Role of Genetic Drift Among Ryukyu Islanders Populations in Japan

Genetic drift may have shaped the differences in demographic history observed between Ryukyu Islander populations, a new study suggests. The Ryuku Islands form the southernmost part of the Japanese Archipelago and themselves can be grouped into the Amami Islands, the Okinawa Islands, the Miyako Islands, and the Yaeyama Islands. In the Journal of Human Genetics, researchers from the University of the Ryukyus examine the genetic population structure of Ryuku Islanders using whole-genome sequencing data from Okinawa and Miyako islanders alongside publicly available East and Southeast Asian datasets. From this, they noted a genetic difference between Okinawa and Miyako islanders, though they find that this difference is likely due to genetic drift rather than any differences in gene flow to the two island groups from the main islands of Japan or from Taiwan. "[W]e identified a genetic cline among Ryukyu Islanders that was shaped primarily by genetic drift that occurred in a subpopulation of the Miyako Islands and by interregional migrations," the researchers write. They add, though, that there are still unanswered questions about the population history of the Ryukyu Islands, such as the origin of the Paleolithic populations, which they say could be answered through additional ancient and modern genomic analysis.