The study of human genetics can lead to amazing discoveries that can better our lives. By learning how DNA and genomes work, experts can create blueprints that explain the vast complexities of the human body, what makes it work, and what makes it not work. Sequencing genomes can provide insight as to what is currently going on in your body, and what may eventually happen in the future. Through DNA tests and genome sequencing, markers for life threatening conditions can be identified, allowing treatment options to be planned efficiently.
And while being able to map someone’s genome today may prove to be vitally important, it is equally important to understand the genomes of our ancestors. On Monday, October 3, 2022, Swedish geneticist Svante Pääbo was honored with one of the most prestigious awards, the Nobel Prize in Physiology or Medicine, for his work in sequencing ancient DNA.
Alfred Nobel was born in Stockholm, Sweden on October 21, 1833, into a family deeply immersed in the sciences. He passed away from a cerebral hemorrhage at the young age of 63 on December 10, 1896. Throughout his lifetime, Alfred became known as a brilliant chemist, engineer, and inventor. With 355 inventions, most notably dynamite, Alfred amassed an enormous fortune. In Alfred’s final will, he indicated that his fortune should go to the recognition of those who have worked to better the world in the fields of physics, chemistry, physiology or medicine, and peace.
As stated in Alfred’s will, a prize would be awarded to “those who, during the preceding year, have conferred the greatest benefit to humankind.” The Nobel Foundation spent 5 years organizing to fulfill Alfred’s wishes. On December 10, 1901, the first Nobel Prize ceremony was held in Stockholm. Since then 609 Nobel Prizes consisting of a diploma, a gold medal, and 10million SEK have been presented to 975 laureates.
This year, Svante Pääbo has joined more than 20 of the most recognized geneticists in history, including Frederick Sanger who developed the frameworks for modern genome sequencing, as the recipient of the Nobel Prize. Much like Alfred Nobel, Svante was born in Stockholm to a family of scientists. Though he had little presence in Svante’s life, his father, Sune Bergström, also won a Nobel Prize for Physiology or Medicine in 1982. As one of the founders of paleogenetics, Svante has dedicated his research to the sequencing of the Neanderthal genome.
For Svante, studying ancient DNA is much like how ancient cultures are studied to understand how modern cultures have come to be. “Just as you do an archeological excavation to find out about the past, we sort of make excavations in the human genome,” Svante said. However, Svante’s discoveries can lead to vital insight into how the human immune system developed. In the wake of the global coronavirus pandemic, this type of knowledge has become more important than ever.
Scientists know that around 800,000 years ago, there was a divergence between Neanderthals and Homo sapiens. By extracting DNA samples from ancient bones, Svante became the first to sequence Neanderthal mitochondrial DNA in 1997. In 2006, towards the end of the landmark Human Genome Project, Svante announced his goal of fully sequencing the Neanderthal genome. Using a small finger bone found in a Siberian cave, Svante set out to complete the full genomic sequencing.
What he found after comparing more than 3 billion base pairs, was truly remarkable. As explained by 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.” Before this discovery, it was known that people living outside of Africa share 1-2% of their genes with Neanderthals, a group of people with no known presence within the continent.
However, with Svante’s discovery of a group he termed Denisovans, he was able to see that there was intermingling and procreation between Neanderthals and Homo sapiens that led to specific genomic immune markers. These gene markers from Denisovans have since been found in 6% of people living in Asia and Southeast Asia as well. “By mixing with them after migrating out of Africa,” Anna stated, “Homo sapiens picked up sequences that improved their chances to survive in their new environments.”
During the pandemic, Svante once again looked at how the evolution of Neanderthal and Denisovan genomes impacts immunity. He discovered that populations that share European Neanderthal DNA would be subject to higher COVID-19 complications. “The greatest risk factor to become severely ill and even die when you’re infected with the virus has come over to modern people from Neanderthals,” Svante said. “So we and others are now intensely studying the Neanderthal version versus the protective modern version to try to understand what the functional difference would be.”
Svante’s research, the ability to extract and preserve useable DNA from limited ancient sources, will go on to have an impact on how we understand modern immunity. This knowledge will allow experts to develop resistance protocols that will protect people from illnesses like the coronavirus. As stated by the Nobel Committee, their motivation behind awarding Svante the Noble Prize in Physiology or Medicine was in recognition “for his discoveries concerning the genomes of extinct hominins and human evolution.” These discoveries will go on to have a lasting impact on the betterment of humankind, aligning perfectly with Alfred Nobel’s last will.