Svante Pääbo receives the Nobel Prize in Physiology or Medicine

Geneticist Svante Pääbo received a Nobel Prize for his work on evolutionary genetics

By Carissa Wong

The 2022 Nobel Prize in physiology or medicine was awarded to Svante Pääbo for his discoveries on man evolution and the genomes of our departed human relatives.

In 1990, Pääbo – who founded the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany – pioneered methods of sequencing ancient DNA by attempting to sequence that of Neanderthal mitochondria, the powerhouses of cells. He achieved this by using a bone from a Neanderthal who lived 40,000 years ago.

DNA degrades and can be contaminated, meaning that ancient DNA sequencing was considered impossible.

“Humanity has always been intrigued by its origins,” said Anna Wedel, chairman of the Nobel Committee for Physiology or Medicine, when announcing the prize on October 3. “Where do we come from? And how are we related to those who came before us? What differentiates us from the hominids that have disappeared?

“Pääbo has finally reached the [what was thought to be] impossible sequencing and assembly of the Neanderthal genome…and discovered a whole new hominid entirely [the Denisovans] by analyzing and comparing genome sequences,” she said.

Mitochondrial DNA contains very limited information about an individual’s overall physiology, so Pääbo then sequenced ancient DNA packaged into the nucleus, or master control center, of ancient cells.

Using three Neanderthal bone specimens from Vindija Cave in Croatia, along with others from Germany, Russia and Spain, Pääbo sequenced the 3 billion base pairs of the Neanderthal genome.

By comparing the Neanderthal genome with that of Homo sapiensPääbo revealed that these hominid groups diverged around 400,000 to 800,000 years ago and would have reproduced in western Eurasia after H. sapiens migrated out of Africa about 70,000 years ago.

As a result, up to 2% of the genome of people of European or Asian descent comes from Neanderthals, including genes that affect our immune response at infections.

In 2008, Pääbo sequenced DNA from a 40,000-year-old finger bone discovered in a cave in southern Siberia. By comparing this DNA with that of Neanderthals and H. sapienshe discovered a whole new type of hominid, the Denisovans.

Further analysis revealed that H. sapiens bred with Denisovans in eastern parts of Eurasia. As a result, people in Melanesia (a region of the South Pacific Ocean made up of around 2,000 islands, including New Guinea, Ghoi and Tanna) and parts of Southeast Asia have up to 6% DNA from Denisovan.

Pääbo’s work also supported the discovery that a gene inherited from the Denisovans helps today’s Tibetans survive at high altitudes with low oxygen concentrations.

“There are a lot of implications [to Pääbo’s research]both in terms of understanding our evolution, potential medical implications and a basic understanding of our physiology,” said Gunilla Karlsson-Hedestammember of the Nobel committee, during the announcement.

Studying ancient DNA will continue to reveal the genetic basis for other aspects of our physiology and, in doing so, contribute to medical advances, she said.

Referring to when Pääbo was told of his Nobel Prize success, Thomas Perlmann, Secretary of the Nobel Assembly, said during the announcement: “He was speechless, very happy.”