The story of Svante Papu, a Nobel Prize-winning DNA hunter in medicine to achieve the seemingly impossible

(CNN) – Swedish geneticist Svante Pääbo has won the Nobel Prize in Medicine for pioneering the use of ancient DNA to unlock the secrets of human evolution.

The Nobel Committee said on Monday that Papo had “achieved something that seemed impossible” when he sequenced the first Neanderthal genome and revealed that Homo sapiens interbred with Neanderthals.

Its discovery was announced in 2010, after Pääbo pioneered methods for extracting, sequencing and analyzing ancient DNA from Neanderthal bones. Thanks to their work, the scientists can compare the genomes of Neanderthals with the genetic records of humans living today.

“Babo’s basic research led to the emergence of an entirely new scientific discipline: paleobiology,” the committee said. “By revealing the genetic differences that distinguish all living humans from extinct hominins, their discoveries provide the basis for exploring what makes us uniquely human.”

What does Papu’s discovery mean?

Pääbo found that most humans today share between 1% and 4% of their DNA with Neanderthals, which means that Neanderthals and Homo sapiens must have met and had children before the extinction of Neanderthals about 40,000 years ago.

Since 1997, he has been Director of the Max Planck Institute for Evolutionary Anthropology in Leipzig (Germany) and Research Emeritus at the Natural History Museum in London.

“His greatest contribution is his leadership in restoring ancient DNA, and that has been very important in the study of human evolution,” Chris Stringer, the museum’s head of human evolution research, told CNN Monday.

Pääbo’s subsequent work to extract DNA from tiny fossil fragments found in a Siberian cave revealed an equally exciting discovery.

The genome he sequenced showed an extinct species of humans not completely known at the time, which was named Denisovan after the cave. By comparing Denisovan DNA with the genetic records of modern humans, Pääbo showed that some populations in Asia and Melanesia inherited up to 6% of their DNA. Who is this mysterious ancient human?.

How does the DNA you found differ from that of Homo sapiens?

“I think the Neanderthal genome was his biggest contribution. It revealed that Neanderthals interbred with us. This has been discussed for many years, even on my part. But it showed that most of us had ancient DNA (from Neanderthals and/or Denisovans).” Stringer added. About the Nobel Prize in Medicine.

Some of the genetic traces left by the encounters with these two ancient humans are of medical importance today. For example, a Denisovan version of a gene called EPAS1, which confers a high altitude survival advantage and is common among modern Tibetans. Pääbo also found that Neanderthal DNA may play a small role in the evolution of COVID-19 infection.

“This is an important scientific discovery in evolutionary biology,” said David Patterson, professor at Oxford University and president of the UK Physiological Society.

“Attributing physiological function to highly conserved mitochondrial genes has been critical to our understanding of high-altitude adaptation as populations move and adapt to new environments, and how genetic variants affect us in everyday life.” health and disease,” Patterson said in a statement.

Babu’s father, biochemist Sonn Bergstrom, He was part of the 1982 Nobel Prize-winning medicine trio..

An early passion that ended with the Nobel Prize in medicine

When he released his results, Babu “Having a first copy of the Neanderthal genome fulfills a long-standing dream,” he said.

However, his childhood passion was Egyptology, after he visited Egypt with his mother, according to a 2008 interview. One of his early successes was when he succeeded in extracting, cloning and sequencing the DNA of an Egyptian mummy, a job he did secretly at night. While doing research unrelated to the Ph.D.

It took Pääbo decades to perfect the process of extracting DNA from ancient fossils, because over time the DNA is chemically modified and degrades into short fragments. This only leaves traces that could easily be contaminated with actual DNA from bacteria and from human handling of the fossils.

His DNA extraction methods have also been applied to the bones of long-extinct animals, revealing insights into the lives of mammoths, cave bears, giant sloths, and many other creatures. His team is working on techniques to extract DNA from cave deposits, which would allow scientists to identify our closest relatives without having to find their bones: just through dirt in the caves where they spent time.

Katerina Duka, an assistant professor of archaeology at the University of Vienna who is collaborating with Pääbo, told CNN that her work on ancient DNA was as revolutionary in archaeology as the advent of radiocarbon dating, which won him the Nobel Prize in 1960.

“He invented the field. He revealed many secrets about human evolution,” Duca added.