Swedish geneticist wins Nobel Prize in Physiology or Medicine

This year's Nobel Prize in Physiology or Medicine has been awarded to Swedish geneticist Svante Pääbo for his discoveries on human evolution.

Thomas Perlmann, secretary of the Nobel Committee, announced the winner Monday at the Karolinska Institute in Stockholm.

Pääbo has spearheaded research comparing the genome of modern humans and our closest extinct relatives, the Neanderthals and Denisovans, showing that there was mixing between the species.

The prizes carry a cash award of 10 million Swedish kronor (over $1.2 million Cdn) and will be handed out to the winners on Dec. 10. The money comes from a bequest left by the prize's creator, Swedish inventor Alfred Nobel, who died in 1895.

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.

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.

"Pääbo 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. About one to two per cent of people outside Africa have Neanderthal genes.

Wedell described this as "a sensational discovery" that subsequently showed Neanderthals and Denisovan to be sister groups that split from each other around 600,000 years ago. Denisovan genes have been found in up to six per cent 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.

Pääbo, 67, performed his prize-winning studies in Germany at the University of Munich and at the Max Planck Institute for Evolutionary Anthropology in Leipzig. Pääbo is the son of Sune Bergstrom, who won the Nobel Prize in Medicine in 1982.

University of Toronto anthropologist who has worked with Pääbo on Denisovan research:

Pääbo said he was surprised to learn of his win on Monday.