A geneticist whose techniques for probing ancient DNA have opened a rich window onto human evolution has won the 2022 Nobel Prize in Physiology or Medicine.
Svante Paabo, a native of Sweden, is the founder and director of the department of genetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany. He was announced the sole winner of this year’s medical Nobel on Monday morning.
Dr. Paabo’s contributions include the first sequencing of the Neanderthal genome using DNA extracted from bone. The achievement showed that the Ice Age species first diverged from Homo sapiens some 800,000 years ago.
The research led to revelations that modern humans of non-African origin derive a few per cent of their DNA from Neanderthals – proof that mixing between the species occurred at more recent points after the human family tree diverged. The last Neanderthals are thought to have died out in Europe about 40,000 years ago based on a recent radiocarbon analysis of specimens.
In a separate series of investigations, Dr. Paabo and his team discovered the existence of another closely related human species, known as the Denisovans. Unlike Neanderthals, for which ample fossil evidence exists, the Denisovans were found entirely through their DNA, first recovered from a finger bone from a cave in southern Siberia. It’s now estimated that populations in Southeast Asia carry up to 6 per cent of Denisovan DNA in their genomes, also acquired many thousands of years ago through interbreeding between Homo sapiens and the now-extinct relative.
The genetic sequences obtained in this way are thought to have persisted because they helped Homo sapiens adjust to new and colder environments after they first began spreading out from Africa as early as 90,000 years ago.
“Svante Paabo’s groundbreaking discoveries allow us to address one of the most fundamental questions of all: What makes us unique?” said Anna Wedell, a professor of medical genetics at the Karolinska Institute in Stockholm and a Nobel committee member, at Monday’s announcement.
Following the announcement, committee members also noted how Dr. Paabo’s work had helped to shed light on the story of human migration around the planet.
“It’s incredible news. I am so happy for him,” said Hendrik Poinar, a professor at McMaster University in Hamilton who is known for his work in DNA recovery from both historic and prehistoric remains, and who earned his PhD in Dr. Paabo’s lab in the 1990s.
“Svante was a pleasure – and a challenge – to work for and to work with,” he added. “But the challenging part has made me the scientist I am today.”
Dr. Poinar added that Dr. Paabo deserves credit not only for his news-making discoveries but also for his rigour and determination in employing the emerging tools of genomics to address some of the deepest questions about humanity’s origins.
“Those very early days were about figuring out what the limits of detection would be, where DNA might actually survive, and how easy it was to get false data in the form of modern human DNA contamination,” Dr. Poinar said.
Dr. Paabo is 67. He was born in Stockholm and grew up with his mother, Karin Paabo, a chemist and Estonian refugee, he told The New Yorker magazine in 2011. His father, biochemist Sune Bergstrom, shared the Nobel prize in medicine in 1982.
He received his PhD from Sweden’s Uppsala University in 1986 for research into how adenoviruses modulate the immune system. His pioneering studies in paleogenomics – the science of ancient genomes – first arose as a side project in the 1990s when he was a researcher at the University of Munich. There he began working with DNA extracted from Neanderthal remains. But it would take years before the tools and techniques were developed to allow him to reconstruct the lost species’ genome – described as a “seemingly impossible task” by the Nobel committee.
Mirjana Roksandic, a researcher who studies Neanderthals and other early humans at the University of Winnipeg, said Dr. Paabo’s work was instrumental in bringing genetics into the realm of archeology and anthropology.
“While his early results were disputed, they opened a new era of research and created a vibrant new field,” she said. “I think it is great that he is recognized with the Nobel Prize.”
This win is something of a departure for a category of Nobel Prize that is best know for honouring discoveries that more closely relate to the treatment of disease. However, the award has also covered more fundamental scientific research. For example, last year Americans David Julius and Ardem Patapoutian won the prize for their discovery of receptors in the human skin that sense temperature and touch.