Genetics of hundreds of people between 5,000 and 45,000 years ago reveal how changing climates affected hunter-gatherers
About 45,000 years ago the first sapiens anatomically modern arrived in Europe. They were groups of hunter-gatherers who in the following millennia spread and left the first works of art, in the form of paintings and sculptures in caves and rock shelters on the continent. Today, scientists try to piece together the connections of those pre-agricultural cultureswhich began to disappear about 9,000 years ago, with the arrival of new populations and new sedentary ways of life from the East.
Genetics offer a valuable tool for approaching that period. This Wednesday two studies published in the journal Nature y Nature Ecology and Evolution They help to piece together the mosaic of the genetic history of early Europeans. The authors have analyzed information on the DNA of 356 individuals who lived between 45,000 and 5,200 years ago (including 116 unpublished samples) from 34 countries.
Among the novelties is the analysis of the first genomes of individuals belonging to two different hunter-gatherer cultures of southwestern Europe: Gravettian and Solutrean. The Gravettian industry was developed by two different groups that populated Europe about 30,000 years ago. The first, called Vstonice (referring to the oldest associated site), spanned Italy, the Czech Republic and Austria and descended from populations from present-day Russia. The second group, known as Fournol, inhabited southwestern Europe and descended from hunter-gathererss long established in the area.
But in addition to the genetics and the tools that have been found in the deposits, the climatic evolution of the planet provides a third key to understanding the connections between these populations. In particular, the period known as the Last Glacial Maximum (between 26,000 and 19,000 years ago, approximately) in which many regions became uninhabitableforcing groups of hunter-gatherers to retreat to refuges in the south of the continent.
A refuge in Granada
In France and the Iberian Peninsula, this period was accompanied by the development of flint tools of a new type (Solutrean), which the articles relate to people from the Fournol lineage. One of those refuges was in Granadaas the study published in Nature Ecology and Evolutionwhich describes the genetic profile of a person who lived 23,000 years ago, whose remains have been found in the Bad Lunch cave.
“I was in the right place (a climate refuge) at the right time (at the height of the cold peak of the Glacial Maximum),” he explains. Vanessa Villalba-Moucoresearcher at the Max Planck Institute for Evolutionary Anthropology, first author of the paper in Nature Ecology and Evolution and co-author of Nature. “For us is the irrefutable proof that in Iberia there is a genetic continuity during a period in which it is very difficult to find individuals, since half the continent remains uninhabited due to extreme weather conditions.
After the Glacial Maximum, the climate once again allowed population movements that would once again change the genetic footprint of Europeans. The surviving nuclei in western Europe ventured beyond their refugesforming a new genetic mixture in France, Belgium, Germany and Poland (called Goyet Q2), which is associated with the appearance of a new lithic technology: the Magdalenian.
In parallel, new populations from the Balkans appear on the Italian peninsula, a group called Villabruna, which in subsequent millennia will occupy part of Central Europe. A substitution that, according to the authors, could have been caused by an emigration forced by climatic changes. “At that time the climate warmed rapidly and considerably and forests spread across the entire European continent,” explains Johannes Krause, lead author of the study in Nature. “This may have prompted southerners to expand their habitat; It is possible that the previous settlers migrated north as their habitat, the mammoth steppe, dwindled.”
In any case, this replacement is not observed in Spain. “The genetic scenario that describes the cave of Malalmuerzo [continuidad gentica] it is completely different from what is seen in Italy”, Villalba-Mouco qualifies. However, in the north of the peninsula there is evidence of some contact with the Villabruna line. “We have the individual from the cave of El Mirn (Cantabria) who it lived 18,000 years ago and shows some Villabruna influence, although its majority lineage is the Goyet Q2, which spreads through Europe just after the Glacial Maximum”, he adds. “It is as if everything that reaches the peninsula arrived with much less forcewith a practically nil contribution in the South”.
In subsequent millennia, a new warming of the climate, called the Blling-Allerd period (14,800-12,900 years ago), once again prompted population movements that again modified the genetic diversity of Europeans. In fact, it is at this point that it appears one of the three main genetic ancestries found in many people todayinheritance of Villabruna and Goyet Q2.
The authors note that there would be no significant new genetic exchanges between hunter-gatherers on the continent for millennia after this, until agriculture began to spread from Anatolia around 8,000 years ago. “It is possible that the migration of the first farmers to Europe caused the withdrawal of hunter-gatherer populations to the far north of the continent.. At the same time, these two groups began to mix with each other, and continued to do so for about 3,000 years,” says Krause.
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