Scientists manage to capture DNA in the air
Researchers from the University of Copenhagen have invented a way to “vacuum” DNA from the air.
With the new technology – the common environmental DNA technology – researchers can discover which animal species are found nearby. They have tested it in the Zoo in Copenhagen, where they have filtered air in the okapi stable, the rainforest hall and among the enclosures.
– We were amazed when we saw results. By vacuuming DNA from the air, we registered 49 animal species. Both mammals, birds, frogs, reptiles and fish. In the rainforest hall, we could actually register the sloth, the boa and the guppies swimming around in a small pond, says Bohmann.
She leads the Danish study and is a researcher at the GLOBE Institute at the University of Copenhagen.
– Outdoors we could register many of the animals that have access to an area in the garden – for example ostrich, guinea fowl, giraffe, zebra, impala, okapi and rhino.
Philip Francis Thomsen, researcher at the Department of Biology at Aarhus University, is also surprised by the results.
– It’s really interesting. It is very surprising that the air contains such large amounts of DNA, he says.
– There are no scientists have talked about for a long time. But no one has researched it properly before. It is a smart setup, because by setting it up in the Zoo, they have animals that are not found wild in Denmark. They mimic natural conditions such that it is like standing in Africa or in Southeast Asia with large mammals in the area. It’s a pretty smart place to start.
An incredible idea
The study has been published in the scientific journal Current biology.
But the researchers were not sure of success when they started in 2018.
– We did not think it would work, says Kristine Bohmann.
Because it was an incredible idea to “vacuum” DNA from the air. But it was also the purpose of the grant from the Villum Foundation that Bohmann applied for.
The special type of grant is for daring ideas.
– We tried to come up with daring ideas. But it was difficult. I became so frustrated that I exclaimed: It must be wilder. As wild as vacuuming DNA from the air. And then one of my colleagues saw: “There we have it!”, Bohmann says excitedly.
In the Zoo
It is usually a huge job to map out which animal species are found in an area. Because it requires that you see the animals with the naked eye, or that you film them with a game camera. You can also register feces or traces. But the method is time consuming.
Therefore, there is also a great potential in the solution for the researchers from the University of Copenhagen: a «DNA vacuum cleaner».
Together with postdoctoral fellow Christina Lynggard, Bohmann and the other researchers set out to test different methods of filtering the animals’ DNA from the air:
- Such a water vacuum cleaner – which the researchers refer to as a monster that went on electricity – where DNA in the air was sucked into water (1.7 liters of sterile water for each sample).
- A fan that is also used to cool computers. The fan sucked air in over a filter which then captured the DNA. The researchers tested it in two sizes: The smallest was not much bigger than a golf ball.
In total, they collected 40 air samples in the Copenhagen Zoo with the three «vacuum cleaners».
– We needed a place, there are many different species of animals, and there are known locations and numbers. And since we work at the University of Copenhagen, we have it close by, namely the Zoo, says Bohmann.
– The smart thing about the Zoo is that most of the animals found here are not found elsewhere in the local area. So if, for example, we detected DNA from flamingo, we could be sure it was real flamingo. So it was the perfect place.
The research group is testing the three different vacuum cleaners at three locations in the Zoo; in the okapistallen, the rainforest hall and among the enclosures.
In the laboratory
After collecting the samples, they decided to create a new laboratory to analyze them.
– We cleaned a room and cleaned it. We actually took samples of the air in the laboratory to be sure that there was no animal DNA there, says Christina Lynggard.
– Air is a challenging material to work with because it is found everywhere. This means the risk of cleaning high hay. And we wanted to make sure that the species we recorded actually came from the Zoo and not from our own laboratory. Therefore, we used extremely strict environmental DNA methods.
Most of the animal species that the researchers registered live in captivity at the Zoo. But not all. The researchers also recorded DNA from animals found outside the Zoo – such as dogs, cats, mice, rats and squirrels. And they also recorded three particular fish species.
Therefore, they first thought that the samples had been contaminated.
– When we saw the three fish species in the results of our results, so we can steal in our results. We called Mads Frost Bertelsen, who is the zoo’s director at the Zoo, and mentioned that it might have been contamination of our samples, Kristine Bohmann explains.
But he quickly reassured them when he replied, “No, no, just take it easy. We feed the animals with those fish. “
Must be tested in nature
Although Philip Francis Thomsen is impressed with the researchers’ work, he points out that it must of course be tested in nature.
– It’s going to be fun. The next step is to go out into a natural ecosystem, like the rainforest or savannah, and set up game cameras and filter the air for DNA and then compare the two methods. One of the things we also do not know is how far DNA spreads in the air. This should also be investigated, says Thomsen.
And that is what the research group is now throwing itself at. Kristine Bohmann is establishing a research group at the GLOBE Institute which will focus on airborne environmental DNA to map animals in nature.
Protects biological diversity
In parallel with the Danish research group, English researchers from Queen Mary University of London worked with a similar project and Hamerton Zoo Park.
The two research groups decided to contact the journal Current Biology so that the two studies could be published side by side.
The English research team used a different method to collect DNA. In its over 70 air samples from various locations in the park, they found DNA from 25 different animal species. 17 were known animals from the park, while others were wild animals from the surrounding area.
The new techniques come after environmental DNA in a few years has become a common technique for mapping species in aquatic environments.
The two research groups hope that the new method can map which animals are found in a specific area.
This is especially true of true or invasive species.
And it can help protect biodiversity.
– Well, we have demonstrated the technology in zoos. Now we have to go out into nature and see if it can be used in different habitats or ecosystems. The question is whether it can be used in both dense rainforest and more open areas, says Kristine Bohmann.
And what improvements to the method are needed? Once the researchers have found out, the method can, for example, be used to detect the presence of endangered species, and it will contribute knowledge to improve nature conservation measures, Bohmann explains.
– We are in a huge crisis for biological diversity, and all new tools are welcome.
Philip Francis Thomsen agrees.
– All the new environmental DNA methods that are coming can help us improve nature monitoring, for example if you want to know how many species there are in a nature area, he says. – Anything that can give us more knowledge about endangered species can help us preserve them.
References:
Christina Lynggaard et al .: Airborne environmental DNA for monitoring terrestrial vertebrates. Current biology, 2022. DOI: 10.1016 / j.cub.2021.12.014
Elizabeth L. Clare et al .: Measurement of biodiversity from DNA in the air. Current biology, 2022. DOI: 10.1016 / j.cub.2021.11.064
© Videnskab.dk. Translated by Lars Nygaard for forskning.no. Read the original case on videnskab.dk here.