The 2022 Nobel Prize for Physiology or Medicine has been awarded to Swedish geneticist Svante Pääbo for his groundbreaking research in paleogenomics, specifically focused on the genomes of extinct hominins and human evolution. This follows the 2021 awarding of this prestigious honour to David Julius and Ardem Patapoutian, U.S.-based scientists recognized for their discoveries of receptors for temperature and touch.
Pivotal Research Discoveries by Svante Paabo
Pääbo’s research has yielded vital insights into human evolution, particularly our closest known relatives — the Neanderthals and Denisovans. Homo sapiens first appeared in Africa approximately 300,000 years ago, while Neanderthals developed outside Africa and populated Europe and Western Asia for around 400,000 years until they went extinct about 30,000 years ago.
Decoding the Genome Sequencing of Neanderthals
Sequencing of Neanderthal genes revealed that sequences from our extinct relatives significantly impact the physiology of present-day humans. One example is the Denisovan version of the EPAS1 gene, which provides a survival advantage at high altitudes and is prevalent among modern Tibetans. Other influences include Neanderthal genes affecting our immune response to various infections.
Discovery of Denisova and Coexistence of Human Species
In 2008, the discovery of a 40,000-year-old finger bone fragment in Siberia’s Denisova cave led to the identification of an unknown hominin, named Denisova. Intriguingly, the ancestors of modern humans co-existed with Neanderthals and Denisovans for about 20,000 years, an era characterized by significant interaction and interbreeding. This shared history is evident in present-day humans of European or Asian descent, who possess approximately 1-4% genome originating from Neanderthals. Additional gene flow also occurred between Denisova and Homo sapiens.
Innovative Methodology and its Significance
The process of amplifying and sequencing ancient DNA is a challenging task due to it being highly fragmented and rife with microbial contamination. To counter this, Pääbo chose to examine mitochondrial DNA from Neanderthals, present in thousands of copies within the cell, thereby enhancing the likelihood of successful sequencing. This breakthrough methodology holds immense significance in understanding human evolution. Consequently, Pääbo’s work has spurred the rise of paleogenomics — the study and analysis of genes from ancient or extinct organisms.
The Legacy of Neanderthals
Neanderthals, the closest known relatives to present-day humans, inhabited regions spanning Europe and West Asia to southern Siberia and the Middle East before their extinction approximately 30,000 years ago.
Demystifying Denisovans
Denisovans, another extinct hominid species, were closely related to Neanderthals and resided in Asia. Researchers have unearthed significant evidence, such as an adult tooth and well-preserved finger bone, belonging to this early human species. Subsequent genome analysis suggested that the individual, a young girl between five and seven years old when she died, was a distinct species named “Denisovan”. Further research suggested that Denisovans had brown hair, eyes, and skin.
Last Modified: February 18, 2024