Around 25,000 to 19,000 years ago, ice sheets extended over much of northern Europe, rendering vast areas of land uninhabitable. This harsh event began a previously unknown story of two human populations operating at opposite ends of the continent.
Western European hunter-gatherers survived an ice blast in the past. Migrations of newcomers replaced the Orientals.
These are the results of the largest study to date of the DNA of ancient Europeans, covering the period before, during and after what is known as the Last Glacial Maximum, paleogeneticist Cosimo Post and colleagues report March 1 in Nature .
As researchers have long believed, southwestern Europe became a refuge from the great cold of the last ice age for the hunter-gatherers who lived in and around the region, scientists say. But it turns out that southeastern Europe, where Italy is now located, didn’t offer the long-term respite from the cold for neighboring groups as previously thought.
Instead, these people were replaced by genetically distinct hunter-gatherers who probably lived eastward along the Balkan Peninsula. These people, who came from parts of southwest Asia, began traveling to what is now northern Italy about 17,000 years ago, when the ice age began to wane.
“If the local population [льодовикового періоду] in Italy did not survive and were replaced by groups from the Balkans, this completely changes our interpretation of the archaeological record,” says Post of the University of Tübingen in Germany.
Post and his colleagues’ findings are based on DNA analysis of 356 ancient hunter-gatherers, including new molecular evidence from 116 individuals from 14 countries in Europe and Asia. Excavated human remains that have yielded DNA have been dated to about 45,000 to 5,000 years ago.
Comparing the sets of gene variants inherited by these hunter-gatherers from a common ancestor allowed the researchers to reconstruct the population movements and substitutions that shaped the genetic makeup of ancient Europeans. For the first time, evidence of ancient DNA included people from the so-called Gravettian culture, which dates from about 33,000 to 26,000 years ago in central and southern Europe, and from southwestern Europe, the Solutrean culture, which dates from about 24,000 to 19,000 years ago. .
Contrary to expectations, the makers of the Gravettian tools came from two genetically distinct groups that inhabited western and eastern Europe about 10,000 years before the Ice Age peaked, Post says. Scholars have traditionally viewed Gravett tools as the products of a biologically homogeneous population that inhabited most of Europe.
“What we previously thought was one genetic origin in Europe turned out to be two,” says paleogeneticist Mateja Heidignac of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, who was not involved in the new study. And “it seems that western and southwestern Europe served [притулком від зледеніння] more than south-eastern Europe and Italy”.
Descendants of the western Gravettian population, which is linked to Solutrean artifacts and the remains of another ancient culture in western Europe that existed from about 19,000 to 14,000 years ago, survived the Ice Age before spreading northeast across Europe, the researchers say.
Further support for southwestern Europe as an Ice Age refuge comes from DNA extracted from a pair of fossil teeth belonging to a man associated with the Solutrean culture in southern Spain. This roughly 23,000-year-old adult was genetically similar to Western European hunter-gatherers who lived before and after the Last Glacial Maximum, Max Planck paleogeneticist Vanessa Villalba-Mouco and her colleagues, including Post, report March 1 in the journal Nature Ecology & Evolution .
Meanwhile, genetic evidence suggests that hunter-gatherers in modern-day Italy were replaced by people from the far east, probably from the Balkan region. These newcomers must have brought with them a special brand of stone artifacts previously found at Italian sites and elsewhere in Eastern Europe known as Epigravetti tools, Post says. Many archaeologists suspect that the Epigravettic wares were the products of hunter-gatherers who gathered in Italy during the peak of the Ice Age freeze.
But, Heidignac says, DNA analysis of the fossils of Ice Age Balkan people is needed to find out which groups moved through Italy and when those migrations took place.
Eventually, descendants of Ice Age migrants to Italy reached southern Italy and then western Europe by about 14,000 years ago, Post and colleagues say. Ancient DNA evidence suggests that during these journeys they left a significant genetic imprint on hunter-gatherers across Europe.