The power of environmental DNA

Information about the living world—and about our effects on that world—is essential to responsible management of our natural resources. While technological advances of past decades have revolutionized our understanding of physical processes (think of satellite storm-tracking, for example), techniques for gathering biological information have lagged behind: counting fish or bald eagles (or pigeons or rats, for that matter) remains an expensive, slow, and labor-intensive endeavor.

Because a swath of crucial questions hinge on this kind of biological information—from how many fish we should catch to how many individuals of an endangered species are left—a lack of biological data can leave decisionmaking in the dark and sustainability hard to define or pursue.  

However, improved DNA sequencing techniques and plummeting cost curves could quickly bring biological monitoring up to speed and into the 21^st century. The emerging technology works like this: virtually every cell of every living thing contains DNA, which in turn carries a unique chemical sequence much like a barcode.

Species constantly shed DNA into their environments (in waste products, for example), and we can use the resulting genetic signatures to detect species’ presence and perhaps species’ abundances. Sequencing DNA has become remarkably affordable—what cost $10,000 in 2001 now costs about 12 cents—and so it’s no longer science fiction to think about routinely monitoring far-flung habitats with automated DNA technology.

Several applications of genetic monitoring have already been demonstrated.  These include detecting hard-to-count endangered species in lakes and streams, surveying the Great Lakes basin for invasive carp species, and safeguarding surfers from bacterial outbreaks at beaches.

Such advances are the fruit of years of research on basic science and engineering questions, and represent some of the first practical applications of the resulting knowledge. We might easily imagine uses of environmental genetic sampling that go far beyond the realm of monitoring: optimizing agricultural output based upon the microbial component of soil on an acre-by-acre basis, for instance.

Teams of scientists are working on these and other applications in laboratories around the world. We are involved with one such team—funded by the Packard Foundation and made up of collaborators at Stanford University’s Center for Ocean Solutions and the University of Washington’s College of the Environment—that has begun field-testing one method of detecting and identifying environmental DNA in Monterey Bay, California, comparing these results to those of traditional monitoring by visual means.

If all goes well, we envision piloting the technology for use by state or federal agencies in the next several years. This method may drastically reduce the cost to assess the status and trends of marine resources along the West Coast, while increasing accuracy and reliability.

The ability to sustainably manage natural resources and to meet this century’s greatest challenge—de-coupling an increase in quality-of-life from a concomitant increase in environmental degradation—depends critically upon the ability to understand how humans influence the functions of ecosystems. With the explosive growth of genomic science, it seems likely that these techniques will soon provide precise, actionable information to inform a wide spectrum of decisions that move toward sustainability.

Assistant Professor Ryan Kelly is a geneticist and legal scholar who teaches at the University of Washington. Dr. Kelly may be contacted via www.KellyResearchLab.com. 

Kai Lee is program officer for science at the David & Lucile Packard Foundation. For additional information, visit www.Packard.org. 

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