Researchers have shown for the first time that animal DNA – including human DNA – can be collected from the air via so-called “environmental DNA” (or eDNA).
This discovery opens up new possibilities for the criminal forensics because it does not require hair follicles or other body tissue.
The new study, authored by researchers at Queen Mary University of London, was published March 31 in the journal PeerJ.
What is environmental DNA good for?
Living organisms such as plants and animals constantly release DNA into their environment.
Environmental DNA has become an increasingly useful tool for scientists to determine which species live in a given environment.
But so far, research has largely focused on collecting eDNA from water and, to a lesser extent, from soil.
For example, scientists have increasingly been collecting environmental DNA from aquatic environments to monitor fish populations or to look for invasive species.
“Many scientists have speculated about this,” said lead author Elizabeth Clare. “But we couldn’t find any published case where anyone had actually tested for animal DNA in the air.”
In this new study, the researchers looked at whether they could collect eDNA from air samples.
First, they tested the air in a room where several rodents (particularly naked mole rats) lived. They then examined that air to look for DNA sequences.
The team successfully showed that ‘airborne DNA sampling’ detected DNA from the rodents in the room itself.
Human DNA in the air: potential forensic DNA applications
“We also found human DNA in all of our samples,” Clare said, “and we didn’t expect that. ”
Human DNA most likely came from the mole rat keepers.
“At first we thought this was a contaminant.” Clare said, “But we realized that this raises some interesting questions about how this might be used in archeology or criminal forensics.”
“The unexpected side effect of collecting human DNA is also really interesting, and we’re now discussing what we can do with this type of technology,” she said.
Using environmental DNA for surveillance difficult-to-access species
“We are aware that there are other really serious applications of the technology,” added Clare.
“Human DNA in the air could open up new possibilities and forensic analysis for us, but the same method we use should also be able to identify microbes and pathogens, pollen and fungal spores.”
Although the human DNA perspective is perhaps the most interesting aspect for the general public, the real purpose of the study was e.g. ecologists or conservationists who often work with animals that are difficult to access.
Using environmental DNA would provide an efficient and non-invasive way to monitor biological environments, such as in caves, tree cavities, or underground burrows, “without actually having to disturb them or get really close,” explains Clare said.
Commercialization of eDNA
Researchers are now working with commercial companies to advance this technology.
“What began as an attempt to see if this approach could be used for ecological assessments,” Clare said, “has now become much more, with potential applications in forensics, anthropology, and even medicine.”
An example of a medical application would be analyzing the transmission of airborne diseases.
“Right now, social distancing guidelines are based on physics and estimates of how far virus particles can travel,” Clare said, “but with this technique, we could actually take aerial samples and real global evidence.” in support of such policies.”
“The main question we are working on now is how far this ‘air DNA’ can travel,” Clare said, “and how big the space can be in and still recognize the species that are present.”
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Study: “eDNAir: Proof of concept that animal DNA can be recovered from air samples”Authors: Elizabeth L. Clare, Chloe Economou, Chris G. Faulkes, James D. Gilbert, Frances Bennett, Rosie Drinkwater, and Joanne E. LittlefairPublished in: PeerJ Published date: 31. March 2021DOI:https://doi.org/10.7717/peerj.11030Photo:by Alexandra from Pixabay
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