The Beaker Phenomenon and the Genomic Transformation of Northwest Europe

Bell Beaker pottery spread across western and central Europe beginning around 2750 BCE before disappearing between 2200–1800 BCE. The forces propelling its expansion are a matter of long-standing debate, with support for both cultural diffusion and migration. We present new genome-wide data from 400 Neolithic, Copper Age and Bronze Age Europeans, including 226 Beaker-associated individuals. We detected limited genetic affinity between Iberian and central European Beaker-associated individuals, and thus exclude migration as a significant mechanism of spread between these two regions. However, migration played a key role in the further dissemination of the Beaker Complex, a phenomenon we document most clearly in Britain, where we report data from 155 individuals who lived from 4000-800 BCE. British Neolithic farmers were genetically similar to contemporary populations in continental Europe and especially to Neolithic Iberians, indicating that a portion of their ancestry came from the Mediterranean rather than the Danubian route of farming expansion. From the beginning of the Beaker period and onwards, all British individuals harboured high proportions of Steppe-related ancestry and were most closely related to Beaker-associated individuals from the Lower Rhine area. The impact of this migration from the continent was profound, as we show that the spread of the Beaker Complex to Britain was associated with a replacement of ~90% of Britain's gene pool within a few hundred years, continuing the east-to-west expansion that had brought Steppe-related ancestry into central and northern Europe 400 years earlier.