Each year five Nobel prizes are awarded in physiology/medicine, chemistry, physics, literature, and peace to “those who, during the preceding year, have conferred the greatest benefit to society”. Winners of the Nobel prize in medicine or physiology have transformed how we study ourselves and saved lives by developing new medical therapies, uncovering the cause of diseases, advancing new theories, and ushering in revolutionary technologies.
This year the Nobel prize in Medicine was awarded to Svante Pääbo for his pioneering work on ancient DNA – a new way to study life’s history. His discoveries have helped us better define what makes us human and have seismically changed the questions we can ask (and answer) about the past.
Dr. Pääbo is considered the godfather of paleogenetics. This work began as a secret side project during his Ph.D. While studying adenovirus, Dr. Pääbo was given an Egyptian mummy sample and began trying to clone a DNA library from it. Working on this project ignited a passion for working with ancient DNA. Asked about this work Dr. Pääbo said “I’m driven by curiosity, by asking the questions, ‘where do we come from,’ and ‘what were the important events in our history that made us who we are’”.
The work also proved to be devilishly difficult.
Working with 10,000+-year-old DNA poses extreme technical and analytical challenges from both degradation and contamination. Imagine getting a new book (in a foreign language), shredding it, mixing it with your school’s trash, letting it sit in a landfill for a week, and then trying to read it and you’ve got a comparable process! However, the clues and answers that are hidden within ancient DNA are worth the herculean reconstruction effort because they can be found nowhere else.
Through a combination of ingenuity and perseverance, Dr. Pääbo and his team were able to sequence the Neanderthal genome in 2010 from a 40,000-year-old bone sample. A mere 10 years after the modern human genome had been first sequenced! By comparing these two genomes, scientists were able to identify our most ancient and most modern genetic regions. They were also able to tell a far more detailed story of our species’ own evolutionary history as well as the migration routes and interactions of our ancestors.
Since then Pääbo has continued to tackle the numerous, unique, and often baffling challenges of working with aDNA. This work has transformed a type of genetics that was once considered somewhere between impossible and highly suspect into a respected and prolific field. In doing so he’s creating an invaluable set of tools for scientists to examine both our own past and that of other species. For example, it has helped geneticists identify genes that are uniquely human such as a variant link to greater neuronal growth as well as ancient genes that seem to disproportionally influence our risk for diseases like schizophrenia and severe covid-19.
Asked about his colleague’s research and winning the Nobel prize Dr. John Hawks of the University of Wisconsin told the Washington Post, “It matters because our ancestry is what is affecting our health, and when you uncover the genes that we inherited from these distant ancestors that matter to our health, you’re going to open a new window into understanding human disease.”
Dr. Pääbo has used these tools to make several groundbreaking anthropologic discoveries as well. Chief among them was the discovery of a new species closely related to humans called Denisovans from mitochondrial DNA and the discovery of gene flow between neanderthals (Homo neanderthalensis) and humans (Homo sapiens).
Despite the success and scope of his work Dr. Pääbo was still shocked to find out that he had won a Nobel prize. Ask about the call he said, “somehow I did not think that this (work) really would qualify for a Nobel prize.” However, he is following a family tradition – his father Sun Bergstrom won the Nobel prize in medicine in 1982. After finding out, Dr. Pääbo first called his wife to tell her the news and then jumped (and got partially tossed) into the water pool next to his lab!
Learn more about the fantastic field of paleogenetics with our blog post ‘Awesome and Ancient aDNA‘. Or get your own scientists tackling the questions of who we are and where we come from with our Human Origins Experiment.
Title image attribution: Osama Shukir Muhammed Amin FRCP(Glasg), CC BY-SA 4.0