We acknowledge the ancient people whose skeletal samples were studied, the Aleut Corporation, the Aleutians Pribilof Islands Association, and the Chaluka Corporation for granting permissions to conduct genetic analyses on the eastern Aleutians. We thank the staff at the Smithsonian Institution’s National Museum of Natural History for facilitating the sample collection; the McGrath Native Village Council and MTNT Ltd for granting permissions to conduct genetic analyses on the Tochak McGrath remains; J. Clark, who performed biological age estimates on these remains; the research participants in Alaska (Genetics of Alaskan North Slope (GeANS) project funded by NSF OPP-0732857) and West Siberia who donated samples for genome-wide analysis; J. B. Coltrain for sharing data on stable isotopes; and J. W. Ives, J. Tackney, L. Norman, and K. TallBear for comments on earlier drafts of this paper. Sample collection and the initial molecular, isotopic, and accelerator mass spectrometry (AMS) 14C dating of the samples described here were funded by National Science Foundation Office of Polar Program grants OPP-9726126, OPP-9974623, and OPP-0327641; the Natural Sciences and Engineering Research Council of Canada; and the Wenner-Gren Foundation for Anthropological Research (6364). This work was supported by the Czech Ministry of Education, Youth and Sports from the project ‘IT4Innovations National Supercomputing Center – LM2015070’. P.F., P.C., O.F., and N.E.A. were supported by the Institutional Development Program of the University of Ostrava; P.F. and P.C. were supported by the EU Operational Programme ‘Research and Development for Innovations’ (CZ.1.05/2.1.00/19.0388) and P.C. was also supported by the Statutory City of Ostrava (0924/2016/ŠaS) and the Moravian-Silesian Region (01211/2016/RRC); P.S. was funded by the Francis Crick Institute, which receives its core funding from Cancer Research UK (FC001595), the UK Medical Research Council (FC001595), and the Wellcome Trust (FC001595); D.R. was funded by NSF HOMINID (grant BCS-1032255), NIH (NIGMS), the Allen Discovery Center of the Paul Allen Foundation (grant GM100233), and is an Investigator of the Howard Hughes Medical Institute; D.A.B. was supported by a Norman Hackerman Advanced Research Program grant from the Texas Higher Education Coordinating Board; AMS 14C work at Pennsylvania State University by D.J.K. and B.J.C was funded by the NSF Archaeometry programme (BCS-1460369); and C.J., T.C.L., J.K., and S.S. were supported by the Max Planck Society.

Reviewer information

Nature thanks Carles Lalueza-Fox, John Lindo and the other anonymous reviewer(s) for their contribution to the peer review of this work.