Scientists Are Vacuuming DNA Out of Thin Air

More than a decade ago, research began to describe the detection of DNA released by organisms into their environments. For the last several years, this environmental DNA has allowed scientists, including those at the US Geological Survey, to get a handle on the distribution and abundance of small, rare, or little-known species in water. It’s also been used to find traces of ancient humans in soil. Now, the reach of eDNA is expanding even further. "One thing that we've discovered in eDNA research is really that any environmental medium (water, soil, snow, etc.) has the potential to harbor DNA that we can sample," USGS research biologist Stephen F. Spear tells NPR. Indeed, in two new studies, researchers show DNA can also be pulled from air.

Using a commercial vacuum, which was rather noisy, and a quieter 3D-printed device equipped with a small fan, a team at the University of Copenhagen was able to retrieve DNA from 49 species at the Copenhagen Zoo, from giraffes to elephants. "We even detected the guppy that was living in the pond in the rainforest house," Kristine Bohmann, lead author of one of the pair of studies published Thursday in Current Biology, tells NPR. "It was just absolutely mind-blowing." Separately, a team in England led by Elizabeth Clare was able to detect DNA from 25 zoo species, a critically endangered hedgehog seen wandering nearby, and chicken and beef used as feed. In a lab setting, they even detected dog DNA, apparently carried on a technician's clothing, per CBC News.

Questions remain as some species present were not detected. It's also unclear what exactly is being detected, whether it be skin, saliva, urine, or feces. But "I see the current state of airborne eDNA as very similar to when the first papers on aquatic eDNA came out over a decade ago," says Spear, who believes further research will determine best methods for the practice, as well as any limitations. Clare is dreaming big, envisioning samplers placed all over the planet that can pull DNA from soil, water, rain, and air—including that of rare species or those thought to be extinct—and beam the resulting data to servers as part of a wildlife monitoring system. She notes her initial idea of extracting eDNA from air seemed crazy, too, per NPR. But now, "we are literally sucking DNA out of the sky." (More DNA stories.)