Friday, December 8

Who can analyze the DNA that we are losing out there?

Our body is releasing biological material and leaving a trail of DNA in its wake. And this material can be obtained and analyzed by scientists who collect ‘environmental DNA’ without prior authorization and without the procedure having been well regulated by research ethics committees.

Reasons not to take a DNA test online (or to do it)


This is the main conclusion that emerges from a study carried out by David Duffy and his team at the University of Florida, which is published this Monday. in the magazine Nature Ecology & Evolution. “We have been constantly surprised throughout this project by the amount of human DNA we found and the quality of that DNA,” says the researcher. “In most cases, the quality is almost equivalent to taking a sample from a person.”

The analysis of the so-called ‘environmental DNA’ is one of the most active fields of study within genetics. The collection and screening of sediments has recently allowed, for example, the reconstruction of an ecosystem from about two million years ago in Greenland, and in other parts of the world scientists collect samples to study biodiversity, monitor invasive species or analyze the presence of pathogens, as is done with wastewater.

What happens when human DNA appears in these samples obtained in nature? Until now, the issue was not relevant because scientists sifted through genetic information in search of specific species, but David Duffy’s team has just discovered a possible avenue of ethical and privacy conflicts that no one had emphasized.


While analyzing environmental DNA collected in their study of the green turtles (Chelonia mydas), Duffy thought it would be useful to analyze all the possible species that lived around them, in addition to viruses and bacteria. “Logically, we expected to obtain a small amount of human DNA, but we expected to find much more in the sea turtle tanks at our facilities than in the water samples taken from the environment (rivers and marshes),” he explained to “But when the results came back, we realized that our environmental samples had much more human DNA than those taken from our turtle tanks.”

The authors found human genetic material in all kinds of landscapes, from oceans to mountains.

After the accidental discovery, the researchers decided to continue collecting and searching for human DNA in the samples they took in the following six years of research, with the mandatory approval of the ethics committee of the university. “And as we continue to recover human DNA from a wide range of locations, we know that other ‘environmental DNA’ studies must also be inadvertently capturing human DNA,” he says.

The authors found human genetic material in all types of landscapes, from oceans to mountains, only discovering uncontaminated places in very remote areas such as the beach of an uninhabited island. There they took the opportunity to carry out an experiment with volunteers, who walked through the sand and the team was able to obtain identifiable DNA from their footprints. They also repeated the experiment by capturing the air of occupied and unoccupied rooms, in which they subsequently identified DNA from the people who had been present.

“We wanted to test the quality of the human DNA recovered from the environment (water, sand, and air) and what it could tell us about the humans from whom the DNA originated,” he says. “We wanted to better understand how many ethical concerns can arise from ‘environmental DNA’ sampling.” What they conclude in his work is that this accidental capture of human genetic material raises ethical and privacy concerns that are not necessarily subject to the strict scrutiny faced by other forms of research that collect identifiable information about individual humans. What worries them, they say, is that potentially large volumes of human DNA, including enough data to identify and phenotype individuals, will soon be recovered. And “obtaining genetic data from identifiable persons requires informed consent,” they recall.

new ethical frontier

“To be honest, I never thought about the ethical ramifications of this,” admits geneticist Tomás Marqués Bonet, an ICREA researcher and professor at Pompeu Fabra University, who has not participated in this study but has collected environmental DNA in his own investigations. on chimpanzee populations, although he has always dismissed this material without analysis. In his opinion, this work opens up a very interesting perspective that should be taken into account in the future. “They open a new frontier for us: what to do with the human data that is collected incidentally when environmental DNA is measured? As at other times in the history of genetics, the technique surprises us with new acquisitions that must be complemented with a pertinent regulation so that its use adapts to what society requires of us. An ethical and responsible use of our genetic legacy ”, he explains to

They open a new frontier for us: what to do with human data that is collected incidentally when environmental DNA is measured?

Thomas Marquis Bonet
UPF professor

The professor of genetics at the University of Barcelona, ​​Gemma Marfany, finds these results surprising and of the utmost interest. “What they tell you is that it is something that no one had thought of up to now and that it has to be regulated,” she says. In her opinion, the main concern is that some of this raw data is uploaded to public repositories, thus losing control of the use that can be made of it. The advantage of environmental DNA, she points out, is that because it’s mixed you can’t assign it to people, unless there are very specific circumstances. “But it raises many questions about the use that can be given at the population or group level,” she says.

Marfany recalls the case of the Havasupai tribe, in northern Arizona, who won a lawsuit against the authorities for having used genetic material from some of its members to study the health of the ethnic group without prior consent. “They have never given it and that contravenes their culture,” he explains. “They were using population data for purposes for which they had not been given permission.”

Human environmental DNA could be used for surveillance of individuals or minority groups such as uncontacted tribes

Human environmental DNA applications, the study authors explicitly point out, “could be used for surveillance of individuals, minority groups (genetic ancestry) or genetic disabilities, or to obtain genomic information from local populations without their knowledge or consent, including indigenous peoples.” genetically diverse ‘valuables’ (uncontacted tribes, particular ethnic groups, etc.)”. These scenarios, they point out, amplify the current problems related to the commodification of genomic information.

The most perverse uses of DNA

Taken to the most negative extreme, the authors fear that this DNA captured from the environment could be used to determine whether members of a genetically distinct group were present in a given population. Wastewater or air filtration could be monitored in urban areas or in private homes, for example. “That potential is particularly chilling given the propensity of humans to carry out ethnic persecution and genocide throughout our history,” they stress.

“Documented human rights abuses have already occurred through the use of national DNA databases in China with other surveillance data to monitor minority populations,” explains Jessica Farrell, co-author of the study, referring to the persecution of the uyghur minority. “This was not done with environmental DNA, but in the future the technology could be applied in a similar way.”

The geneticist Gemma Marfany points out other threats of perverse use of genetic information, such as the campaign that was carried out in the city of Hong Kong a few years ago, where the possible anatomical appearance of the owners of the garbage was reconstructed from DNA. thrown in the streets to mark them as bad citizens. “Forensic laboratories already work with these ideas and some companies, such as Parabon nanolabs, offer an inference of the person’s traits from their DNA”, he points out. “They take your face and turn it into a dot matrix, all they have to do is genetic correlations. And this is something that is going to be on the table”.

Safety measures

Without going as far as the singer Madonna, whose team sterilizes the dressing room after her performances so that no one can get genetic material from the star, Farrell believes that “in the future we will have to be aware of the genetic material we leave behind.” . But the good part, he adds, is that “with proper regulation, we should be able to prevent the misuse of this scattered DNA.”

It is time for lawmakers and scientific communities to take these problems seriously, say the authors

This result is a wake-up call on an issue that can present unexpected variants and privacy vulnerabilities that we had not considered. Now that it’s clear that human DNA can be easily sampled from the environment, the paper’s authors believe it’s time policymakers and scientific communities take consent and privacy issues seriously and balance them with potential benefits of studying this DNA dispersed in nature.

“Any time we make a technological breakthrough, there are beneficial things that technology can be used for and worrisome things that technology can be used for. It’s no different here,” Duffy concludes. “These are issues that we are trying to raise early so that lawmakers and society have time to develop regulations.”