Forensic police has long been accustomed to tracking DNA at crime scenes, most often found in bodily fluids and hair. A recent discovery by two scientific teams has now demonstrated that this genetic signature can also be found in the air.
As is often the case with scientific breakthroughs, it all began with research far removed from criminalistics. In early 2021, researchers from the University of York in England and the University of Copenhagen in Denmark installed air-sampling devices equipped with filters in two European zoos to collect air samples and analyze their composition. The initial goal was to determine whether this method could be used to identify the animal species present in a natural habitat, monitor them to improve protection, and thus achieve highly accurate tracking of endangered species.
The results of the sequencing went far beyond expectations: in both cases, the scientists detected not only the DNA of numerous animal species but also human genetic material from the individuals conducting the experiment. A first of its kind—and a development that promises to further advance forensic investigation techniques.
Human DNA: a marker unique to each individual.
It was only in the 1980s that criminal investigations began incorporating the search for DNA traces at crime scenes. This breakthrough was pioneered by Alec Jeffreys, a British researcher at the University of Leicester. Once again, the aim of his research was far removed from forensic science: his team was primarily studying the hereditary transmission of certain genetic diseases. Along the way, however, they discovered that portions of the genome’s DNA are unique to each individual. This discovery led, in 1985, to its first practical application. Called upon by police investigating the murder of two young girls, Jeffreys’ laboratory demonstrated—through semen traces collected at the crime scene—that both killings had indeed been committed by the same individual.
DNA in the air: a decisive breakthrough.
Advances in sampling and analysis techniques, along with the launch in 2000 of the French National Automated DNA Database (FNAEG), which today contains nearly 3.5 million genetic profiles, have already revolutionized investigative methods. It is now possible to detect and sequence DNA from even the tiniest traces left behind by an individual—whether perpetrator or victim. This includes blood, semen, or sweat, as well as hair with its root attached. In the absence of a hair bulb, mitochondrial DNA (inherited exclusively from the maternal line) is targeted.
The ability to capture DNA suspended in the air and compare it to that of potential suspects or to entries in existing databases opens up entirely new perspectives for solving the most complex criminal cases.
Sources :
https://leblob.fr/videos/adn-environnemental-une-revolution-dans-air
https://www.science-et-vie.com/technos-et-futur/peut-on-prelever-de-l-adn-dans-l-air-63699
Tous droits réservés - © 2025 Forenseek
