Humans are not 'pure', closeted species - we all carry bits and pieces of DNA from other human beings, at least in small amounts...
A common prejudice is that research into human evolution, excavated skulls, DNA, is only to satisfy human curiosity about origins. But the Nobel Prize on October 3, 2022 gave it a major blow. The Nobel Prize in Physiology or Medicine was announced to Svante Pabo. This time the award is unique, usually given to research that has revolutionized medicine, this year went to Svante Pabo's research on human evolution and the discovery of the genomes of extinct human ancestors.
Mankind has always been curious about our origins. The core of anthropological studies is to find answers to questions like how the human animal originated, what is our relationship with other animals, what exactly is 'human', what is the relationship of different human communities with each other. Fossil remains of Neanderthal humans were discovered in 1856, and soon after Darwin proposed his theory of evolution in 1859, the scientific study of human evolution began. All of this research relies on fossils, stone tools and other remains left behind by humans, whether found by accident or rigorously excavated. Modern anthropology combines three lines of evidence: fossils, stone tools, and the DNA of humans like us who walk the earth today to construct a sequence of human evolution.
Various stages of human evolution in the last seven million years have now come forward from such research. It has now been proven that the humans that look like us, Homo sapiens, evolved in Africa three hundred thousand years ago, and that modern humans spread around the world about 70,000 years ago. One of the most important and famous Neanderthals in this evolutionary journey, however, evolved outside of Africa in Europe and parts of Asia. Neanderthals lived in Europe and Western Asia for about 800,000 to 30,000 years ago. That is, for at least 40,000 years, Neanderthals and Sapiens coexisted in large parts of Europe and Asia.
Why did Neanderthals become extinct 30,000 years ago? For the past 100-150 years, anthropologists and archaeologists have been trying to answer the question of how we, or sapiens, are related to Neanderthals through the study of stone tools, fossils, and human skeletons. Bones alone could not tell unequivocally whether Neanderthal man was our ancestor or just a close relative. After the 1980s and 1990s, DNA sequencing technology became a revolutionary addition to the toolkit for studying human evolution. Using DNA, anthropologists were able to unravel the relationships of contemporary human communities and their spread 'out of Africa to the world'. Although it was known that the relationship between Neanderthal man and sapien man could be solved only with the help of DNA, it seemed impossible that DNA could be obtained from the bones, teeth or other remains of Neanderthal man who became extinct thousands of millions of years ago. Such DNA could only be found in the fictional universe of novels and Hollywood films like Jurassic Park. But Svante Paabo's three decades of research made this impossible possible and gave rise to the science of ancient DNA or ancient genomics. The Nobel Committee has taken notice of this revolutionary research.
After a visit to a museum at the age of thirteen, Pabo was captivated by Egyptology and mummies. Following in his father's footsteps, Pabo completed his medical education, but instead of going into that field, he pursued a Ph.D. at Uppsala University. He decided to do research. While conducting research on viruses and their effects on the immune system, he attended lectures on Egyptology in his spare time. While discussing with the experts, Pabo wondered if it would be possible to get the DNA of the Egyptian mummy and find out what relationship the mummy would have with the Egyptians of today. While working on this PhD research in the laboratory, Pabo was able to extract DNA from parts of Egyptian mummies, and published this research in the scientific journal Nature. He formally began his research work on ancient DNA in 1986 as a post-doctoral fellow in the laboratory of Al Wilson, who introduced the theory from Africa to the world. Polymerase chain reaction (PCR) and DNA sequencing (Sanger DNA sequencing) were recently established techniques that changed the nature of molecular biology. Pabo began research to develop methods for extracting ancient DNA that would make the most of them, and over the next three decades he further developed these methods.
In 1990, Pabo joined the Zoological Institute of the University of Munich as a professor. Identifying the chemical changes that have occurred in obtaining ancient DNA; chemical processes to chemically distinguish the original DNA inside the remains from that of the bacteria, fungi, and researchers handling the remains; the strict care researchers must take in the laboratory to avoid mixing modern DNA with ancient DNA; and the development of laboratory protocols. Pabo and his students researched and validated. Not only that, but also how an ancient DNA lab should be constructed, how researchers should behave in the lab, rules for how the lab should be constantly cleaned with UV rays and other chemicals, and whether the DNA obtained in an ancient DNA lab is actually ancient, not modern DNA mixed by accident. He also researched and established tests to prove this. He did this research on mammoth elephant remains found in glacial regions and bear bones found in abundance in caves. They were also able to obtain DNA from relatively recent remains, such as the Ice Man in Tyrol, the bones of some Native American humans. Pabo's research colleagues now had a complete grasp of ancient DNA laboratory technology. But according to the technology of that time, it was not possible to give a satisfactory answer as to whether the ancient DNA of sapien humans and the DNA of laboratory humans had mixed in the laboratory or not. So he began to focus on the original research to obtain the DNA of Neanderthal humans, which could be very different from the sapien humans, and in 1997 succeeded in obtaining and sequencing the mitochondrial DNA of Neanderthal humans. This was an important step in the research of ancient DNA. Noticing his research, the Max Planck Society in Germany invited Pabo to the post of founding president of the newly established Max Planck Institute of Evolutionary Anthropology. Pabo has played a major role in building the world's best multidisciplinary institute of humanities research. Pabo's research team released the complete genome of Neanderthal humans in 2010, further developing the technology for obtaining ancient DNA and using a new generation of DNA sequencing machines. In 2008, scientists excavated a fragment of an ancient human fingertip in a cave in Denisova, Russia. Which human does this piece belong to? Neanderthal or Sapien? It was not possible to prove this from just one piece of seed. Such studies require the human skull. But in 2011, Pabo and his colleagues extracted ancient DNA from this piece of seed and found it belonged to a third human species. For the first time in the history of anthropology, human species were determined not by skulls and bones, but by ancient DNA. Since then, laboratory methods and techniques have made it possible to extract ancient DNA not only from bones but also from the soil of caves inhabited by ancient humans. For decades of such revolutionary research, Svante Paabo is considered the father of the field of paleo-genomics and is honored with this Nobel Prize.
What exactly did anthropology add to knowledge?
The revolutionary emergence of the science of paleo-genomics has shed new light on human evolution and raised many new questions for research. After studying the Neanderthal human genome, it is now clear that the Neanderthal is not the ancestor of the sapien human, but the closest extinct relative. The evolutionary branches of sapien humans and Neanderthal humans diverged eight million years ago. When modern sapiens began to spread around the world from Africa around 70,000 years ago, they came into contact with Neanderthals from Asia and Europe and interbreeded. Today, between one and four percent of Neanderthal DNA is found in the genomes of European or Asian humans outside of Africa. Similar hybrids have occurred between Denisovan humans and Neanderthal humans, as well as between Sapien humans and Denisovan humans. One to six percent of Denisovan DNA is found in humans from Southeast Asia. That is, it is now proven that humans are not a 'pure', closeted species, but that we all carry bits of DNA from other human beings, at least in small amounts. Evidence of Neanderthal, Denisovan and Sapiens hybridization is not only of bookish or academic importance, but we see very important changes in Sapiens humans due to this hybridization. Many immune genes have passed from Neanderthals to sapiens. Human communities living in Tibet show some adaptations to living in high altitude regions. Genes from Denisovan humans to sapiens humans are responsible for this adaptation. The crisis of Corona is still not completely averted. Some pieces of DNA passed down from Neanderthals to us have been responsible for severe forms of Covid. But
Other similar fragments of Neanderthal DNA also confer complete protection against Covid in some individuals. Brain function depends on how and how many connections neurons in the brain can make with each other. Nerve cells have been studied in laboratory mice genetically modified with genes from Neanderthal humans and mice genetically modified with genes from sapien humans. Finding that Neanderthal neurons could not make the same connections as sapien humans, the research says a lot about the brain behind the relatively simple and unchanging culture of Neanderthal humans and the brain behind the complex culture of modern sapien humans.
Current research into the exact genes that make modern sapien humans so unique and how they work would not have been possible without Pabo's paleo-genomic knowledge. Pabo's research into human evolution and anthropology not only gave rise to the field of paleo-genomics, but also revolutionized knowledge in anthropology, archeology and medicine, and for this revolutionary research with far-reaching implications, Pabo was awarded the Nobel Prize.
