Scientists vacuumed animal DNA out of thin air for the first time
On a dreary winter day in December of 2020, ecologist Elizabeth Clare strolled
On a dreary winter day in December of 2020, ecologist Elizabeth Clare strolled through the Hamerton Zoo Park in England wielding a small vacuum pump. She paused outside of animal enclosures, holding aloft a flexible tube attached to the machine. Her mission: suck animal DNA out of thin air.
The ability to sniff out animals’ airborne genetic material has been on scientists’ wish list for over a decade. DNA collected from water has been used to track aquatic species, including salmon and sharks (SN: 5/7/18). Scientists knew they could use environmental DNA, or eDNA, in the air to monitor land-based species — if only they could trap it. Now, researchers have done just that by using vacuums, two independent groups report January 6 in Current Biology.
“It’s such a crazy idea,” says Clare, of York University in Toronto. “We’re vacuuming DNA out of the sky.”
The idea came to Clare, who did the work while at Queen Mary University of London, during a previous experiment in which she sampled air outside naked mole rat burrows. At the zoo, Clare and colleagues ran the vacuum pump for half-hour sessions in and around animal enclosures, collecting 72 samples from 20 sites. Then, the team took the material ensnared in the pump’s filter back to the lab for analysis.
Meanwhile, another team at the University of Copenhagen was unknowingly chasing the same idea. Biologist Kristine Bohmann and colleagues sought to trap airborne DNA at the Copenhagen Zoo using tiny fans similar to the ones that cool down computers. The team also experimented with a vacuum. Deploying their contraptions between 30 minutes and 30 hours at the tropical house, stables and in open air, the researchers found that both the fan and vacuum method collected ample animal DNA.
“It was so much fun,” Bohmann says. “It felt like we could just play around and be creative.”
To test the technique, both teams used a zoo for its roster of animals. Air in the wild could host DNA from unpredictable places, but at zoos, the researchers could cross-reference the captured airborne DNA with animals listed in exhibits. That allowed the scientists to confirm the source of the DNA, and see how far it traveled between enclosures.