Scientists Find a Way to Collect Human DNA Samples from Skin Cells Shed in the Air – Science & Tech News
In a groundbreaking proof-of-concept test, scientists have succeeded in extracting human DNA samples from the air that could be used for forensic investigations.
Environmental DNA (eDNA) is an emerging area where scientists can carry out bio-monitoring and ecological research by examining the environment for DNA that is later analyzed.
It used to be used in bodies of water and from substances such as soil and snow. Now researchers at Queen Mary University of London have successfully collected eDNA samples from the air.
eDNA comes from a number of sources, including saliva, urine, and skin cells, which are filtered out of substrates like water, or in this case air.
It has become an important tool to help scientists identify species in different environments, but until now no one had tested whether this could be done with thin air.
To test whether they could collect eDNA from mammals, the one designed by Dr. Elizabeth Clare led the team on a colony of nude mole rats that had lived in a special room for more than a year and therefore likely had a significant amount of sloughed skin cells in the environment.
Using commercially available filters and air pumps, the team collected air and particle samples for examination in sterile plastic chambers. The samples were then genetically sequenced.
They found that the eDNA samples they collected contained not only cells shed by the nude mole rats, but also cells shed by the people who cared for them.
“That was the first thing we all discussed and said, ‘Well, isn’t that awful? It’s so contaminated with human DNA,'” said Dr. Clare Motherboard in an interview on the study.
“And then we thought, ‘No, that’s a different form of DNA. We’re just mammals in the environment, too.'”
The paper, published in the journal PeerJ, describes itself as evidence that “air can for the first time also be a useful substrate for the collection of environmental DNA from animal life”.
“Our results suggest that there is strong potential for using air as a source of DNA,” the researchers write.
“In particular, we suspect that airDNA will be useful in tight spaces such as man-made structures, tree hollows, caves and underground systems where the dilution effects can be minimal and mixed groups of species are difficult to visually examine (e.g. dark or inaccessible).”
They added that, while not their goal, they realize that since the air samples contained human DNA, the technology could find application in forensic investigations, particularly forensic archeology in caves or similar locations.
They caution, however, that the potential of air as a source of DNA in forensics “can also be a contaminant that can flood target trace sources,” and stress that much more work may be required.