The 2022 Nobel Prize in Physiology or Medicine was awarded to Prof. Svante Pääbo, Ph.D., for his work on extinct hominin genomes and for his new insights into human evolution. Pääbo is considered the founder of paleogenetics.[1]
Svante Pääbo, Ph.D.
Pääbo conducts research at the Max Planck Institute for Evolutionary Anthropology in Leipzig and at the University of Leipzig, both in Leipzing, Germany. His research also showed, among other things, that archaic gene sequences from our extinct relatives influence the physiology of modern humans.
By examining the genome of Neanderthal man – who was the first to sequence it – and comparing it to that of living humans, “his discoveries lay the foundation for exploring what makes us unique human beings,” according to the jury.
Neanderthal genome sequencing
From the beginning of his career, Pääbo investigated the possibility of using modern genetic methods to study Neanderthal DNA. He soon faced extreme technical difficulties due to the degradation of nucleotide chains over time. During his postdoctoral studies at the University of California, Berkeley, USA, after completing a dissertation in 1986 with Allan Wilson, a pioneer in the field of evolutionary biology, Pääbo began developing methods for studying Neanderthal DNA. a work that spanned several decades.
In 1990 the researcher was hired at the University of Munich in Munich, Germany, where he continued his work on archaic DNA as a newly appointed professor, with a particular interest in Neanderthal mitochondrial DNA. Although the mitochondrial genome is small, containing only a fraction of the cell’s genetic information, it has the advantage of being present in thousands of copies, increasing the chances of success. Thanks to the techniques he developed, Pääbo was able to sequence a region of mitochondrial DNA from a 40,000-year-old bone. Comparisons with modern-day humans and chimpanzees have shown that Neanderthals are a genetically distinct species.
In 1997, the Swedish biologist founded a paleogenetic research center within the Max Planck Institute for Evolutionary Anthropology, where he tackled the sequencing of the genome, not mitochondrial but nuclear, of the Neanderthal thanks to new technical developments that allowed the sequencing of the DNA is very efficient. Pääbo also invited several key collaborators specializing in population genetics. His efforts were crowned with success, because in 2010 the researcher published the first sequence of the Neanderthal genome. Comparative analyzes show that the most recent common ancestor of Neanderthals and Homo sapiens lived around 800,000 years ago.
Neanderthals versus Homo Sapiens
Research has provided evidence that anatomically modern humans, Homo sapiens, emerged in Africa around 300,000 years ago, while our closest known relatives, the Neanderthals, evolved outside of Africa and populated Europe and western Asia from around 400,000 years to 30,000 years ago . when they died out. About 70,000 years ago groups of Homo sapiens migrated from Africa to the Middle East and from there across the rest of the world. Homo sapiens and Neanderthals coexisted across much of Eurasia for tens of thousands of years.
A sensational discovery: Denisova
In 2008, a 40,000-year-old finger bone fragment was discovered in Denisova Cave in southern Siberia. The bone contained exceptionally well-preserved DNA, which Pääbo’s team sequenced. The results caused a stir: the DNA sequence was unique compared to all known Neanderthal and modern human sequences. Pääbo had discovered a previously unknown hominid that was given the name Denisova. Comparisons with sequences from contemporary humans from different parts of the world showed that gene flow also occurred between Denisova and Homo sapiens. This relationship was first observed in populations from Melanesia and other parts of Southeast Asia.
What do the discoveries of Nobel Prize winner Svante Pääbo contribute?
Essentially to better understand the history of our evolution. At least two extinct hominin populations lived in Eurasia at the time Homo sapiens migrated from Africa. Neanderthals lived in western Eurasia, while Denisovans populated the eastern parts of the continent. During their expansion out of Africa and their eastward migration, Homo sapiens encountered and interbred with not only Neanderthals but also Denisovans.
Physiologically, paleogenomic work indicates that archaic genetic sequences influence modern humans. Like the Denisovan version of the EPAS1 gene, which confers a high-altitude survival advantage and is widespread among modern Tibetans. He also found that gene transfer occurred between these now-extinct hominins and Homo sapiens after they migrated from Africa about 70,000 years ago. This ancient flow of genes to modern humans has physiological significance today, for example by influencing how our immune system responds to infections.
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