Big biodiversity discovery: DNA fragments available in ambient air

This discovery could allow observation of living organisms on an unprecedented scale. According to a UN report, one million species are currently threatened with extinction. “One of the biggest challenges facing the planet today is the accelerating loss of biodiversity,” says Elizabeth Clare, assistant professor at York University in Toronto. His team has recently been working on the possibility of studying owls, hedgehogs, mushrooms, etc. from tiny traces of DNA present in the air. The article she signed off with was published in Current Biology on Monday, June 5th.

More than 180 species of plants and animals have already been identified.

The principle is simple, living things distribute 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 taken from the environment (river, land, moss on a tree) and analyzed for diversity. These specimens have so far been made on a small scale and allow the study of populations in very limited areas.

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

“Almost every country has an air pollution monitoring system or network,” confirms Joan Littlefair of Queen Mary University of London (UK) and lead author of the paper. Thus, there are thousands of stations around the world that record biodiversity, so far without data processing. This is good news for research. “We will contact the researchers to discuss the technical aspects. This strategy is of particular interest to us,” explains Antoine Trouche, engineer at Airparif, an air quality monitoring network in Ile-de-France that plans to deploy it by 2030.

To do this, it will first be necessary to specify certain variables, such as the rate of eDNA degradation after filtration. Antoine Troche is enthusiastic: “Ile-de-France has about fifty air measurement stations, and the same number in each region. Potentially, we could study the biodiversity of the entire territory of France, including overseas territories. »

Our DNA of self-service?

In a study published May 15, 2023 in the journal Ecology and Evolution of Nature, David Buffy has mentioned several ethical issues raised by this capture of human eDNA. A professor at the University of Florida, he would like to warn that “society and regulators must decide what to do with recovered human genetic information and in what context to use it.” He mentions, in particular, privacy issues, the risks of genetic data piracy, and the lack of prior consent, since it is impossible to know in advance who will have their DNA extracted.

So is our DNA available for self-service? Yes and no, Elizabeth Clare replies. Humans are animals like any other, and their DNA can be captured. “The method we use only looks for very small pieces of DNA. This is enough to determine the species, but no more. According to the researcher, the samples used do not allow the identification of those present. “We could say that people were present,” but nothing more.

She adds that filtering the ambient air is far from the most efficient way. “Many countries continue to dump raw sewage into waterways,” theoretically allowing the collection of human eDNA. Thus, observing the surrounding air does not increase the risks.