08/04/2021 at 2:51 AM #33477Anonymous UserParticipant
The disappeared original Europeans
Missing pioneers: The first representatives of Homo sapiens came to Europe 45,000 years ago – but could not establish themselves, as now suggested by genome analyzes of the oldest human fossils in Europe. Accordingly, these first pioneer populations apparently did not last – their genetic material has left no traces in today’s Europeans, as researchers now report in two publications in “Nature” and “Nature Ecology & Evolution”.
The long era of the Neanderthals ended around 45,000 years ago and the first representatives of Homo sapiens immigrated to Europe. But whether these first immigrants were able to persist and spread on our continent and how they were related to later hunters and gatherers in Europe is still largely in the dark. One of the reasons: There are only a handful of human fossils from this period. These include the 40,000-year-old fossil “Oase 1” from Romania, 45,000-year-old relics in the Siberian Ust’-Ishim, as well as the fossils of several individuals from around the same time recently discovered in the Bacho-Kiro cave in Bulgaria.
In addition: DNA analyzes of such finds are time-consuming and not always possible. “So far, only three genomes have been isolated from individuals who lived close to the time when Europe and Asia were first colonized more than 40,000 years ago,” explain Mateja Hajdinjak from the Max Planck Institute for Evolutionary Anthropology in Leipzig and her colleagues.
A look into the genome of the first Europeans
DNA analyzes of other early representatives of Homo sapiens are now providing new insights into the beginnings of European human history. The finds are the remains of three individuals from the Bacho Kiro cave in Bulgaria and the skull of a woman from Zlaty kun in the Czech Republic. Two research teams – one headed by Hajdinjak and one headed by Kay Prüfer from the Max Planck Institute for the History of Man in Jena – have now genetically examined these fossils and partially re-dated them.
In order to classify these early humans, the scientists compared their genome with that of modern Europeans and Asians, but also with the genome of the three human fossils from Europe that have already been sequenced. They also paid special attention to the proportion and length of Neanderthal gene sequences, as this reveals when and how intensively the ancestors of these early Homo sapiens representatives crossed with Neanderthals.
Bacho Kiro: descendants only in East Asia
The first result: the human fossils from the Bacho Kiro cave are among the oldest in Europe, but they were apparently not the direct ancestors of today’s Europeans. “The three individuals share more alleles with today’s populations from East Asia, Central Asia and the natives of the American continent than with populations from western Eurasia,” report Hajdinjak and her team.
The researchers conclude that these early immigrants moved to both Europe and Asia at the time. Unlike in East Asia, however, this population was not able to establish itself permanently in our country. Their descendants were ousted by representatives of Homo sapiens who later immigrated and their genetic material disappeared from the European gene pool.
Also interesting: the people from the Bacho-Kiro Cave had between 3.0 and 3.8 percent Neanderthal DNA in their genetic make-up – more than most Europeans today. “This suggests that the intermingling of Neanderthals and the first modern humans to arrive in Europe occurred more frequently than is often assumed,” the scientists said. From the length of the Neanderthal gene segments, they conclude that the last crosses between Neanderthals and the ancestors of these people were only six to seven generations ago.
Zlaty kun: The oldest European?
The genetic analysis of the skull from the Czech Republic also revealed something new: The Homo sapiens woman from Zlaty kun could therefore be much older than expected. So far, radiocarbon dating had yielded contradicting results – the span ranged from 15,000 to 27,000 years. But as it turned out, this was due to a subsequent contamination of the find: “We have found evidence of contamination with bovine DNA, which suggests that the skull parts were joined together with an animal-based adhesive in the past,” explains co-author Cosimo Posth from the University of Tübingen.
But how old is the homo sapiens woman from Zlaty kun? The Neanderthal DNA in their genome provided evidence of this. Because she also had remarkably long, uninterrupted Neanderthal segments in her genome. “Zlaty kun carries segments that are on average longer than those of all other Eurasian hunters and gatherers examined so far,” report Prüfer and his team.
You also conclude that this woman must have come from the beginning of the colonization of Eurasia by Homo sapiens. “Zlaty kun could thus be the oldest European human fossil with a preserved skull,” said the researchers.
But the population of this early European woman could not hold up in her new homeland: there are no traces of these early Homo sapiens representatives either in the genome of modern Europeans or in modern Asians. “As with Ust’-Ishim and Oase 1, Zlaty kun also shows no genetic continuity with modern humans from less than 40,000 years ago,” write Prüfer and his colleagues.
According to the research team, this suggests that this early population was also unable to establish itself in Europe. “It’s pretty exciting that the earliest modern humans in Europe were ultimately unsuccessful,” says senior author Johannes Krause from the MPI for the History of Man.
Was it a super volcano to blame?
A possible explanation for the failure of the first immigrants could have been an eruption of the super volcano under the Phlegraean Fields in Italy around 40,000 years ago, as the research team explains. Studies show that the ash rain from this eruption reached as far as Russia and that the released aerosols significantly cooled the climate of Europe for several years – it was in volcanic winters.
“This eruption strongly influenced the climate of the northern hemisphere and could have reduced the chances of survival of Neanderthals and early modern humans in large parts of western Eurasia,” speculate Prüfer and his team. This outbreak could have brought final extinction to the already heavily decimated Neanderthals. And the first European representatives of Homo sapiens could have fled the cold or died as well. (Nature, 2021; doi: 10.1038 / s41586-021-03335-3; Nature Ecology / & Evolution, 2021; doi: 10.1038 / s41559-021-01443-x)
Source: Nature, Max Planck Institute for Evolutionary Anthropology, Max Planck Institute for the History of Man
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