The Parallax View

Well, this topic is a bit obscure but (I think, at least) fascinating.  As most people know, over the last decade or two there has been a revolution in the ability of scientists to unpack the information locked in DNA and use that information to aide criminal investigations and to better understanding disease.  Equally huge advances have been made in the use of genetic data in evolutionary biology--understanding the relationship of living creatures to each other: who's related to whom and how closely; how populations are structured; and when all the differences between different kinds of animals and plants arose.

photo of a model of a DNA strandAs it turns out, all of this has enormous consequences for decisions about what populations of plants and animals get protected by the federal government. That's because the Endangered Species Act defines "species" to include both "subspecies" and even distinct populations in some circumstances.  And often, the line that defines these various categories can get quite blurry.  Now, you would think that genetics could sharpen that line for us--and it can.  But it can often cloud the picture even further.  That's because the answer that you get from genetic studies often is very much dependent on where and how closely you look.

NRDC Staff Scientist Sylvia Fallon, a PhD geneticist, spent the last two years examining virtually every decision made by the federal government under the Endangered Species Act over the last decade that relied to some degree on genetics.  She just published her findings in Conservation Biology (subscription required).  Sylvia uncovered some pretty interesting stuff, including:

  • Genetic studies are incredibly influential: in 80 percent of the cases where studies identified genetic distinctions between groups of organisms the federal government decided to protect the genetically distinct group. The reverse was also true: in 80 percent of the cases where genetic studies failed to find a distinction.
  • But amount and type of data that was used in these studies varied enormously.  And that had read consequences: studies that used less data were much less likely to identify genetic distinctions that those used more.  And the type of data examined also was quite diverse

All of this strongly suggests that not all organisms receive equal consideration during their evaluations.  In part, that's because the federal government usually doesn't spend money to do independent genetic analysis itself; in part, it's because the Endangered Species Act requires the government to rely on the best available science available; but, in large part, it's because currently there are no rules or guidelines that federal biologists can turn to to help them evaluate how seriously to take any particular genetic study. 

We hear that such guidelines may be in the works.  We'll be watching.  In the meantime, NRDC is developing our own guidelines that we think biologists should follow when evaluating genetic data under the Endangered Species Act.

About the Authors

Andrew Wetzler

Chief Program Officer

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