House mouse Mus musculus dispersal in East Eurasia inferred from 98 newly determined complete mitochondrial genome sequences

The Eurasianhouse mouse Mus musculusis useful for tracing prehistorical human movement related to the spread of farming. We determined whole mitochondrial DNA (mtDNA) sequences (ca. 16,000 bp) of 98 wild-derived individuals of two subspecies, M. m. musculus (MUS) and M. m. castaneus (CAS). We revealed directional dispersals reaching as far asthe Japanese Archipelagofrom their homelands. Our phylogenetic analysis indicated that the eastward movement of MUS was characterised by five step-wise regional extension events: 1) broad spatial expansion into eastern Europe and the western part of western China, 2) dispersal to the eastern part of western China, 3) dispersal tonorthern China, 4) dispersal to the Korean Peninsula and 5) colonisation and expansion in the Japanese Archipelago. These events were estimated to have occurred during the last 2,000–18,000 years. The dispersal of CAS was characterised by three events: initial divergences(ca. 7,000–9,000 years ago) of haplogroups in northern most China and the eastern coast of India, followed by two population expansion events that likely originated from the Yangtze River basinto broad areas of South and Southeast Asia, including Sri Lanka, Bangladesh and Indonesia (ca. 4,000–6,000 years ago) and to Yunnan, southern China and the Japanese Archipelago (ca. 2,000–3,500). This study provides a solid framework for the spatiotemporal movementof the human-associated organisms in Holocene Eastern Eurasia using whole mtDNA sequences, reliable evolutionary rates and accurate branching patterns. The information obtained here contributes to the analysis of a variety of animals and plants associated with prehistoric human migration.