Pääbo, Svante << PAH boh, SVANT ah >> (1955-…), a Swedish biologist, won the 2022 Nobel Prize for physiology or medicine. Pääbo was awarded the prize for his work studying the genes of prehistoric people and other prehistoric animals. A gene is the part of a cell that determines which traits an organism inherits from its parents. The study of prehistoric genes is called paleogenetics. Pääbo has developed techniques to extract and study genetic material from preserved skin, feces (solid body wastes), and fossilized teeth and bones. With these techniques, scientists can examine how once-living organisms relate to one another and to organisms alive today.
Genes are encoded in the structure of a material called DNA (deoxyribonucleic acid). Scientists work with DNA to sequence (determine the order of) the genes. In the 1980’s, scientists discovered that DNA can persist in preserved tissues of ancient organisms—including mummified or fossilized remains—under certain conditions. In his studies, Pääbo has extracted and studied genetic material from the preserved remains of ground sloths, cave bears, woolly mammoths, and other extinct animals.
Pääbo began a project to extract and sequence the entire genome of Neandertals. The term genome refers to all the genes on a cell’s threadlike structures called chromosomes. Neandertals were prehistoric human beings who lived in Europe and Asia from about 150,000 to 39,000 years ago. Many scientists classify Neandertals as an early type of Homo sapiens, the species of modern people. However, other scientists think Neandertals belong in a separate species, Homo neanderthalensis. By comparing the genomes of different species, biologists can determine more accurately how these species are related to one another. So by sequencing the entire Neandertal genome, Pääbo and other scientists hope to learn how Neandertals relate to modern human beings.
In 1997, Pääbo and his team successfully extracted mitochondrial DNA (mtDNA)—a form of DNA found outside the chromosomes in cellular structures called mitochondria—from the upper arm bone of a Neanderthal skeleton discovered in Germany in 1856. It was possible to isolate mtDNA because that form of DNA is hundreds to thousands of times more common in cells than the DNA that makes up chromosomes. He then began work to extract and sequence chromosomal DNA from Neandertal fossils. By 2009, Pääbo announced that his team had sequenced more than 60 percent of the complete Neandertal genome. They sequenced genetic material extracted from a fossil Neandertal bone excavated in Croatia, with additional genetic material from bones excavated in Russia and Spain.
Svante Pääbo was born in Stockholm, Sweden, on April 20, 1955. He studied medicine and molecular immunology at Uppsala University, receiving his Ph.D. degree in cell biology in 1986. Pääbo held positions at the University of Zurich, the University of California at Berkeley, Uppsala University, and the University of Munich in Germany. In 1997, he became director of genetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
In 2010, Pääbo and his colleagues sequenced a genome from fossils discovered by Russian archaeologists at Denisova Cave, on the Anuy River in the Altai Mountains of southern Siberia. The fossil remains included two molar teeth and a single finger bone from a young girl. Analysis of the genome showed the girl was from a previously unknown population of humans. It was the first time scientists had identified a prehistoric human population through DNA analysis alone. They referred to this group as Denisovans.
See also Evolution (DNA studies); Genomics; Neandertals.
