TITLE: An Example of Science in Action
AUTHOR: Eugene Wallingford
DATE: February 16, 2015  4:15 PM
DESC: 
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BODY:
Here is
<A HREF="http://www.newyorker.com/books/page-turner/chris-mccandless-died-update">
   another interesting piece</A>
from <EM>The New Yorker</EM>, this time on an example of science
in action.  Jon Krakauer is the author of <EM>Into the Wild</EM>,
about adventurer Chris McCandless.  Eighteen months ago, he
published a claim that McCandless had likely died as a result
of eating the seeds of Hedysarum alpinum, known as wild potato.
Krakauer's theory was based on lab analysis of seeds from the
plant showing that it contained a particular toxic alkaloid.  A
critic of the claim, Tom Clausen, suggested that Krakauer's theory
would be credible only after being subjected to more thorough
testing and published in a peer-reviewed journal.

So that's what Krakauer did.  He worked with the same lab to do
more thorough testing and found that his toxic alkaloid theory
didn't hold up after all.  Instead, detailed analysis found that
Hedysarum alpinum instead contains an amino acid that acts as an
antimetabolite and for which toxicity in animals has been well
documented.  This work went through peer review and is being
published next month in a scientific journal.

That's how science works.  If a claim is challenged by other
scientists, it is subjected to further tests.  When those tests
undermine the claim, it is withdrawn.  Often, though, the same
tests that undermine one hypothesis can point us in the direction
of another and give us the information we need to construct a
better theory.

A cautionary lesson from science also jumps out of this article,
though.  While searching the scientific literature for studies
as part of the re-analysis of Hedysarum alpinum, he found a
paper that pointed him in the direction of toxic non-protein
amino acids.  Krakauer writes:

<BLOCKQUOTE><EM>
 I had missed this article in my earlier searches because
 I had been looking for a toxic alkaloid instead of a
 toxic amino acid.  Clausen had been looking for a toxic
 alkaloid as well, when he and Edward Treadwell reported,
 in a peer-reviewed paper published in the journal
 <U>Ethnobotany Research &amp; Applications</U>, that
<A HREF="http://journals.sfu.ca/era/index.php/era/article/viewFile/180/153">
   "no chemical basis for toxicity could be found"</A>
 in H. alpinum seeds.
</EM></BLOCKQUOTE>

Clausen's team had been looking specifically for alkaloids,
but then concluded more generally that "no chemical basis for
toxicity could be found".  This claim is broader than their
results can support.  Only the narrower claim that they could
find no chemical basis for <EM>alkaloid</EM> toxicity seems
warranted by the evidence.  That is probably the conclusion
Clausen's team should have drawn.  Our conclusions should be
as narraow as possible, given the data.

Anyway, Krakauer has written a fascinating article, accessible
even to a non-biologist like me.  Check it out.
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