1 Department of Zoology, University of Cambridge, Cambridge CB2 3EJ, UK; Lundbeck Foundation GeoGenetics Centre, GLOBE Institute, University of Copenhagen, Copenhagen K1350, Denmark; BGI, BGI-Shenzhen, Shanghai 201321, China; Group of Alpine Paleoecology and Human Adaptation (ALPHA), State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing 100101, China. Electronic address: yw502@cam.ac.uk.