Environmental DNA, or eDNA, has become a crucial tool for ecology research in recent years.
By sampling water, soil or other environmental materials for DNA fragments, researchers can tell that thousands of different species have been in an area without having to observe the actual species passing through.
But it could be used just as easily to spot humans, according to a paper in Nature Ecology & Evolution – and while this might help in medical and forensic investigations, it also raises serious ethical concerns.
The international team of researchers based at the University of Florida, US, showed that it’s easy to find human genomic information in eDNA water and sand samples that were taken while looking for wildlife and pathogens.
This human genetic bycatch (or HGB, as they call it) showed up in every sample they tested.
They could also find human genetic information in samples they’d intentionally collected while looking for human DNA – including in beach footprints, and the air in both occupied and unoccupied rooms.
The only samples free of human DNA were in remote areas that people essentially never visited.
“We’ve been consistently surprised throughout this project at how much human DNA we find and the quality of that DNA,” says senior author Professor David Duffy, a researcher in wildlife disease genomics at the University of Florida.
In some samples, the human DNA quality was high enough that the researchers could identify things like the person’s ancestry and disease susceptibility.
“In most cases the quality is almost equivalent to if you took a sample from a person,” says Duffy.
While there could be uses for this – like helping with finding missing people, or monitoring population health, the researchers point out in their paper that there are serious ethical concerns.
These include a lack of consent from people to have their DNA recorded, privacy breaches, and risks that their genetic information might be used for malicious or commercial reasons.
This is particularly problematic for eDNA, because the field depends upon open and easily accessible data.
“It’s standard in science to make these sequences publicly available. But that also means if you don’t screen out human information, anyone can come along and harvest this information,” says Duffy.
“That raises issues around consent. Do you need to get consent to take those samples? Or institute some controls to remove human information?”
The researchers say in their paper that stakeholders should “immediately” start planning regulations around human information in eDNA.
“Any time we make a technological advance, there are beneficial things that the technology can be used for and concerning things that the technology can be used for. It’s no different here,” says Duffy.
“These are issues we are trying to raise early so policy makers and society have time to develop regulations.”