The puzzle is pieced together little by little. The mixing of a wise man with the Neanderthals, which would have occurred on the route of their migration from Africa to Eurasia, is more recent than we thought. This is what two studies published in the journals show Nature et ScienceThursday 12 and Friday 13 December.
An international team led by researchers from the Max Planck Institute for Evolutionary Anthropology in Leipzig (Germany) has sequenced the oldest known modern human genomes, belonging to seven individuals who lived between 42,000 and 49,000 years BCE. One of them (a complete female skull) comes from the archaeological site of Zlatý Kun (Czech Republic). The other six lived about 230 kilometers away, in the Ilsenhöle cave in Ranis (Germany). Analysis of their genome provides information on these pioneers who populated a vast territory stretching from the United Kingdom to Poland when they were only a few hundred individuals.
First surprise, “the individuals of Ranis and Zlatý Kun constitute the first known members of a modern human family, from a genetic point of view”explained Arev Sümer, first author of the study, during a press briefing. In Ranis, researchers identified three men and three women, including a mother and her daughter. Another individual was related to the mother in the second or third degree. Even more surprising, the skull found at Zlatý Kun is also a fifth or sixth degree relative, perhaps “a distant cousin or great-great-grandmother”.
Genetic variants have also provided clues about their appearance, suggesting “dark skin pigmentation and eyes, as well as brown hair, as would be expected for populations who had just left Africa”noted Arev Sümer. Above all, the hunter-gatherers of Ranis-Zlatý Kun carry in their genes the trace of a single mixture with the Neanderthals, who populated Europe and western Asia for hundreds of thousands of years when man modern has migrated there. This allowed the team to estimate the date of this original crossbreeding, a key element of our history.
Indeed, even today, all non-African populations carry in their genes 2 to 3% of Neanderthal DNA, a distant heritage of this mixture which “probably” produced on the migratory routes of the Middle East, according to Johannes Krause, one of the authors of the study. “We calculated that this event took place between 45 000 et 49 000 ans”approximately 80 generations before that of the Ranis-Zlatý Kun individuals, “which is much more recent than previously assumed”he reports. Early modern humans interacted with Neanderthals for about 7,000 years, summarized Mathilde Fontez, editor-in-chief at the magazine Epsilonon franceinfo. Neanderthals became extinct about 40,000 years ago whena wise manhe continued to populate the world.
Their result is corroborated by another study published simultaneously in the journal Science. This second team used a different method by comparing 300 contemporary and ancient genomes (including 59 taken from individuals who lived between 2,000 and 45,000 years BC) in search of traces of interbreeding with Neanderthals.
“The vast majority of Neanderthal gene flow occurred over a single extended period”notes Priya Moorjani, from the University of Berkeley (United States). “We dated this period between 43 500 years and 50 500 years, which is very consistent with the article’s estimate of Natureas well as with archaeological evidence, which has dated the overlap between Neanderthals and modern humans in Europe.”
This dating has important repercussions on the understanding of human evolution. It implies in particular that the migration of our lineage from Africa took place, at the latest, 43,500 years ago. It also means that the hundreds of anthropological or archaeological discoveries outside Africa attributed to modern humans over 50,000 years old – i.e. before the encounter with Neanderthals – cannot come from our direct ancestors. For Johannes Krause, “human history is not just a story of success. We have actually gone extinct several times”.
