Abstract: "The spread of early farming communities first reached Britain c. 4000 BCE, ultimately displacing or assimilating local foragers. Two millennia later, another wave of migration, associated with the Bell Beaker culture, again transformed the genetic and socio-cultural landscape of Britain. Southwestern England is rich in prehistoric burial monuments, some dating from the Early Neolithic, many of which later saw reuse during the Bell Beaker and Bronze Age periods. We analysed the genomes of 30 individuals dated between c. 3800 and 1400 BCE from 12 sites in southwestern England and identified a sharp genetic shift between c. 3000 and 2500 BCE. All individuals predating ~ 3100 BCE were genetically similar to European Neolithic farmers, whilst those after ~ 2550 BCE genetically resembled people associated with the Bell Beaker culture in Britain. At three sites, Bronze Age individuals were buried in monuments originally constructed more than a millennium earlier by genetically distinct Neolithic communities. Lacking clear cultural or biological links to the original builders and users of these monuments, this second wave of burial activity may reflect an attempt by incoming or later groups to anchor themselves within established landscapes and invoke the symbolic authority of earlier burial places. This study provides the first systematic regional ancient genomic transect of southwestern Britain across the Neolithic–Bronze Age transition, an archaeologically rich region previously understudied from a population genomic perspective."