In December 2010, in the rocky depths of a cave in the Altai massif, a team of Russian researchers unearthed a tiny piece of phalanx bone. The recent discovery, hidden under tons of sediment for millennia, had the effect of a bomb in the scientific community. The sequencing of human DNA revealed a species that was previously unknown, “neither Neanderthal, nor sapiens, nor Martian…” explain paleoanthropologist Silvana Condemi and journalist François Savatier in their new book. The duo, who had already outlined the genealogical tree between Neanderthal and Homo sapiens (Neanderthal, my brother), this time leads the investigation into this revolutionary story, the captivating background of which they recount in great detail.
This extinct species—yet part of the puzzle of humanity—is called Denisova, after the cave in Siberia. It was first identified not by its fossils, but by its DNA. But who were the Denisovans, these “other” humans who once populated Asia from north to south? As science has shown us many times, there is no clear and definitive answer to this question. It took a long time for researchers to discover and admit that our ancestors Homo sapiens interbred with Neanderthals. However, about 2% of our genes come from our distant cousins who are now extinct. Thanks to genetics, our knowledge of the subject has taken a giant step forward. However, the information we currently have on the Denisovans, as well as on their remains, is much more scattered, even if little by little a fascinating map of the evolution – and disappearance – of this species is emerging as discoveries are made.
The authors of the book also point out that SapiensNeanderthals and Denisovans all descend from a common ancestor known as theHomo heidelbergensis. The chapters, written as in a detective story with a paleogenetic twist, follow the ancestral timeline. 750,000 years ago, Sapiensa species of hominids from Africa, to which we belong, spread across Eurasia in successive waves. Two archaic groups continued the journey further, the Neanderthals in the west and the Denisovans in the east. Scientists believe that the break in their human lineage occurred 400,000 years ago, a trifle on the evolutionary scale.
But what is fascinating is that this eastern brother would have populated an immense geographical territory extending from Altai to the Philippines, which would explain why in New Guinea, the population still carries up to 5% of Denisovan DNA. Silvana Condemi and François Savatier share the theory commonly accepted in paleontology that the origin of humanity can be summed up in a long history of hybridization and migrations. Even if Neanderthals and Denisova no longer exist, they were probably absorbed by Homo sapiensbut the genetic heritage certainly still lives within us.