Eske Willerslev: The pioneer of environmental DNA

Big scientific discoveries sometimes stem from unexpected insights. For  eDNA pioneer Eske Willerslev, it started on an autumn day with a woman and her dog.

In the late 1990s, Willerslev, a cash-strapped master’s student, was stuck. He wasn’t famous enough to get the interesting bone samples normally used to do research on ancient DNA. He needed a new idea –  an available material that would be interesting but no one had thought about studying. That’s when inspiration struck. 

One day, as he looked out the window and saw leaves falling to the ground while a dog was pooping on the street, he had a realization.

 “I thought, there’s DNA in all these things,” he recalls. “The poop, all the leaves—they’re gone after a while, but what happens to the DNA? Could it survive in the soil?”

His hypothesis was daring at the time. No one believed that animal and plant DNA could persist in the environment. Even his supervisor dismissed the idea. 

But Willerslev thought differently. Years spent trekking in Siberia’s permafrost, trapping animals and studying the land, had shown him how well the frozen ground could preserve organic matter.

“If it didn’t work there, it wouldn’t work anywhere,” he said. 

With two grams of soil from Siberia’s permafrost, Willerslev ran the experiment. It was Christmas day when the results came in, and they were more than what he bargained for: DNA from woolly mammoth, bison, reindeer, lemming and hares, plus diverse plants, all extracted from ancient soil. 

“It was the greatest Christmas present,” he says. “That’s when I knew we’d really hit something.”

That discovery – recovering DNA from permafrost – opened much more than a new chapter in science. It wrote an entirely new book. Today, environmental DNA is a revolutionary tool used in the study of present and past ecosystems, conservation biology, as well as monitoring biodiversity and tracking diseases. Much of that success is thanks to Willerslev’s skills in asking big questions and travelling to every corner of the world to find answers.

Celebrating a pioneer in science

The Villum Kann Rasmussen Annual Award in Science and Technology, given on Villum Kann Rasmussen’s birthday since 1987, honours those whose groundbreaking work answers fundamental questions and redefines their fields.

“Eske is a hunter of genetic information whose talent lies in seeing the significance of the insignificant,” says Thomas Bjørnholm, Chief Scientific Officer at Villum Foundation. 

Willerslev’s contributions to ancient DNA studies both in the fields of ancient environmental DNA and ancient human DNA have revolutionized how scientists understand the past. His discoveries include the tracking of migration routes of indigenous peoples, reconstruction of ancient ecosystems, and revealing how genetic history shapes modern diseases. Bjørnholm says that Willerslev’s scientific excellence and profound curiosity about humanity’s origins exemplifies the spirit of the award.

“He opened a history book that rewrites our understanding of the past,” he says.

The power of showing up

Willerslev’s path to scientific success didn’t begin in a lab or a classroom. It started in the wild. At 18, he and his twin brother spent months living in Siberia trapping animals and braving subzero temperatures. That experience, he says, shaped his approach to research. 

“My early adventures taught me the importance of being there,” he says. “Many researchers don’t go out to take samples themselves. They contact museums and never experience the regions or landscapes where the samples come from. When I’ve been out in the wind, rain, and snow, I connect the data to something real.”

This ethos has driven Willerslev to travel to some of the world’s most remote places, which has proven valuable for both his studies in environmental DNA and his studies on human genomics. He has collaborated with Indigenous groups in several places, including Siberia, Greenland, North America, and Australia.  

“Eske is not a ‘stay-at-home’ scientist. One of his greatest and most important contributions is developing relationships with native communities. Eske will, almost literally at the drop of a hat, fly across the world to go out to a reservation and talk to people about the work he’s doing,” says David Meltzer, Willerslev’s longstanding collaborator and a professor at Southern Methodist University in Dallas, US.

A rocky road to recognition

But Eske Willerslev’s revolutionary finding of environmental DNA didn’t gain traction overnight.

“The first 10 years, no one really paid attention,” Willerslev says. “I was the only one pushing the field, and it was very hard. I had to fight to get the results published.”

Scepticism stemmed from the concept’s novelty, he says. Reviewers questioned where the DNA came from, whether it could survive in soil, and why anyone would use it instead of pollen. For Willerslev, this was a frustrating yet inevitable part of breaking new ground.

“Of course, you don’t know everything when you’re doing something new,” he says. “That’s the point—to figure it out.”

The tide began to turn when highly respected biologist Pierre Taberlet joined forces with Willerslev, lending credibility to the emerging field. Together, they coined the term “Environmental DNA,” giving the discipline both a name and a rallying point.  A decade later, the field of eDNA had exploded, revolutionizing biodiversity monitoring, conservation, and climate research.

Big Questions. Big Discoveries.

Willerslev thrives at the intersection of curiosity and adventure. 

“I like big stories,” he says. “I like when the data addresses fundamental questions that have been debated for a long time.”

And his work has consistently done just that. 

Willerslev now leads the Centre of excellence in Ancient Environmental Genomics (CAEG) which aims to use ancient environmental genomics to improve our understanding of ecological and evolutionary processes across great distances of space and time, and he leads the Ancient Environmental Genomics Initiative for Sustainability (AEGIS) aiming to harness ancient environmental DNA to develop climate-resilient crops and sustainable agroecosystems. 

By analysing genetic material from sediment cores, Willerslev and his team hope to understand how past ecosystems and species adapted to climatic changes. Insights from this research could inform contemporary agricultural practices and enhance global food security.

Transforming science – and society

Today, environmental DNA is used to monitor endangered species, track invasive populations, and predict ecosystem changes. For Willerslev, the societal applications of his research have become increasingly important. 

“I used to think that being a scientist was all about basic research—learning about the world,” he says. “But now, I also want to see if we can apply this knowledge to address real issues, like food security. That’s where I hope these discoveries will make a difference.”

Looking back, Willerslev says he is proudest of his work with environmental DNA because of how it has redefined what’s possible. 

“It fundamentally changed how we think about DNA, where it’s found, and how we use it,” he says. “It’s a legacy I’m deeply proud of, and I hope it will continue to make a difference for humanity.”

Find out more about the Villum Kann Rasmussen Annual Award