Earlier last year, a team of scientists demonstrated that animal DNA can be collected from the air — a breakthrough expected to significantly improve conservation efforts, and even potentially revolutionize forensics and epidemiology. Now, scientists decided to take it a step further by conducting a similar study in a non-artificial environment this time — and the results are fascinating.
What is environmental DNA?
As animals interact with their environment, they are shedding DNA, be that in the form of shed skin, fur or scales. Studies have previously managed to detect environmental DNA (eDNA) in soil and water. And more recently, scientists have collected air samples inside a room that had housed naked mole rats and successfully detected the animal’s DNA in those samples.
Following in the footsteps of that previous research, two independent teams have now conducted similar experiments in zoos in a bid to try to pick up air DNA traces of even larger animals.
Detecting animal DNA in the air
For the research, both teams used vacuum devices to capture samples of air from different parts of their chosen zoos. One study used vacuum pumps with sensitive filters to gather over 70 samples from around Hamerton Zoo Park in the UK, taken both inside the animals’ sleeping areas as well as around the zoo’s outdoor section.
“When we analyzed the collected samples, we were able to identify DNA from 25 different species of animals, such as tigers, lemurs and dingoes, 17 of which were known zoo species,” said the study’s lead author Elizabeth Clare. “We were even able to collect eDNA from animals that were hundreds of meters away from where we were testing without a significant drop in the concentration, and even from outside sealed buildings. The animals were inside, but their DNA was escaping.”
The second study took place at three locations in Copenhagen Zoo in Denmark. Here, the researchers used a commercial water-based vacuum and two blower fans to collect air samples in the zoo.
“We were astonished when we saw the results,” said the study’s lead author Kristine Bohmann. “In just 40 samples, we detected 49 species spanning mammal, bird, amphibian, reptile and fish. In the Rainforest House 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 importance of eDNA for conservation
According to the scientists, the techniques pioneered in both studies could help conservationists monitor natural environments, providing a non-invasive way to gather new insights into biodiversity, the status of endangered species, or alert scientists about the presence of invasive species.
Source study: Current Biology — Measuring biodiversity from DNA in the air