A major discovery for biodiversity: DNA fragments are available in the ambient air

This is a discovery that could allow monitoring of living organisms on an unprecedented scale. A million species are now endangered according to a UN report, “one of the greatest problems facing the planet today is the accelerating loss of the biodiversity says Elizabeth Clare, istant professor at York University in Toronto. His team recently worked on the possibility of studying owls, hedgehogs, mushrooms, etc. from tiny traces of DNA present in the air. The article, to which she is a signatory, was published in “Current Biology” on Monday, June 5.

More than 180 species of plants and animals already identified

The principle is simple, living beings disperse fragments of their DNA in several forms (hair, pollen, secretions, etc.), this is called environmental DNA (eDNA). Well known to researchers, this eDNA can be sampled from environments (river, earth, tree moss) and analyzed to identify diversity. These samples have so far been made on a small scale, and make it possible to study the populations of very localized areas.

The good idea of ​​the York University researchers was to analyze the filters of the stations air pollution measurement. This new tool paves the way for a large-scale study. For the article, the researchers placed their tag in London and Scotland. “By testing just two locations, we found environmental DNA evidence for over 180 different plants and animals,” Clare says.

“Almost every country has an air pollution monitoring system or network,” confirms Joanne Littlefair, of Queen Mary University of London (UK) and lead author of the article. There are therefore thousands of stations around the world that capture, for the moment without processing data, on biodiversity. This is good news for research. “We will get in touch with the researchers to discuss the technical aspects. This strategy is of particular interest to us”, explains Antoine Trouche, engineer at Airparif, the Ile-de-France air quality monitoring network who imagines deploying it by 2030.

For this, it will first be necessary to specify certain variables, such as the rate of degradation of the eDNA once filtered. Antoine Trouche is enthusiastic “There are around fifty air measurement stations in Île-de-France, and just as many in each region. We could potentially study the biodiversity of the entire French territory, overseas territories included. »

Our self-service DNA?

In a study, published on May 15, 2023 in “Nature ecology & evolution”, David Buffy mentioned several ethical questions raised by these captures of human eDNA. A professor at the University of Florida, he wishes to warn, “society and regulators must decide what to do with the recovered human genetic information and in what context to use it”. He mentions in particular questions of confidentiality, the risks of piracy of genetic data, and the absence of prior consent, since it is impossible to know in advance from whom DNA will be recovered.

So is our DNA available for self-service? Yes and no, answers Elizabeth Clare. Humans being an animal like any other, their DNA can be captured. “The method we use only looks for very small DNA fragments. It’s just enough to identify the species, but nothing more. According to the researcher, the samples used do not make it possible to identify the individuals present. “We could say humans were present,” but nothing else.

She adds that filtering ambient air is far from being the most effective way. “Many countries continue to dump raw sewage into waterways,” which theoretically allows the collection of human eDNA. Observing the ambient air would therefore not increase the risks.

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