TITLE: An Example of Science in Action AUTHOR: Eugene Wallingford DATE: February 16, 2015 4:15 PM DESC: ----- BODY: Here is another interesting piece from The New Yorker, this time on an example of science in action. Jon Krakauer is the author of Into the Wild, 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 When those tests undermine the claim, it is withdrawn.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:
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 Ethnobotany Research & Applications, that "no chemical basis for toxicity could be found" in H. alpinum seeds.
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 alkaloid 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. -----