Mitochondrial genome variation in eastern Asia and the peopling of Japan

Abstract

thropological interest to us to know whether the modern Japanese are the result of an admixture between the Paleolithic– Neolithic aborigines and more recent immigrant populations, whether the indigenous population gradually evolved to give rise to the modern Japanese, with subsequent colonizations having strong cultural influences but only minor demographic impact, or even whether the late Neolithic waves entirely replaced the indigenous residents. Morphometric data obtained from the remains of Japanese Paleolithic people are more in accordance with a southern origin for these first immigrants. Subsequent morphological studies on modern indigenous (northern Ainu and southern Ryukyuans) and mainland Japanese favored an admixture model in which the former would be descendants of the Paleolithic Japanese and the latter derived from the Continental immigrants who gave rise to the Yayoi period (Hanihara 1991). Genetic analysis using classical markers assigned a definitive northern origin to the Upper Paleolithic inhabitants of Japan; but whereas some authors favored a homogeneous background for all modern Japanese (Nei 1995), others claimed that although Upper Paleolithic and Yayoi period immigrants had probably a northern Asian origin, they were genetically differentiated (Omoto and Saitou 1997). The application of molecular markers to define maternal and paternal lineages to the peopling of Japan confirmed the dual admixture model but added some interesting novelties. For example, the study of Y-chromosome markers led to the discovery of remarkable Korean and Tibetan influences on the Japanese population (Hammer and Horai 1995); and mtDNA HVS-I sequences also confirmed the Korean input (Horai et al.