More Mysterious Than Neanderthals, Denisovans Hold Key to Humanity | Science

The origins of humanity can be described as a long history of hybridizations and migrations. The more data we have about the prehistory of our species, especially thanks to the genetic revolution led by Nobel laureate Svante Pääbo, the more complex and simpler the picture becomes: over the course of millennia, different species homo — to whom the sample belongs — populated the Earth in successive waves from Africa…

The origins of humanity can be described as a long history of hybridizations and migrations. The more data we have about the prehistory of our species, especially thanks to the genetic revolution led by Nobel laureate Svante Pääbo, the more complex and simpler the picture becomes: over the course of millennia, different species homo — to whom the sample belongs — populated the Earth in successive waves from Africa, some successful, others doomed to extinction. Research into fossil DNA has also shown that the paths of different species crossed on this journey, and that this genetic exchange helped lead to the only human species inhabiting the Earth today: Homo sapiensus.

News about Neanderthals and Denisovans, the two closest to our species of humans, who died out about 40,000 years ago, although many of them are still sapiens they carry their genes, which, as has become known in recent days, only confirm this long journey, geographical, but also genetic.

It all started when Swedish scientist Svante Pääbo intuitively realized that it was possible to extract and analyze the DNA of species that had been extinct for thousands of years. As with many scientific advances, he initially had to work alone, secretly conducting genetic analyses of mummies. We should not forget that no one believed or funded Hungarian Katalin Karikó when she decided to study messenger RNA, a discovery that led to her Nobel Prize and, just as importantly, to stopping the Covid-19 pandemic.

By sequencing the Neanderthal genome, Pääbo’s team at the Max Planck Institute for Evolutionary Anthropology found in 2010 that modern non-African humans share about 3% of their genes with this extinct human species. And by analyzing scattered, small bone remains found in a cave in Siberia, he discovered another species of humans closely related to Neanderthals, named after the cave where they were discovered: the Denisovans. This also allowed him to identify the first-ever mestizo, Denisova 11, a pseudonym Dannya woman who died at age 13 50,000 years ago, to a Neanderthal mother and a Denisovan father. The fact that a mestizo appeared among the few remains of this species found shows how constant the exchanges must have been.

According to most researchers (some still deny that Denisovans are a separate species), Neanderthals lived in Europe and Denisovans lived in Asia. Both species disappeared with the arrival of sapiens or, as is increasingly clear, they have been absorbed by new people. In a way, we are them. Last week, Nuño Domínguez spoke in EL PAÍS about the magazine’s latest achievements. The science, the fruit of an analysis of three complete Neanderthal genomes: they did not go extinct, but rather were assimilated. “Eventually, successive waves of sapiens immigration from Africa overwhelmed the Neanderthals until they could no longer remain a distinct species and were finally assimilated by genetics.” sapiens— summed up geneticist Joshua Akey, co-author of the study.

The last Neanderthals numbered about 2,500 individuals, lost in the vastness of prehistoric Europe. Their loneliness also represents the history of humanity, which has become plural – at one point, 200,000 years ago, up to eight different human species coexisted on Earth. Now there are only us, humans, whom the French paleoanthropologist Jean-Jacques Hublin describes as “the solitary species.”

As for the Denisovans, information, like their own remains, is much less available, although a fascinating map of the evolution – and extinction – of the species is slowly emerging. Journal The science in early July, published a report on the discovery of a Denisovan rib dating back about 40,000 years, the most recent remains found so far (at the time Homo sapiens They colonized Australia from Africa and reached Europe. “This happened quite recently,” he said in the article. The science Bence Viola, a paleoanthropologist at the University of Toronto who was not involved in the study, said: “This date puts the Denisovans within the time frame of modern humans in the region.”

Scientists Silvana Condémie and François Savatier have just published a book in French. L’énigme denisova (The Denisova Enigma, by Albin Michel, currently untranslated), which collects all the data known about these people, whose genetic heritage is found in populations as far away as Australia or the Bataan Peninsula in the Philippines. With their genes, they helped modern humans survive in high places, such as Tibet, or resist pathogens in tropical forests, such as the Philippines.

Here is how they describe, for example, what happened over the millennia in Denisova Cave, in the Altai Massif, a place where cultures have intersected since time immemorial: “The general panorama of human life in Denisova is now clear: for tens of thousands of years, during the interglacial periods, Neanderthals and Denisovans were two human forms closer to each other than to Homo sapiens— often visited the cave and met there. “Some researchers even believe that these two species could have founded a common culture in Altai.”

The vision of this cave where different species lived together may be too idyllic: many other places, such as Cueva del Castillo in Cantabria, are home to Neanderthals and sapiensbut they are not simultaneous. When one arrives, the other is already gone. However, the genetic exchange is undeniable – and seemed impossible just two decades ago – and there is certainty that Neanderthal and Denisovan genes have helped modern humanity adapt and survive. But it is also clear that they are no longer there – although we inherited their DNA – and that sapiens We are the only species inhabiting the Earth. Our arrival meant their disappearance, but not without prior mixing. The origins of humanity, as revealed by the paleogenetic revolution, were a history of migrations and mixing. And this, no doubt, opens up many possibilities for our intolerant present.

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