1. Department of Archaeology, University of Exeter, Exeter EX4 4QE, UK
2. BioArCh, Department of Archaeology, University of York, York YO10 5DD, UK
3. McDonald Institute for Archaeological Research, University of Cambridge, Cambridge CB2 3ER, UK
4. Section for Evolutionary Genomics, Globe Institute, University of Copenhagen, Copenhagen 1353, Denmark
5. Department of Archaeology, Memorial University of Newfoundland, St John's A1C 5S7, Canada
6. Earth, Atmospheric and Planetary Sciences Department, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
7. NERC Life Sciences Mass Spectrometry Facility, Scottish Universities Environmental Research Centre, East Kilbride G75 0QF, UK