In recognition of his work discovering and sequencing the genomes of extinct hominins, Svante Pääbo is given the 2022 Nobel Prize in Physiology or Medicine by the Nobel Assembly at Karolinska University. He is the founding director of the Department of Genetics at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and a professor at the Okinawa Institute of Science and Technology in Okinawa, Japan. In groundbreaking work, Svante Pääbo sequenced the genome of the Neanderthals, who are presumed to be our distant ancestors. This provided answers to many of the unanswered questions that had been lingering in the field of evolution for a long time. Also, he uncovered the existence of Denisova, a hitherto undiscovered hominin. More crucially, Pääbo provided proof that genes were exchanged between the newly discovered species and Homo sapiens, the modern human species. Some of our physiological traits, including our immune system, were altered as a direct result of this gene transfer.
It’s no secret that scientists have struggled to answer questions regarding our family tree. It’s something most of us are curious about: our origins, how we’re connected to the people who came before us, and how we evolved into what we now call homo sapiens. Paleontological and archeological findings from discovered bones and artifacts provided much of the knowledge we knew before Pääbo’s studies. Based on these findings, we knew that Homo sapiens first appeared in Africa around 300,000 years ago, whereas our closest relatives, the Neanderthals, first appeared in Europe and Asia around 400,000 years ago. Bone and artifact analyses can tell us that these hominins went extinct about 30,000 years ago, but they cannot tell us how closely connected we are to them.
Relationship Between Neanderthals And Contemporary Humans
Each and every one of a person’s cells have DNA, which contains the genetic blueprint for that person’s entire body. The nucleus of the cell stores the vast majority of this substance, but the mitochondria store a small quantity as well. Half of a person’s DNA is passed on to their kids during each reproduction. Thus, it is possible to use a person’s DNA to learn about their family tree.
Pääbo’s first of many groundbreaking discoveries came as he sought out fresh approaches to studying the DNA of the extinct species we now consider to be our closest cousins. The problem was that, after a million years or more, the DNA started deteriorating, leaving behind only tiny fragments that were too tainted by bacteria and modern human DNA to be studied with conventional genetic methods.
Pääbo spent nearly three decades figuring out how to study the DNA from the fossils of extinct species. To finally make a genetic comparison between Neanderthals and modern people, he began by analyzing mitochondrial DNA from a bone that was 40,000 years old. Although he was unable to identify evidence of genetic similarity among Neanderthal, human, and chimpanzee mitochondrial DNA, he did establish the feasibility of DNA sequencing from such ancient objects. He then repeated the process with the genome from the nucleus, which contains significantly more information than mitochondrial DNA. He collected three bone samples from different parts of the world to use in perfecting his method for sequencing the nucleus genome. Through a comparison of genomes, Pääbo and a vast group of researchers found that Neanderthals were closely linked to people from Eurasia, raising the possibility that they interbred throughout their coexistence.
Discovery Of A New Hominin, Denisova
Simultaneously, Pääbo studied a finger bone that dated back 40 thousand years and was discovered in the Denisova cave in southern Siberia. The findings of Pääbo and his colleagues shocked the scientific world. Unknown DNA was uncovered that was incomparable to that of either modern humans or Neanderthals. Denisova is the name Pääbo gave to the newly discovered species of hominid, and he found that we also share a small part of our DNA with theirs.
A New Field Of Study, Paleogenomics
With this groundbreaking work, Svante Pääbo paved the way for the development of paleogenomics, a rapidly growing academic subfield. The field of paleogenomics focuses on reconstructing and analyzing the genomes of extinct species. Homo sapiens originated in Africa, but Neanderthals and Denisovans inhabited different regions of Europe and Asia and adapted to those regions. Through these findings, Pääbo deduced that Homo sapiens migrated from Africa to Europe and Asia, where they bred with natives there to expand their genetic diversity and thus their chances of survival. It has also been discovered that 1–2% of the DNA of people from Eurasia originates from Neandertals and 1–6% of the DNA of people from Asia from the Denisovans.
Many Neanderthal and Denisovan people’s genome sequences have been compiled. Many scientists have also amassed sequences from Homo sapien populations from various times and places throughout history. By analyzing these patterns through time and making comparisons, we can learn about our origins, migrations, and cultural influences across the globe. Also, we can learn how we stand apart from these extinct species. This revealed not just our common ancestry with these species but also our unique ancestry that the Neanderthals and Denisovans lacked. The implications for understanding how humans evolved are profound.
This new information explains why some geographical populations are naturally resistant to a variety of diseases. Even though we only have a small sample of DNA from these ancient species, it may have a significant effect on human disorders from schizophrenia to COVID-19, which might signify a big advance for modern medicine.
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