About a decade ago, when ancient DNA research began to gain traction, geneticists took hold that everything modern humans thought they knew about European peoples was wrong. The story was simpler than anyone expected. Europe was settled in just three large-scale migrations from the East.
Hunter-gatherers first appeared over 40,000 years ago. Then, 9,000 years ago during the Neolithic period, agricultural tribes expanded from Anatolia.
Finally, starting 5,000 years ago, the Cordware people expanded from the Russian steppes, beginning the Bronze Age in Europe. Cordware, named for its cord-like impression on ceramics, has unique genetic characteristics that have not previously existed in most parts of Europe. Genetically, most modern Europeans have some elements of each.
But this was always an oversimplification. Our new paper, produced in collaboration with colleagues in the United States and across Europe, focuses on some of the more complex interactions between ancient groups that occurred in northwestern Europe.
Our research elucidated the origins of prehistoric populations across Belgium and the Netherlands, and identified the population at the origin of the Late Neolithic migration to Britain, which may have led to the replacement of 90% of Britain’s Neolithic farmers.
Ancient DNA research already suggests a more nuanced picture. For example, when early Neolithic farmers first migrated to Europe, they had little interaction with local hunter-gatherers. As a result, although they now live far from their homeland, their genomes were still similar to those of their Anatolian ancestors.
But by 1,000 to 2,000 years later, they had absorbed significant local ancestors. Their hunter-gatherer ancestry has increased from just 10% to 30-40% in some regions. Clearly, hunter-gatherers did not disappear as farmers expanded.
northern wetlands
New research moves us further away from simple compositions. Almost ten years ago, our research group at the University of Huddersfield began a collaboration with palaeoecologist Professor John Stewart from Bournemouth University and archaeologists from the University of Liège in Belgium. We analyzed the genome of Neolithic human bones from the approximately 5,000-year-old Neolithic period excavated along the Meuse River in Belgium.
The study was part of a larger project led by Harvard University’s Professor David Reich and Dr. Iñigo Olalde, involving geneticists and archaeologists from across Western Europe. This widened the focus to further archaeological sites around the Lower Rhine-Meuse region, from the Late Hunter-Gatherer culture to the Bronze Age, including rivers as well as wetlands and coastal areas.
The fertile soil south of the Rhine Meuse marshes attracted pioneering Neolithic farmer settlers as early as 5,500 BC. However, the rich resources of northern wetlands were better suited to the hunter-gatherer lifestyle. Still, the results produced by our research student Alessandro Fichera in collaboration with Harvard University were a big surprise.
The genomes of Belgian Late Neolithic peoples contained at least 50% local hunter-gatherer ancestry, alongside expected Anatolian peasant ancestry. Discussing these results with my collaborators led to a “serendipity” moment. The same pattern emerged elsewhere in the region in similarly water-rich environments.
Remarkably, many of the early Neolithic Dutch samples discovered from further north, such as the Swifterbant culture, which famously maintained a hunter-gatherer economy alongside its adoption of agriculture, convey almost 100% hunter-gatherer ancestry.
Women’s role in agricultural extension
They then compared the Y chromosome and mitochondrial DNA, which trace male and female lineages, respectively. The Y chromosomes at the Belgian site were all characteristic of hunter-gatherers, but three-quarters of the mitochondrial DNA lineages came from Neolithic farmers living further south. The implication was clear. Agricultural know-how was brought by women to hunter-gatherer communities in the Water World.
Our findings support a version of the “frontier mobility” or “availability” model for Neolithic dissemination proposed by archaeologists Marek Zverebil and Peter Lawrie Conwy in the 1980s. They envisioned a contact zone between pioneer farming groups and hunter-gatherer regions arriving through “leapfrog colonization.”
In this model, the ‘availability’ stage involved cross-border contacts and small-scale movements, with the gradual formation of, for example, trade relations and marriage alliances. This is followed by a ‘substitution’ phase in which agriculture develops alongside foraging in hunter-gatherer areas, and finally an ‘integration’ phase in which agriculture becomes dominant.
Our findings suggest that the frontier was much more permeable to women than men, and that Neolithic women’s intermarriage into hunter-gatherer communities may have ultimately helped hunter-gatherers adopt agriculture full-time. Ultimately, the dominance of agriculture throughout Europe led to the extinction of any long-term agricultural alternative.
Perhaps this type of model could also apply to other parts of Europe, where evidence for how hunter-gatherer ancestry increased during the Late Neolithic is lacking. In any case, the fact that “more advanced” agrarian women married hunter-gatherer groups, contrary to many archaeologists’ expectations that hunter-gatherer women would “marry” here, suggests that perceptions need to change.
Beaker, Bronze Age, England
But about 4,600 years ago, people started moving again. Waves of new settlers, eventually pastoralists and farmers from the Russian steppes, began to penetrate the Rhine region in the form of a corded pottery culture. As more and more people migrated from the east, they transformed into what became known as the Bellbeaker culture.
Within a few centuries, the genetic landscape of the Rhine-Meuse region, including wetlands, was completely reshaped. Our colleagues found that less than 20% of the people who lived there 4,400 years ago trace their ancestry back to early farmers and hunter-gatherers. Today, at least 80% of their ancestors come from the steppes.
The Bellbeakers expanded rapidly and spread further in all directions, creating the Bronze Age of Central Europe. It has spread not only to central Europe, but also across the English Channel and across the UK, reaching as far north as the Orkney Islands.
The British farmers who had built Stonehenge for centuries seem to have all but disappeared, again for unknown reasons.
But have they really disappeared? Perhaps as we learn more about what happened from archeology and ancient DNA, this rather straightforward picture may become more nuanced.
