Genetic sequencing of human remains dating back 45,000 years has revealed a previously unknown migration to Europe and showed that mixing with Neanderthals during that period was more common than previously thought.
The research is based on analysis of several ancient human remains – including an entire tooth and bone fragments – found in a cave in Bulgaria last year.
Genetic sequencing found that the remains came from individuals more closely associated with today̵
“This indicates that they belonged to a modern human migration to Europe that was not previously known from the genetic record,” said the research, published Wednesday in the journal Nature.
It “also provides evidence that there was at least some continuity between the earliest modern humans in Europe and later humans in Eurasia,” the study added.
The results “shifted our previous understanding of early human migrations to Europe,” said Mateja Hajdinjak, an associate researcher at Germany’s Max Planck Institute for Evolutionary Anthropology, who helped lead the research.
“It showed how even the earliest history of modern Europeans in Europe may have been tumultuous and involved the change of population,” she told AFP.
One possibility raised with the results is “a proliferation of human groups, which are then replaced [by other groups] later in Western Eurasia, but continue to live and contribute descent to the people of Eastern Eurasia, ”she added.
The remains were discovered last year in the Bacho Kiro cave in Bulgaria and were hailed at the time as proof that humans lived with Neanderthals in Europe significantly earlier than once thought.
Genetic analysis of the remains also revealed that modern humans in Europe at that time mingled more with Neanderthals than had previously been assumed.
All of the Bacho Kiro cave individuals have Neanderthal ancestors five to seven generations before they lived, suggesting that the mixture [mixing] between these first people in Europe and the Neanderthals was common, ”said Hajdinjak.
Earlier evidence of early human-Neanderthal mixing in Europe came from a single individual called Oasis 1, which dates back 40,000 years and is found in Romania.
“Until now, we could not rule out that it was a random find,” Hajdinjak said.
The results were accompanied by separate research published Wednesday in the journal Nature Ecology and Evolution involving genome sequencing of samples from a skull found in the Czech Republic.
The skull was found in the Zlaty kun area in 1950, but its age has been the subject of debate and conflicting findings for decades.
The initial analysis suggested that it was older than 30,000 years old, but radiocarbon dating gave an age closer to 15,000 years.
Genetic analysis now appears to have solved the case, suggesting an age of at least 45,000 years old, said Kay Prufer of the Max Planck Institute’s Department of Archeogenetics, who led the research.
“We make use of the fact that anyone who traces their ancestors back to the people who left Africa more than 50,000 years ago carries some of the descent of the Neanderthals in their genomes,” he told AFP.
These Neanderthal traces appear in short blocks in modern human genomes and ever further back in human history.
“In older individuals, like the 45,000-year-old Ust’-Ishim man from Siberia, these blocks are much longer,” Prufer said.
“We find that the genus Zlaty kun’s genome has even longer blocks than the Ust’-Ishim man’s. This makes us sure that she lived at the same time or even earlier. ”
Despite dating from about the same period as Bacho Kiro remains, the Zlaty kun skull does not share genetic links to either modern Asian or European populations.
Prufer now hopes to examine how the populations that produced the two sets of remains were related.
“We do not know who the first Europeans were who ventured into an unknown country,” he said.
“By analyzing their genomes, we find out part of our own history that has been lost in time.”