The air you breathe contains the DNA of over a thousand species, including yours.

"I was extremely surprised by the richness of the surveys," says David Duffy. With his team, the geneticist from the University of Florida (USA) took DNA samples from the air at various sites to assess the information that could be extracted from them. Living beings continually release genetic information into the environment. How can we exploit this information?

In this groundbreaking study, David Duffy and his colleagues attempted to sequence all the DNA collected from their samples and then match the resulting sequences with databases using extensive computer processing. This is a novel approach to the study of environmental DNA in the air, for which research had previously favored less cumbersome analysis methods.

“ DNA is of such good quality that it allows us to obtain a huge amount of information.

The result is disconcerting: “ DNA is of such good quality that it allows us to obtain a huge amount of information on ecosystems, at different scales., explains David Duffy. The researchers not only managed to identify more than a thousand species per sample (probably the majority of species around the collection site, the authors estimate), but they also obtained the complete genome of some organisms. The level of detail is such that it is possible to observe the genetic diversity of a population, to identify specific mutations – for example, resistance markers or local adaptations – and even to outline a population structure.

Read alsoDNA can be detected even in the air

“ Before environmental DNA could be used, the only way to assess biodiversity was to involve large teams with diverse expertise, and it took a long time., enthuses David Duffy, This analysis can now be done in less than two days by a single specialist. A delay expected to decrease with progress in genetic sequencing and the computing power of data centers.

A regulatory framework to be put in place

This work, however, raises major ethical questions. While air DNA analysis is a formidable tool for identifying living organisms, human beings are not excluded. In a sample collected from the air in Dublin, Ireland, for example, researchers were able to identify genetic signatures precise enough to provide information on the origins of the region's populations. A regulatory framework urgently needs to be put in place.

To learn more about the sequencing method and the possibilities offered by environmental DNA from air, we invite you to read the article by The Research.