Ancient DNA Reveals Contrasting Fates of Hunter-Gatherer Groups in Europe

Ancient DNA gathered from the bones and teeth of hunter-gatherers who lived as the Last Glacial Maximum was waning, around 19,000-25,000 years ago, has revealed exciting new information about our ancestors. The largest gathering of the genetic prehistoric record of Europe has been analyzed in a pair of new studies, from the remains of 357 ancient Europeans. These have revealed that several waves of hunter-gatherers migrated into Europe, from at least 8 different populations that were genetically very far away from each other.

So Close and Yet So Far!

The two studies published in Nature analyzed the co-existence of these different populaces, who lived alongside each other for thousands of years. They traded tools and shared certain cultural attributes, like tools, weapons and art, though would succumb eventually either to warring or the harsh brutality of the Ice Age, with only some groups surviving.

The studies collectively suggest that Western European hunter-gatherers were able to outlast the icy blast, while Easterners were replaced by migrations of newcomers, according to a University of Tubingen press release.

“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, a lead author of one study, and a co-author of the other, whose authorship has been led by palaeogeneticist Cosimo Posth.

The study found that during this period, ice sheets expanded across much of northern Europe, making a vast expanse of land uninhabitable. As previously thought, southwestern Europe provided a refuge from the cold for hunter-gatherers in and around that region. However, contrary to previous assumptions, southeastern Europe, where Italy is now located, did not offer lasting respite from the cold for nearby groups, reports Science News.

While the first study analyzed the 357 remains of every ancient hunter-gatherer on record, the second study used the oldest hunter-gatherer genome recovered from the southern tip of Spain, belonging to someone who lived approximately 23,000 years ago.

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Oldest evidence of migration during a climate warming: Male and female skull buried in western Germany (Oberkassel) about 14,000 years ago. Genetically those individuals derived from the south. (Jürgen Vogel, LVR-LandesMuseum Bonn/Nature)

Survival of the Fittest?

Modern humans first began to spread across Eurasia approximately 45,000 years ago, arriving from the near east, but scientists are only beginning to understand why so many groups emerged at this time in history. It appears that when farmers first arrived in Europe around 8,000 years ago, they came into contact with the descendants of a long history. These descendants included light-skinned individuals with dark eyes in the east, and possibly dark-skinned individuals with blue eyes in the west.

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

When these human groups migrated to Europe, they encountered the Neanderthals, who had already been living across the continent for more than 100,000 years. However, the Neanderthals disappeared about 40,000 years ago, and the reasons for their extinction remain a topic of debate. Some scientists suggest that modern humans outcompeted them with superior tools and technology, while others propose that climate change, disease, or other factors may have played a role.

Around 33,000 years ago, Europe began experiencing a much colder climate, giving rise to a new culture known as the Gravettian. This culture was characterized by hunters who made spears to hunt large game such as woolly mammoths, as well as the creation of Venus figurines that may have represented fertility.

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The prehistoric human groups that archaeologists refer to as Gravettian were widespread in Europe about 32,000-24,000 years ago. Despite sharing several similar cultural traits, Gravettian populations from western and eastern/southern Europe were genetically different. The west Gravettian population (left) survived during the Last Glacial Maximum while the eastern and south Gravettian populations disappeared. (Michelle O‘Reilly and Laurent Klaric, inspired by the original work by Benoit Clarys/Nature)

Distinct Genetic Groups and Response to Changing Climates

A team of researchers led by Dr. Johannes Krause and Dr. Cosimo Posth found DNA samples from Gravettian remains scattered throughout Europe. The team initially expected to find all individuals to belong to a single genetic population, but instead discovered two distinct groups - one in France and Spain and the other in Italy, the Czech Republic, and Germany.

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

These two distinct groups, Fournol (the DNA of the 23,000-year-old skeleton of the man from Spain was also Fournol) and Vestonice respectively, belonged to two separate waves of migration into Europe. Upon arrival, they shared the Gravettian culture for thousands of years, though remained genetically distinct. Clearly, these two groups were not isolated from each other, as the new studies have shown.

Additionally, the retreat of the glaciers caused the Vestonice to not survive the Ice Age, but some descendants of the Fournol continued living in the Iberian Peninsula. An offshoot of the Fournol moved northwards and was now known as GoyetQ2. Another population of hunter-gatherers from the Balkans, called the Villabruna, moved into Italy and replaced the Vestonice.

The Villabruna crossed over the Alps around 14,000 years ago and here encountered the GoyetQ2 people. A new population emerged in Europe. This population's ancestry was three parts Villabruna and one part GoyetQ2. They named this group the Oberkassel. The Oberkassel people spread across Europe, replacing the GoyetQ2 population, according to a New York Times report.

Perhaps with the melting of the ice and the emergence of forests, the Oberkassel people were more suited to hunting and survival in this terrain, compared to the GoyetQ2. The key takeaways from these landmark studies are that the population of Europe was constantly changing and that new groups were arriving and replacing old ones. This ties up with modern patterns of migration, particularly in contemporary Europe, and its effect on the genetic makeup of states formed around ‘ethnicity’. 

Top image: Reconstruction of a hunter-gatherer associated with the Gravettian culture (32,000-24,000 years ago), inspired by the archaeological findings at the Arene Candide site (Italy). Source: Tom Bjoerklund/Nature

By Sahir Pandey