The human DNA is all over the planet.

And scientists are concerned.

Photo by Sangharsh Lohakare on Unsplash

All of your body’s components — skinflakes, hair follicles, eyelashes, and spit drops — are individually programmed with instructions encoded in a chemical code.

A recent study found that technological advancements have made it feasible to extract fragments of human DNA from the air, water, or soil and decode personal information about the people who dropped them.

As helpful as this may appear, the study’s authors caution that society may be unprepared for the consequences.

“Any time we make a technological advance, there are both beneficial and concerning things that the technology can be used for,” says University of Florida zoologist David Duffy, who led a project that tested the limits of sequencing human DNA from environmental samples.

“These are issues we are trying to raise early so policy makers and society have time to develop regulations.”

The Earth’s surface is covered in wasted plant and animal cells, as well as dissolved microorganisms, which release what experts call environmental or ‘e’ DNA.

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Furthermore, representative genetic samples can provide insights that no other procedure can, such as telling researchers about disease prevalence or population linkages.

This is all fine when zoologists are extracting long-lost DNA from ancient silt or looking for evidence of a mythical monster in Loch Ness.

However, strands of material left by passing humans are almost certain to be present in that genetic soup. Unlike Nessie, people get a little funny about who snoops on their genetic secrets.

Photo by National Cancer Institute on Unsplash

While earlier methods of sequencing have struggled to uncover relevant human genetic sequences inside eDNA samples, a process known as shotgun sequencing isn’t quite as constrained, as proved by Duffy and his team conducted their recent investigation.

The researchers gathered water and sand samples near the Whitney Laboratory for Marine Bioscience and Sea Turtle Hospital at the University of Florida, as well as from the environs of a river in Duffy’s native Ireland.

They collected samples from a distant island and a mountain stream far from human settlements.Known as human genomic bycatch (HGB), several chromosomal fragments found with the shotgun approach contained identifying information about their origin.

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Only the island and a remote stream lacked human DNA, although footprints in the sand of the isolated island revealed evidence of the research team’s own genes.

Air samples from the university’s sea turtle hospital also included eDNA, which may be linked to workers, animals, and common animal infections.

“We’ve been consistently surprised throughout this project at how much human DNA we find and the quality of that DNA,” Duffy tells me. “In most cases the quality is almost equivalent to if you took a sample from a person.”

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It’s simple to imagine how such extremely comprehensive genetic assays with HGB could be used in epidemiology or population genetics. However, the sources of the identifiable DNA in this experiment all agreed to participate in the study, which is consistent with the ethics of published genetic research.

“It is customary in science to make these sequences publicly available. However, it also denotes “If you don’t screen out human information, anyone can come in and harvest it,” adds Duffy.

“That raises questions about consent. Do you require permission to take those samples? Or implement certain safeguards to protect personal data?”

As a forensics tool, the benefits are somewhat contradictory, as they expand techniques for tracing individuals to a crime scene.

However, given the CSI effect, which allows a Hollywood-influenced judiciary to easily misinterpret DNA testing results, the legal implications of HGB identification have yet to be properly investigated.

Thank you for reading.