Two teams of scientists—one in Denmark and the other in the UK—came up with the same question at about the same time: Could they identify the animals in an area from DNA that was simply floating in the air?
Testing for "environmental" DNA, or eDNA, isn't a new idea, but most of the time, scientists look for eDNA in the water. DNA in the air is usually so small that it would take a microscope to see it. "We did not think that vacuuming（用真空吸尘器吸）animal DNA from the air would work at first, but the result is pleasantly surprising," said Dr. Kristine Bohmann, one of the scientists on the Copenhagen team.
Neither team knew the other group was working on a similar experiment. One collected samples from different places at Denmark's Copenhagen Zoo, and the other at Hamerton Zoo Park in the UK. The scientists used slightly different methods to collect their samples. But basically, both teams used vacuums and fans to collect extremely tiny bits of DNA onto very high-quality filters （过滤器） .
In the laboratory, they got the DNA from the filters and made copies of it to study. By comparing their samples with examples of DNA from different animals, the scientists were able to identify many different animals at the zoos. The scientists chose to test in zoos because they had scarce animals which are not naturally and easily found in the area. As Dr. Elizabeth Clare who led the UK team said, "There's no other way I would detect DNA from a tiger, except for the zoo's tiger."
Each team only discovered the other experiment after they'd written a paper about their own results. Instead of competing, the two decided to combine their results and publish a paper together.
"We are excited that this new method could be used in the wild. Scientists have been looking for belter ways to track endangered animals without affecting them. If researchers know where animals live, they can do a better job of protecting them. The next step is to figure out how to take this method into nature," says Dr. Bohmann.
