AILSA CHANG, HOST:
A key part of protecting endangered species is figuring out where they're living, and that can be tricky. But now two teams of scientists have discovered a technique that might help. NPR's Geoff Brumfiel has more.
GEOFF BRUMFIEL, BYLINE: A few years ago, a Danish research foundation put out a call for unusual ideas. Kristine Bohmann wanted to come up with a crazy experiment but couldn't think of anything.
KRISTINE BOHMANN: And in the end, I got so frustrated that I just blurted out, like, no, it has to be crazier. It has to be like vacuuming animal DNA out of air.
BRUMFIEL: It does sound crazy, sucking random bits of animal DNA out of the sky. Bohmann, a professor at the University of Copenhagen, proposed it got funding - eventually - and went to work.
BOHMANN: At first we had the obstacle of figuring out how on earth do we vacuum DNA out of thin air?
BRUMFIEL: With a vacuum, it turns out. Like, they literally used a vacuum cleaner, and it worked. So that was easy. But to make the experiment successful, they also needed a good place to look for animal DNA, a place with unique animals, preferably in enclosed spaces.
BOHMANN: And then we realized, we are based in Copenhagen. We have that literally in our backyard. We have the Copenhagen Zoo.
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UNIDENTIFIED PERSON: (Speaking Danish).
BRUMFIEL: The zoo was custom built for this experiment. Most of the animals are non-native, so they really stick out in a DNA analysis.
BOHMANN: So if we detect a flamingo, well, we are sure that it's not coming from anywhere else than that flamingo enclosure.
BRUMFIEL: They took samples from around the zoo, and they were shocked. They picked up 49 animal species - rhinos, giraffes, elephants.
BOHMANN: We even detected the guppy that was living in the pond in the rainforest house through vacuuming of the air in there. So it was just absolutely mind-blowing.
BRUMFIEL: They took their crazy result, wrote it up as a scientific paper - and then, as they were getting ready to publish, something even crazier happened.
BOHMANN: We had a deadline to submit it to a journal. And two days before that, I start getting emails and texts saying, have you seen this other study?
BRUMFIEL: The other study was led by Elizabeth Clare of York University in Toronto, Canada. It turns out her team had done pretty much the same thing at a zoo in the U.K., and she didn't know about the Copenhagen work.
ELIZABETH CLARE: I woke up to this flurry of text messages from my co-author saying, there's another paper. Have you seen this?
BRUMFIEL: So the two groups got in touch and decided to publish their findings as a pair.
CLARE: We are independently confirming that this works to each other and to everybody else. I think we both thought the papers were much stronger together.
BRUMFIEL: The work appears today in the journal Current Biology. Clare says this is just the beginning. There are a lot of unanswered questions, like what is this DNA? Is it skin cells or hair or saliva? Also...
CLARE: There were some species we simply never detected even though we know they were there.
BRUMFIEL: They still don't know why, but Clare says even if sucking DNA out of the air isn't perfect, it's likely to be super useful. It could help find an endangered species in a dense part of the jungle, even if it can't be seen. Ultimately, Clare is thinking even bigger.
CLARE: I have this vision of samplers that are deployed globally that can suck up the DNA from all these different sources - from soil and honey and rain and snow and air and water - sequence them on site, beam the data up to the servers so we can really have a form of global biomonitoring. We don't have a coordinated system for that.
BRUMFIEL: She believes the answers to some of the toughest questions in conservation are literally in front of our faces, hanging in the air.
Geoff Brumfiel, NPR News.
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