Exploring models of human migration to the Japanese archipelago using genome-wide genetic data

The origins of people in the Japanese archipelago are of long-standing interest among anthropologists, archeologists, linguists, and historians studying the history of Japan. While the ‘dualstructure’ model proposed by Hanihara in 1991 has been considered the primary working hypothesis for three decades, recent advances in DNA typing and sequencing technologies provide an unprecedented amount of present-day and ancient human nuclear genome data, which enable us to refine or extend the dual-structure model. In this review, we summarize recent genome sequencing efforts of present-day and ancient people in Asia, mostly focusing on East Asia, and we discuss the possible migration routes and admixture patterns of Japanese ancestors. We also report on a meta-analysis we performed by compiling publicly available datasets to clarify the genetic relationships of present-day and ancient Japanese populations with surrounding populations. Because the ancient genetic data from the Japanese archipelago have not yet been fully analyzed, we have to corroborate models of prehistoric human movement using not only new genetic data but also linguistic and archeological data to reconstruct a more comprehensive history of the Japanese people.