Assimilation of genetic material from the atmosphere may be useful for biodiversity monitoring
Ecologist Elizabeth Clare was walking around the Hamerton Zoo Park in England with a little vacuum pump on a bleak winter day in December 2020. Her arms were raised, holding aloft a flexible tube linked to the machine, as she halted outside animal cages. Sucking animal DNA out of thin air is her mission.
For more than a decade, scientists have wanted to be able to detect animals’ airborne genetic material. Salmon and sharks have been tracked using DNA extracted from water (SN: 5/7/18). Environmental DNA (eDNA) might be used to track land-based animals by scientists, but they needed a way to capture it. As of January 6, two different study groups have reported in Current Biology that they’ve done precisely that by employing vacuums.
According to Clare from York University in Toronto, “it’s such an outlandish concept. In other words, “We’re sucking’ DNA from the sky.”
In a previous experiment, Clare, a researcher at the Queen Mary University of London, collected air samples outside the burrows of naked mole rats. At the zoo, Clare and colleagues used the vacuum pump for half-hour periods in and around animal enclosures, collecting 72 samples from 20 spots. The crew then returned to the lab to analyze the material entangled in the pump’s filter.
University of Copenhagen researchers were working on a similar project without realizing it. At the Copenhagen Zoo, biologist Kristine Bohmann and her colleagues tried to capture airborne DNA using tiny fans that are used to cool laptops. A vacuum was also tested by the group. For 30 minutes to 30 hours, researchers used their contraptions in the tropical home, stables, and out in the open to harvest animal DNA.
As Bohmann puts it, “It was a lot of fun.” “It seemed as though we could simply play around and be creative,” said one participant.
In order to test the method, both teams employed animals from a zoo as their subjects. Researchers could cross-reference airborne DNA with display animals at zoos, but the air in the wild may hold DNA from unanticipated areas. As a result, the origin of the DNA could be verified, as well as the distance it traveled between enclosures.
A total of 49 vertebrate species were found in the Copenhagen Zoo by Bohmann and his colleagues. They found okapis (Okapia johnstoni) in the stables and a Dumeril’s ground boa (Acrantophis dumerili) in the rainforest house in the enclosures that had been studied. However, the researchers also found evidence of nearby animals and birds, as well as fish that had been utilized as food. Bohmann recalls, “That was extremely startling.”
Clare’s team discovered 25 unusual species in Hamerton Zoo, including several that were not expected. DNA from meerkats (Suricata suricatta), which dwell 245 meters away, was found in the dingo cage, according to the research team.
Each team’s outcomes were also affected by the presence of zoo visitors. The European hedgehog (Erinaceus europaeus), which is on the verge of extinction in England, was discovered by Clare’s team, whereas mice and domesticated dogs were discovered by Bohmann’s. They also detected traces of human DNA.
Bohmann believes that sucking DNA from the air might be a noninvasive method for tracing the genetic imprints of endangered animals. She argues the technology would be an improvement over video traps, which only operate if a creature happens by.
Neither group was aware the other was working on a similar idea to their own. They became acquainted as a result of stumbling over an early draught of one another’s work on a preprint site. Clare calls it “the most amazing scientific coincidence” of her life or theirs thus far. As a way to ensure the validity of each other’s findings, the teams published their studies together.
Uncertainty surrounds the practical use of this proof-of-concept device. Detection of airborne eDNA in the wild is more difficult due to variables such as weather and wind. Clare believes that airborne eDNA will advance in the same way as aquatic eDNA did in the last decade. “I can’t wait to see this strategy put into action by others.