Extended Data Fig. 7: Early European Farmer (EEF) Ancestry through time in British regions.

The percentage of EEF ancestry is shown on the y axis, estimated with qpAdm following the approach of Patterson et al. (2022)¹⁷. The map shows the location of Bronze and Iron Age sites used for analysis. No genomes post-dating AD 250 were included. Samples are grouped by geography, with the “channel core” zone south of the River Thames subdivided into western (dark red), central (red) and eastern (yellow) regions. On the right-hand side, EEF ancestry is plotted against the date estimate for each genome and a rolling average line is shown (window size: 500 years, step size: 50 years). On the left-hand side, boxplots (Tukey’s method) show the spread of values for different 500-year time bins for each region. These bins are demarcated with grey dashed lines on the rolling average plot. Time bin date ranges are labelled with respect to the approximate archaeological period they centre on (EBA: Earlier Bronze Age, MBA: Middle Bronze Age, LBA: Later Bronze Age, EIA: Earlier Iron Age, LIA: Later Iron Age). Significant changes (Welch’s t-test, two-tailed; p < 0.05) between bins (n > 4) are highlighted with arrows. The period between 1000-875 BC is highlighted with a grey rectangle in the rolling average plots. This period has been previously associated with a population-wide increase in EEF ancestry in southern Britain¹⁷.