The ocean is full of drifting DNA. The United States needs to collect it, researchers say

U.S. government agencies monitoring fisheries, endangered species, and environmental impacts ought to leverage the DNA present in every drop of seawater, say the organizers of a conference on marine environmental DNA (eDNA), held at Rockefeller University in New York City in November 2018.

Biological surveys based on eDNA are reliable and poised to cut costs and save time, they argue in a report released last week. The report calls for the U.S. National Oceanic and Atmospheric Administration (NOAA) and other government agencies that survey marine life to add the technology to their standard palette of assessment techniques.

Animals leave behind a trail of genetic material as they move through their environment, often in the form of skin cells. Scientists can collect these loose fragments of DNA from soil or water and analyze them to ferret out their source. In the ocean, the DNA trail goes cold after about 24 hours, meaning that any species that shows up in analysis can’t be too far off. For researchers and resource managers trying to find animals in a vast, opaque sea, the technique offers new opportunities.

To sample eDNA, researchers push seawater through a very fine filter. The DNA can then be pulled off the filter, quantitative ecologist Christopher Jerde of the University of California, Santa Barbara, explains. After collecting the DNA from the water sample, researchers can isolate segments of genetic code unique to a species, called genetic markers. These genetic markers can then be compared to a library of such markers to figure out what they came from.