Swedish scientist Svante Paabo won the Nobel Prize in medicine Monday for his discoveries on human evolution that provided key insights into our immune system and what makes us unique compared with our extinct cousins, the award's panel said.
Paabo has spearheaded the development of new techniques that allowed researchers to compare the genome of modern humans and that of other hominins — the Neanderthals and Denisovans.
While Neanderthal bones were first discovered in the mid-19th century, only by unlocking their DNA — often referred to as the code of life — have scientists been able to fully understand the links between species.
This included the time when modern humans and Neanderthals diverged as a species, determined to be around 800,000 years ago, said Anna Wedell, chair of the Nobel Committee.
"Paabo and his team also surprisingly found that gene flow had occurred from Neanderthals to Homo sapiens, demonstrating that they had children together during periods of co-existence," she said.
This transfer of genes between hominin species affects how the immune system of modern humans reacts to infections, such as the coronavirus. People outside Africa have 1-2% of Neanderthal genes.
Paabo and his team also managed to extract DNA from a tiny finger bone found in a cave in Siberia, leading to the recognition of a new species of ancient humans they called Denisovans.
Wedell described this as "a sensational discovery" that subsequently showed Neanderthals and Denisovan to be sister groups which split from each other around 600,000 years ago. Denisovan genes have been found in up to 6% of modern humans in Asia and Southeast Asia, indicating that interbreeding occurred there too.
"By mixing with them after migrating out of Africa, homo sapiens picked up sequences that improved their chances to survive in their new environments," said Wedell. For example, Tibetans share a gene with Denisovans that helps them adapt to the high altitude.
"Svante Pääbo has discovered the genetic make up of our closest relatives, the Neanderthals and the Denison hominins," Nils-Göran Larsson, a Nobel Assembly member, told the Associated Press after the announcement. "And the small differences between these extinct human forms and us as humans today will provide important insight into our body functions and how our brain has developed and so forth."
Paabo, 67, performed his prizewinning studies in Germany at the University of Munich and at the Max Planck Institute for Evolutionary Anthropology in Leipzig. Paabo is the son of Sune Bergstrom, who won the Nobel prize in medicine in 1982. According to the Nobel Foundation, it's the eighth time that the son or daughter of a Nobel laureate also won a Nobel Prize. Only once has a father-son duo shared the same Nobel Prize: in 1915 when Sir William Henry Bragg and his son William Laurence Bragg won the physics award together.
Scientists in the field lauded the Nobel Committee's choice this year.
David Reich, a geneticist at Harvard Medical School, said he was thrilled the group honored the field of ancient DNA, which he worried might "fall between the cracks."
By recognizing that DNA can be preserved for tens of thousands of years — and developing ways to extract it — Paabo and his team created a completely new way to answer questions about our past, Reich said. That work was the basis for an "explosive growth" of ancient DNA studies in recent decades.
"It's totally reconfigured our understanding of human variation and human history," Reich said, adding that Paabo "was, more than anyone, the pioneer of this field."
The medicine prize kicked off a week of Nobel Prize announcements. It continues Tuesday with the physics prize, with chemistry on Wednesday and literature on Thursday. The 2022 Nobel Peace Prize will be announced on Friday and the economics award on Oct. 10.
Last year's medicine recipients were David Julius and Ardem Patapoutian for their discoveries into how the human body perceives temperature and touch.
The prizes carry a cash award of 10 million Swedish kronor (nearly $900,000) and will be handed out on Dec. 10. The money comes from a bequest left by the prize's creator, Swedish inventor Alfred Nobel, who died in 1895.
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