About 45,000 years ago, a tiny group of people (less than 1,000 individuals) wandered through the frozen northern reaches of Europe. Across thousands and thousands of kilometers of tundra, they hunted woolly rhinos and other large, big-game animals.
Most likely his skin was dark. To keep warm in the freezing temperaturesthey probably wore the skins of the animals they killed to cover themselves.
These resilient Ice Age people, known as the LRJ culture (acronym for the cultural period Lincombiano-Ranisiano-Jerzmanowskiano), they left behind stone tools characteristics and its own remains in caves scattered throughout Europe. Some very valuable prints
A few weeks ago something more was learned about them. Researchers revealed the genomes of seven individuals of the LRJ culture from fossilized bones found in Germany and also in the Czech Republic.
That important material turned out to be something very vital: nothing less than the oldest genetic samples of modern humans found so far.
It turns out that the LRJ were part of the first human expansion from Africa to other parts of the world.
But theirs was a surprisingly recent migration.
The great journey of humanity
The common ancestors of the representatives of this culture, the LRJ, and the current non-Africans lived about 47,000 years ago.
On the other hand, studies of remains found in Australia suggest that Modern humans arrived on that continent about 65,000 years ago.. And in China, researchers found what look like bones of modern humans from 100,000 years ago.
The huge difference between those ages, those statistics marking different times, could change our understanding of how humans spread across the world.
If the ancestors of today’s non-Africans did not cross other continents until 47,000 years ago, then those oldest places must have been occupied by previous waves of humans who died without passing on their DNA to people now living in places like China and Australia.
“They cannot be part of the genetic diversity present outside of Africa,” says Johannes Krause, a geneticist working at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and author of the new study. The newly discovered genomes, then, come from fossils that baffled scientists for decades.
In 1950, archaeologists excavating a cave in what is now the Czech Republic found the skull of an ancient woman. However, they could not determine his age.
They also found stone tools at the site, known as Golden horse (an expression in Czech that means “golden horse”), but they were not distinctive enough to associate the woman with any specific cultural group.
A few years ago, researchers at Max Planck They managed to extract some DNA from the skull. A preliminary analysis suggested that the woman belonged to an ancient branch of humans.
Meanwhile, another set of ancient bones arrived from a cave in Germany called Frogsand unos 140 kilometers al oeste de Zlatý koň.
The remains of Frogs They were discovered more than a century ago. Archaeologists had come to the conclusion that they all belonged to the same ancient culture, which they called the cultural period. Lincombiano-Ranisiano-Jerzmanowskianoor LRJ for short. But they didn’t know much more than that. It was not clear, for example, whether the inhabitants of LRJ Were they modern humans or were they actually Neanderthals?.
Fossils and genomes
In 2016, a team of archaeologists returned to Ranis to reassess the site. Marcel Weiss, an archaeologist at the University of Erlangen-Nuremberg, Germany, and his colleagues discovered a new batch of fossils and tools and they used 21st century methods to analyze them in depth.
The fossils analyzed contained a large amount of DNA, enough to reconstruct the genome of six individuals.
They were all closely related to each otherincluding a mother and her daughter. The scientists also discovered that two of them were closely related to Zlatý kůň’s wife.
“It’s the same group, the same extended family. It could be that they knew each other,” Krause said.
The researchers calculated that the seven sets of fossils They were at least 45,000 years old. Their genomes now bring the LRJ people out of the shadow of history.
Their genetic similarity indicates that they belonged to a tiny population that numbered only a few hundred people at any given time.
And the close kinship between the six Frogs and the Golden horse suggests that the LRJ roamed in small bands, wrapped in the skins of animals they hunted, over long distances and spent little time in the same place.
“If I went to New York and took one person from the Bronx and then went to Long Island and took another person from there, it would be unlikely that these two would have a common ancestor in the last three generations”says Kay Prüfer, a paleogeneticist at Max Planck and co-author of the new study. “But, of course, we are talking about the deep past, when things were clearly different.”
A genetic truth
Paleogeneticist Prüfer and her colleagues discovered that the inhabitants of LRJ lacked some key mutations that are present in living Europeans.
For example, they lacked the genes that produce pale skin, suggesting they had dark pigmentation, like their ancestors from Africa.
Family tree
The scientists also used the deciphered genomes to find out where LRJs fit in the human family tree. Previous studies had established that Human ancestors evolved over millions of years in Africa.
About 600,000 years ago, the ancestors of the Neanderthals branched off on their own. They spread throughout the Near East and settled in Europe and Western Asia. Neanderthals, it is known according to scientific analysis, lasted for hundreds of thousands of years and disappeared from the fossil record about 40,000 years ago.
Modern humans, furthermore, They stayed longer in Africa before expanding to other continents. When they encountered Neanderthals, possibly in the Middle East region, they interbred.
It is also known that, today, all humans in the world carry at least a trace of Neanderthal DNA.
Although the general lines of this story are well defined, Scientists are still struggling to pin down the details.. Estimates for when modern humans and Neanderthals first interbred range between 54,000 and 41,000 years ago, for example.
Krause and his colleagues found that, unlike living humans, LRJs had long stretches of Neanderthal DNA in their genomes.
This suggests that relatively little time had passed since modern humans interbred with Neanderthals. Krause and his colleagues They calculate that interbreeding took place between 1,000 and 2,500 years before, that is, about 46,000 years ago.
In another study published a few weeks ago, a second team of scientists reached a similar conclusion by analyzing Neanderthal DNA in fossils and also in living people.
“It was really cool to see a similar date,” said Priya Moorjani, a paleogeneticist at the University of California, Berkeley and author of the second study.
Independent scientists said the new chronology suggested modern humans moved from the Near East to the northern margins of Europe. at a remarkable speed. “The time frame is getting really tight,” said Pontus Skoglund, a paleogeneticist at the Francis Crick Institute in London.
Skoglund also said it would be strange if non-African ancestors had emerged about 47,000 years ago, while modern humans from Asia and Australia dated back 100,000 years.
According to him, the sites in question could be incorrectly dated, or humans could have reached Asia and Australia that long agoonly to become extinct.
He Yu, a paleogeneticist at Peking University who was not involved in either study, said the mystery won’t be solved until scientists find DNA in some of the ancient Asian fossils.
“We still need early modern human genomes from Asia to really talk about the stories of Asia,” Yu said.
Translation: Patricia Sar