Scientists can now gather and analyse DNA extracted from thin air, and the ground-breaking new tools used to do so could revolutionise how endangered animals and natural habitats are researched and protected.
By collecting samples in Copenhagen Zoo in Denmark and Hamerton Zoo Park in the United Kingdom, two groups of researchers, one from Denmark and the other from the United Kingdom and Canada, tested whether airborne DNA could be used to detect different animal species.
When living species excrete waste, bleed, or shed skin or fur, they release genetic material known as eDNA into the environment.
Conservation biologists have recently sequenced waterborne eDNA to follow some species in aquatic habitats, such as the UK’s great crested newt population.
Monitoring airborne eDNA, on the other hand, proved more difficult due to the fact that it is more diluted in air than in water.
Despite the fact that the two research teams employed different ways to filter DNA from the air, both were effective in identifying the animals lurking close, both inside and outside the zoo.
On Thursday, their findings were published in the journal Current Biology in two proof-of-concept experiments.
According to UK study lead author Elizabeth Clare, an assistant professor at York University in Canada and a former senior lecturer at Queen Mary University of London, where she conducted the research, the team at the Hamerton Zoo Park was able to identify DNA from 25 different species of animals, including tigers, lemurs, and dingoes.
“We were even able to harvest eDNA from animals hundreds of metres away without a noticeable loss in concentration, as well as from outside sealed buildings. The animals were inside, but their DNA was escaping,” Clare said in a news release.
A total of 49 vertebrate species, including 30 mammals, were discovered by the Copenhagen team.
“We were astonished when we saw the results,” said Kristine Bohmann, an associate professor from the Globe Institute at the University of Copenhagen and the lead author of the Danish study, in the statement.
“In just 40 samples, we detected 49 species spanning mammal, bird, amphibian, reptile and fish,” Bohmann said. “In the Rainforest House (at the Copenhagen Zoo) we even detected the guppies in the pond, the two-toed sloth and the boa. When sampling air in just one outdoor site, we detected many of the animals with access to an outdoor enclosure in that part of the zoo, for example kea, ostrich and rhino.”
The Copenhagen team utilised a fan to take air from the zoo and its environs, which may carry genetic material in the form of breath, saliva, or fur — or anything small enough to become airborne and float in the air.
After that, the air was filtered, and DNA was collected and copied before sequencing. The DNA sequences were then matched to a reference database to determine which animal species they belonged to.
Both teams also discovered animals that did not belong to the zoos. They discovered animals living in the surrounding areas, including the Eurasian hedgehog, which was discovered outside of Hamerton Zoo and was endangered in the UK, as well as the water vole and red squirrel near the Copenhagen Zoo.