The origin of humanity can be summed up as a long story of hybridization and migration. The more data we have about the prehistory of our species, mainly thanks to the genetic revolution led by Nobel laureate Svante Pääbo, the more complex and at the same time the simpler the picture: over the course of millennia, different species from Homo— to which we ourselves belong — populated the Earth in successive waves from Africa, some successful, others doomed to extinction. The study of fossil DNA has also shown that different species interbred along the way, and that these genetic exchanges helped bring to light the only humans who now inhabit Earth: Homo sapiensour.
Latest news on Neanderthals and Denisovans – the two archaic human species closest to us that went extinct about 40,000 years ago, although many sapiens they still carry their genes — they just confirmed this long journey, geographical as well as genetic.
It all started when Swedish scientist Svante Pääbo had the intuition that it was possible to extract and analyze the DNA of species that died thousands of years ago. As with many scientific advances, he initially had to work alone, secretly performing genetic analyzes on mummies. We mustn’t forget that no one believed – or funded – Hungarian researcher Katalin Karikó when she decided to study messenger RNA, a discovery that won her a Nobel Prize and, no less important, helped stop the Covid-19 pandemic.
By sequencing the Neanderthal genome, Pääb’s team at the Max Planck Institute for Evolutionary Anthropology found in 2010 that modern non-African humans share approximately 3% of their genes with this extinct human species. And by analyzing scattered and small bone remains found in a cave in Siberia, he discovered another human species, closely related to the Neanderthals, named after the cave where they were discovered: the Denisovans. It also allowed him to identify the first known hybrid hominin in history, Denisova 11, aka Daily, who died 50,000 years ago at the age of 13 and who had a Neanderthal mother and a Denisovan father. The fact that a hybrid hominin has appeared among the few remains of this species shows how constant the exchanges must have been.
For most researchers – some still deny Denisovans a distinct species category – Neanderthals lived in Europe and Denisovans lived in Asia. Both species disappeared with the arrival of Homo sapiens or, as seems increasingly clear, were absorbed by the new humans. To a certain extent, we are them too. Science recently published magazine the result of the analysis of three complete Neanderthal genomes: they did not become extinct, but rather assimilated. Eventually, successive waves of Homo sapiens immigration from Africa overwhelmed Neanderthals until they were unable to remain a separate species and were eventually assimilated by sapiens genetics, geneticist Joshua Akey, co-author of the study, summarized.
The last Neanderthals were a group of about 2,500 individuals lost in the vastness of prehistoric Europe. Their solitude also represents a human history that has become multiple—at one point, 200,000 years ago, as many as eight different human species coexisted on Earth. Now it’s just us, the people that French paleoanthropologist Jean-Jacques Hublin defines as “a solitary species.”
Information about the Denisovans, like their remains, is much more scarce, although an exciting map of the species’ evolution – and disappearance – is gradually being drawn. At the beginning of July, Science published the discovery of a Denisovan rib about 40,000 years old, the last found remains (at that time Homo sapiens colonized Australia from Africa and reached Europe). “This is extremely recent,” Bence Viola, a paleoanthropologist at the University of Toronto who was not involved in the research, said in the Science article. “The date puts the Denisovans well within the time frame of modern humans in the world.” [wider] region.”
Researchers Silvana Condemi and François Savatier have just published a book L’énigme denisova (Enigma Denisova, not yet translated from French), which collects all known data on these people whose genetic heritage is found in populations from as far away as Australia or the Bataan Peninsula in the Philippines. With their genes, they helped modern humans survive in high places like Tibet or face pathogens in rainforests like the Philippines.
This is how the authors describe, for example, what has happened in the Denisova cave, in the Altai massif, a place where cultures have crossed paths since the dawn of time: “The general panorama of human life in Denisova is now clear. : for tens of thousands of years, during the interglacial period, Neanderthals and Denisovans – two human species closer to each other than to Homo sapiens – visited the cave and met there. Some researchers even believe that the two species may have established a common culture in Altai.”
The vision of that cave in which different species lived together may be too idyllic: at many other sites, such as the Cueva del Castillo in Cantabria, northern Spain, there are signs of both Neanderthal and H. sapien occupation, but they are not simultaneous. . When one group arrived, the other group had already disappeared. But genetic exchanges are indisputable – even if they seemed impossible just two decades ago – and it is now certain that Neanderthal and Denisovan genes helped modern humans adapt and survive. But it is also evident that they are no longer there – even though we have inherited their DNA – and that H. sapiens is the only species that inhabits the Earth. Our arrival meant their extinction, but not without mixing first. The origin of humanity shown by the Paleogenetic Revolution has become a story of migration and admixture. And it certainly offers much reading for our intolerant present.
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