Ancient DNA Reveals History of Hunter-Gatherers in Europe

In the 1800s, archaeologists began to piece together Europe’s deep history from the bones of ancient hunter-gatherers and the iconic art they left behind, such as cave paintings, fertility figurines, and statues of “man-lion”.

Over the past decade, geneticists have added a new dimension to that story by extracting DNA from teeth and bones.

And now, in a pair of studies published Wednesday‌, the researchers have produced the most robust analysis yet of the genetic record from prehistoric Europe.

By looking at DNA extracted from the remains of 357 ancient Europeans, the researchers found that several waves of hunter-gatherers immigrated to Europe. The studies identified at least eight populations, some more genetically different from each other than today’s Europeans and Asians. They coexisted in Europe for thousands of years, apparently trading tools and sharing cultures. Some groups survived the Ice Age, while others disappeared, perhaps wiped out by other groups.

“We are finally understanding the dynamics of European hunter-gatherers,” said Vanessa Villalba-Mouco, a paleogeneticist at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and author of both studies.

The new genetic analysis suggests that when farmers arrived in Europe around 8,000 years ago, they encountered the descendants of this long history, with light-skinned, dark-eyed people to the east, and possibly dark-skinned, blue-eyed people to the east. West.

Dr. Villalba-Mouco and her colleagues have given these peoples a list of new names that can be as difficult to memorize as the kingdoms of West: Fournol, Vestonice, GoyetQ2, Villabruna, Obserkassel and Sidelkino, among others.

But scientists are just beginning to understand how so many different groups arose between 45,000 and 5,000 years ago.

“I didn’t expect this amount of replacements and ancestry changes,” said Carles Lalueza-Fox, director of the Barcelona Natural Sciences Museum and author of one of the new papers. “We still lack an understanding of why these movements were triggered. What happened here, why it happened, is strange.”

Modern humans arose in Africa and spread to other continents around 60,000 years ago. Last year, archaeologists reported what may be the oldest evidence of those humans reaching Europe: a set of 54,000 year old teeth in a french cave

When these groups arrived in Europe, Neanderthals had already lived throughout the continent for more than 100,000 years. Neanderthals disappeared around 40,000 years ago, perhaps because modern humans outmaneuvered them with superior tools.

But the oldest DNA from modern humans in Europe, dating back 45,000 years, undermines such a simple story. It comes from people who belonged to a lost branch of the human family tree. Their ancestors were part of the expansion out of Africa, but split up on their own before the ancestors of living Europeans and Asians split up.

These early Europeans have almost no genetic link to younger remnants of hunter-gatherers. It appears that the first modern humans in Europe may have disappeared along with the Neanderthals, said Cosimo Posth, a paleogeneticist at the University of Tübingen in Germany and an author of the two papers published Wednesday.

“It’s actually quite interesting that early modern humans also had a very difficult time surviving,” said Dr. Posth.

Before the advent of ancient DNA analysis, archaeologists named cultures based on the styles of things they made. The oldest modern human culture in Europe is known as the Aurignacians, named for the oldest figurative cave paintings and sculptures on the continent.

Around 33,000 years ago, as the climate cooled, a new culture called the Gravettian emerged across Europe. Gravettian hunters made spears to kill woolly mammoths and other large game. They also made so-called Venus figurines that could have represented fertility.

Dr. Posth and his colleagues found DNA in Gravettian remains scattered throughout Europe. The scientists expected that all the individuals came from the same genetic population, but instead they found two distinct groups: one in France and Spain, and another in Italy, the Czech Republic and Germany.

“They were very different, and this was a big surprise to us because they practiced the same archaeological culture,” Dr. Posth said.

Dr. Posth and his colleagues named the western population the Fournol people, and found a genetic link between this group and 35,000-year-old Aurignacian remains in Belgium.

They named the eastern group Vestonice and found that they share ancestry with 34,000-year-old hunter-gatherers who lived in Russia.

That genetic chasm led Dr. Posth and his colleagues to argue that Fournol and Vestonice belonged to two waves that migrated to Europe separately. After their arrival, they lived for several thousand years sharing Gravettian culture but remaining genetically distinct.

“This result is, in my opinion, groundbreaking,” said Anaïs Luiza Vignoles, an archaeologist at the University of Paris who was not involved in the study.

Dr. Vingoles said archaeologists could now investigate the type of cultural contacts these two populations had. It’s clear from the new study that they weren’t completely isolated from each other. In Belgium, scientists found 30,000-year-old remains with a mix of Fournol and Vestonice ancestry.

Jüergen Richter, an archaeologist at the University of Cologne who was not involved in the new studies, suggested that in these sporadic contacts between the two peoples, they might have shared cultural ideas and artifacts such as the figure of fertility. “I’m not absolutely surprised,” he said of the new findings.

Around 26,000 years ago, the two groups faced a new threat to their survival: an advancing wall of glaciers. During the Ice Age, between 26,000 and 19,000 years ago, European hunter-gatherers were shut out from much of the continent, surviving only in southern havens.

Dr. Villalba-Mouco and colleagues shed light on the haven of the Iberian Peninsula, the region now occupied by Spain and Portugal, by studying DNA in the teeth of a 23,000-year-old man found in a cave in southern Spain . His DNA revealed that he belonged to the Fournol people who lived in Iberia before the Ice Age. The researchers also found genetic markers linking it to a 45,000-year-old skeleton discovered in Bulgaria.

When the glaciers receded, some Fournol descendants continued to live in Iberia. But others spread north as a new population, which Dr. Posth and his colleagues named GoyetQ2. “It really looks like a peopling of Europa after the last glacial maximum,” he said.

Vestonice, by contrast, did not survive the Ice Age. When the glaciers were at their fullest, Vestonice may have lingered for a while in Italy. But Dr. Posth and his colleagues found no Vestonice ancestry in Europeans after the Ice Age. Instead, they discovered a population of hunter-gatherers that appeared to have spread from the Balkans, known as Villabruna. They moved to Italy and replaced Vestonice.

For several thousand years, the Villabruna were limited to southern Europe. Then, 14,000 years ago, they crossed the Alps and met the GoyetQ2 people to the north. A new population arose, its ancestry three parts Villabruna to one part GoyetQ2.

These new people, which Dr. Posth and his colleagues named Oberkassel, spread across much of Europe, replacing the old GoyetQ2 population.

Dr. Posth speculated that another climate change could explain this new wave. About 14,000 years ago, a strong warming pulse produced forests across much of Europe. The Oberkassel people may have been better at hunting in the forests, while the GoyetQ2 retreated with the shrinking steppes.

To the east, the Oberkassel encountered a new group of hunter-gatherers, probably arriving from Russia. Scientists named the descendants of this group, who lived in Ukraine and the surrounding regions, Sidelkino.

But in Iberia there were no large sweeps of newcomers replacing the older ones. The Iberians after the Ice Age still had a large ancestry from the Fournol people who had arrived there thousands of years before the glaciers advanced. The Villabruna people moved to northern Spain, but added their DNA to the mix rather than replace those who were there before.

When the first farmers arrived in Europe from Turkey around 8,000 years ago, three large groups of hunter-gatherers thrived across Europe: the Iberians, the Oberkassel, and the Sidelkino. Living Europeans carry some of their genes, which allowed Dr. Posth and his colleagues to make some guesses about the physical appearance of ancient populations.

The Sidelkino people in the east had genes associated with dark eyes and light skin. The Oberkassel in the west, by contrast, probably had blue eyes and may have had dark skin, although it is more difficult to be sure of their appearance than the Sidelkino.

These three groups of hunter-gatherers remained isolated from each other for about 6,000 years, until farmers from Turkey arrived. After this advent of agriculture, the three groups began to mix, the scientists found. It is possible that the expansion of farmland forced them to move to the margins of Europe to survive. But over time, they were absorbed into the surrounding farming communities.

Ludovic Orlando, a molecular archaeologist at Paul Sabatier University in France who was not involved in the new research, said it was a milestone in the study of early humans. “I was really impressed,” he said.

Dr. Orlando said that each continent will probably have its own history of hunter-gatherer migrations. The researchers were able to probe the history of Europe in such detail because they were able to tap into 150-year-old remains that have been stored in museums there.

But he predicted that scientists won’t have to dig up many new skeletons on other continents to piece together their genetic histories. This is because it is now possible to extract human DNA from cave sediments instead of searching for bones and teeth.

“We cannot develop a Eurocentric view of the past,” said Dr. Orlando.