.

Well, if the research is accurate then I suppose that every part of that statement is true (the bacteria used do come from Mono Lake) but the overall effect is a piece of appalling spin. See ellarien below above. Those 'colleagues' she's talking about? Solar researchers at the University of Arizona at Tucson.

Edited at 2010-12-08 08:27 am (UTC)

The bacteria in question were descended from ones that came from Mono lake, and were subjected to strenuous selective breeding. There's a huge difference.

Of course there is.

But the strain of bacteria came from the lake... just a couple of missing words, omitted because, after all, who cares about scientific accuracy.

And now, as you are probably aware, the scientists involved are refusing to engage with their critics (and Richard Dawkins, among others, expressed some unease about the paper some days ago - though as it was in comments on Richard Dawkins net it didn't get much prominence, which is probably how he preferred it, not being a microbiologist an' all.) Said scientists say that the debate should take place in the pages of scientific magazines and be reviewed before publication. This would be fine if they hadn't been conducting their own publication via press conference.


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