

Arsenic life does not exist after all... - t3rcio
http://www.newscientist.com/article/mg21328493.300-arsenic-life-does-not-exist-after-all.html

======
tokenadult
The claim that living things could use the usual molecules, just with arsenic
switched for phosphorus in their DNA, was an extraordinary claim, and such a
claim requires extraordinary evidence.

[http://skeptico.blogs.com/skeptico/2008/01/extraordinary-c.h...](http://skeptico.blogs.com/skeptico/2008/01/extraordinary-c.html)

But the first report about "arsenic-based life" was no more than a preliminary
research finding announced in a press event by the study sponsor, and such an
announcement is not enough to establish a new body of scientific fact.

<http://norvig.com/experiment-design.html>

The specific preliminary finding was criticized right away for sloppiness of
technique and a rush to reach an unwarranted conclusion,

[http://scienceblogs.com/pharyngula/2010/12/its_not_an_arseni...](http://scienceblogs.com/pharyngula/2010/12/its_not_an_arsenic-
based_life.php)

[http://rrresearch.fieldofscience.com/2011/08/first-
evidence-...](http://rrresearch.fieldofscience.com/2011/08/first-evidence-
refuting-wolfe-simon-et.html)

so the journal slated to publish the preliminary finding had to invite in
critiques of the finding to save its own reputation.

[http://www.wired.com/wiredscience/2011/05/science-
publishes-...](http://www.wired.com/wiredscience/2011/05/science-publishes-
arsenic-is-life-responses-game-on/)

Science is all about reproducible results, so much so that there is a humor
magazine for scientists called the Journal of Irreproducible Results.

<http://www.jir.com/>

The headline in New Scientist, a British popular magazine about science
(something like Scientific American in the United States), which has been
published since before I was born, is correct. There isn't any reliable
evidence of arsenic-based life living anywhere within reach of scientists on
earth. Not now, and not last year. The best summary of the current evidence,
after the efforts of many more careful researchers, is "arsenic life does not
exist after all," period (as an American would say), full stop (as a Briton
might say).

------
robinhouston
I don’t think the scientific community really bought it in the first place.
The original experiment wasn’t especially rigorous; e.g. see Rosie Redfield’s
review [http://rrresearch.fieldofscience.com/2010/12/arsenic-
associa...](http://rrresearch.fieldofscience.com/2010/12/arsenic-associated-
bacteria-nasas.html)

And then the authors declined to respond in detail to any of the specific
criticisms that had been made by other scientists, which is very rarely a good
sign.

------
biasedstudy
Serious biologists were very skeptical from the start :
[http://omicsomics.blogspot.com/2010/12/arsenic-and-new-
micro...](http://omicsomics.blogspot.com/2010/12/arsenic-and-new-
microbes.html)

Soon, there were lots of questions :
[http://pipeline.corante.com/archives/2011/06/01/return_of_th...](http://pipeline.corante.com/archives/2011/06/01/return_of_the_arsenic_bacterium.php)

I'm thinking NASA is good at space exploration, not so good at biology.

------
rylz
The title is a bit misleading. One other lab's failure to reproduce the
results does not prove invalidity of the original publication. It certainly
raises some eyebrows, but it makes sense to wait and see what comes of Wolfe-
Simon's further analysis before we declare that arsenic life definitely does
not exist.

~~~
Tim-Boss
Agreed; a sensationalist title adds nothing to an otherwise accurate article!

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nwatson
Even if the organisms were shown to swap out phosphorus for arsenic in some
instances in their DNA, would that be surprising? Arsenic comes from the same
column in the periodic table as phosphorus, and exhibits many of the same
macro chemical properties as phosphorus.

It would be like a software engineer swapping out their optimized, say, C++
string library, for one that was less optimal but perhaps took less space or
ran better in a constrained embedded environment. Arsenic might not be optimal
but it's what's available, what can be used.

In the software case you'd probably be OK but run more slowly than otherwise,
or else maybe you'd stumble when for some strange reason the sub-optimal
string library didn't guarantee thread-safe read operations. The arsenic could
similarly trip up the organism in some cases.

~~~
synparb
I think your analogy is not quite right. Although seemingly similar, inserting
Arsenic into DNA would be like taking a very large and complicated piece of
software that was fundamentally dependent on the precise API of a component,
and then changing that API to make it largely incompatible, thus requiring a
large piece of your software to be re-written. It is not just like swapping in
a suboptimal component that has no downstream effects.

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veyron
I've never heard of new scientist. Is it a real science journal or
sensationalist? (based on this article I'd guess the latter)

~~~
corin_
It's an English magazine that's somewhere inbetween your two options.
Generally their reporting is pretty good and they avoid headlines for the sake
of headlines, however they do put a lot of focus on making their content
understandable to non-scientists - it's aimed at smart, curious people, not
scientists.

An example of this is their "last word" feature, where they take a question
from a reader and let anyone write in with answers - these are usually random
questions like "Why is the sky blue?" or "If it's raining, will I get less wet
if I run than if I walk?" They've also released two or three Last Word
compilation books.

~~~
coob
If anyone is interested in the sound of this there is something similar over
on this subreddit:

<http://reddit.com/r/askscience>

~~~
SilasX
More direct, permanent link:

[http://www.reddit.com/r/science/comments/oxz9b/arsenic_life_...](http://www.reddit.com/r/science/comments/oxz9b/arsenic_life_does_not_exist_after_all/)

~~~
coob
I wasn't talking about the article, but the 'ask for a scientific answer' type
service.

------
geuis
Summary: Scientist B failed to replicate the results of Scientist A. Scientist
A stands by her continuing research. Research continues and is not definitive
yet. New Scientist has a slow news days and publishes said results, mucking up
an extra controversy for the day and getting a few more clicks through to
their website.

