To understand how climate change impacted hunter-gatherer populations in Europe between 47,000 and 7,000 years ago, researchers from Germany, Italy, and the United States analyzed fossilized teeth for their morphological traits, according to a press release from the University of Tübingen. The study, published in the journal Science Advances, utilized the largest dataset of human fossils from Ice Age Europe to date.
The researchers examined various tooth characteristics, such as the number and shape of crown cusps, ridge and groove patterns on the chewing surface, and the presence or absence of wisdom teeth. These traits are heritable, allowing scientists to trace genetic relationships among Ice Age humans without relying on well-preserved ancient DNA.
“These traits are heritable, which means we can use them to trace genetic relationships among Ice Age humans without requiring well-preserved ancient DNA,” explains lead investigator Dr. Hannes Rathmann from the Senckenberg Centre for Human Evolution and Palaeoenvironment at the University of Tübingen.
Method Used Machine Learning Algorithm
Rathmann, in collaboration with colleagues from the University of Tübingen, the University of Ferrara in Italy, and New York University in the United States, developed a new method for analyzing the fossils based on a machine learning algorithm.
“Our new method, which we call Pheno-ABC, has enabled us to reconstruct complex prehistoric demographic events using morphological data. As far as we know, this has never been achieved before,” says co-first author Dr. Maria Teresa Vizzari from the University of Ferrara, who played a key role in developing the algorithm.
‘Drastic Demographic Change’
The study revealed that between 47,000 and 28,000 years ago, populations in Western and Eastern Europe were genetically well-connected. This period coincides with the arrival of the first modern humans in Europe during the last Ice Age, marking the beginning of the so-called Upper Paleolithic.
“This finding aligns with previous archaeological studies that identified widespread similarities in stone tools, hunting weapons, and portable art across different regions,” explains co-author Dr. Judith Beier from the DFG Center for Advanced Studies “Words, Bones, Genes, Tools” at the University of Tübingen.
However, during the Late Pleniglacial period, between 28,000 and 14,700 years ago, the researchers observed a significant reduction in population size and genetic diversity, with no genetic connections between Western and Eastern Europe.
“This drastic demographic change was likely driven by severe climate changes: Temperatures during this period dropped to the lowest values of the entire Upper Paleolithic, culminating in the Last Glacial Maximum, when ice sheets covered much of northern and central Europe,” said Rathmann.
“The deteriorating climate led to a shift from steppe to tundra landscapes, affecting the habitats of prey animals and, consequently, the hunter-gatherers who depended on them.”
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