1. Research Department of Genetics, Evolution, and Environment, University College London, Wolfson House, 4 Stephenson Way, London NW1 2HE, UK.
2. Arts and Humanities Research Council (AHRC) Centre for the Evolution of Cultural Diversity, Institute of Archaeology, University College London, 31–34 Gordon Square, London WC1H 0PY, UK.
3. Institute of Archaeology, University College London, 31–34 Gordon Square, London WC1H 0PY, UK.