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Survivors of the Ice Age

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A genomic analysis conducted by an international team of scientists, including researchers from the Prehistory to Present Time: Culture, Environment, Anthropology (PACEA) laboratory, documents the migrations of hunter-gatherer populations during the last ice age over a period of 30,000 years. They found refuge in Western Europe but became extinct in the Italian peninsula.

Photo : Reconstruction of a Gravettian hunter-gatherer (32,000-24,000 y.a.), inspired by archaeological finds at the Arene Candide site in Italy © Tom Bjoerklund
Reconstruction of a Gravettian hunter-gatherer (32,000-24,000 y.a.), inspired by archaeological finds at the Arene Candide site in Italy © Tom Bjoerklund

Using the largest paleogenomic dataset for European hunter-gatherers, an international research team led by researchers from the University of Tübingen and the Senckenberg Centre for Human Evolution and the Paleoenvironment, Peking University and the Max Planck Institute for Evolutionary Anthropology in Leipzig in Germany, in collaboration with scientists from the Bordeaux laboratory Prehistory to Present Time: Culture, Environment, Anthropology (PACEA - in French), has rewritten part of European genetic history in a paper published in the journal Nature.

The team analysed the genomes of 356 prehistoric hunter-gatherers from different archaeological cultures, including data from 116 individuals from 14 different countries in Europe and Central Asia. It had already been shown that populations of Homo sapiens began to spread across Eurasia around 45,000 years ago. However, these early waves of settlement did not contribute to the genetic diversity of subsequent populations in Europe. The new study focuses on individuals who lived between 35,000 and 5,000 years ago and who are, at least in part, the ancestors of the populations living in Western Eurasia today. In addition, it describes - for the first time - the genomes of individuals who lived during the Last Glacial Maximum, the coldest phase of the last ice age, around 25,000 years ago.

Climatic refuge or cul-de-sac?

Surprisingly, the research team found that the populations associated with the Gravettian culture, which settled on the European continent between 32,000 and 24,000 years ago, were not closely related to each other. They were linked by a common archaeological culture using similar weapons and producing comparable furniture art. Genetically, the populations of Western and South-Western Europe (present-day France and Iberian Peninsula) differed from contemporary populations in Central and Southern Europe (present-day Czech Republic and Italy). The genetic heritage of the hunter-gatherers of this period who lived in South-Western Europe is found continuously for at least 20,000 years. Indeed, their descendants, associated with the Solutrean and Magdalenian cultures, remained in South-Western Europe during the coldest period of the last ice age (between 25,000 and 19,000 years ago) before spreading north-eastwards to the rest of Europe.

From the Maszycka cave in southern Poland: a human jaw, bones and antlers from the Magdalenian culture, which was widespread in large parts of Europe 19,000 - 14,000 years ago © Agnieszka Susuł, Paweł Iwaszko, Dawid Piątkiewicz, Archaeological Museum Krakow
From the Maszycka cave in southern Poland: a human jaw, bones and antlers from the Magdalenian culture, which was widespread in large parts of Europe 19,000 - 14,000 years ago © Agnieszka Susuł, Paweł Iwaszko, Dawid Piątkiewicz, Archaeological Museum Krakow

"With these findings, for the first time we can directly support the hypothesis that populations found refuge in South-Western Europe during the coldest phase of the last ice age because of the more favourable climatic conditions there," says University of Tübingen researcher Cosimo Posth. As for the Italian peninsula, it was previously considered another refuge for human populations during the Last Glacial Maximum. However, the research team found no evidence for this, on the contrary: the hunter-gatherer populations associated with the Gravettian culture that lived in Central and Southern Europe do not seem to have left any descendants after the Last Glacial Maximum. A new gene pool settled in these areas instead.

Large-scale genetic replacement

The analysed genomes also show that descendants of these ancient Epigravettian inhabitants of the Italian peninsula spread across Europe around 14,000 years ago, replacing populations associated with the Magdalenian culture. The research team describes a large-scale genetic replacement that may have been caused, in part, by climatic changes that triggered these migrations. "At that time, the climate warmed rapidly and dramatically, and forests expanded across the European continent. This may have prompted the southerners to migrate northwards as the habitat to which they were adapted, the 'mammoth steppe', diminished," explains German archaeogeneticist Johannes Krause. Subsequently, the results show that there was no genetic exchange between contemporary hunter-gatherer populations in Western and Eastern Europe for almost 6,000 years. Interactions between Central and Eastern European populations were detected again 8,000 years ago. "At that time, hunter-gatherers of different ancestry and appearance began to mix. They differed in many physical characteristics, including skin and eye colour," says researcher He Yu.

Bibliographic references

Posth, C., Yu, H., Ghalichi, A., Rougier, H., Crevecoeur, I., Huang, Y., et al. (in press). Paleogenomics of upper paleolithic to neolithic European hunter-gatherers. Nature, Doi: https://doi.org/10.1038/s41586-023-05726-0

Researcher contacts

  • Isabelle Crevecoeur

    Paleoanthropologist at the PACEA laboratory

    isabelle.crevecoeur%40u-bordeaux.fr

  • Bruno Maureille

    Paleoanthropologist at the PACEA laboratory

    bruno.maureille%40u-bordeaux.fr