Genetic analysis reveals an alternative explanation for the Jomon migration to Japan
It's long been assumed the Jomon people, who had inhabited the Japanese archipelago since around 16,000 years ago, had multiple lineages resulting from different migration routes. But new genetic evidence, including mitochondrial ...
This research puts greater emphasis on environmental and cultural factors being the possible drivers for the East and West of prehistoric Japan, respectively.
Rethinking Jomon population history
Most of what we know about the Jomon people of ancient Japan comes from pottery and other well-preserved materials. The more subtle history of the Jomon, such as details of the population and their movements, has been largely inferred from archaeological indicators, such as the number and distribution of archaeological sites.
However, despite large amounts of genetic data from Jomon remains being available, a comprehensive demographic history covering the entire Japanese archipelago has not been fully examined. Many studies have been conducted using DNA from the present-day Japanese population, but there are many confounding issues with those kinds of studies.
Researchers sought a more direct reconstruction of Jomon demographic history, in part to answer long-standing questions about the initial migration of the Jomon ancestry to the Japanese archipelago. It's known from prior studies looking at maternal mitochondrial DNA that there were two main lineages, loosely eastern and western. But it's unclear whether the split came before or after that initial migration.
Bayesian skyline plot. Using this analytical tool, the researchers could start with a simple set of assumptions, update it using the best DNA evidence available, and with those, estimate historic population changes with given uncertainties. Credit: Oota et al. CC-BY-ND
Sites used in the study. The 17 sites from which samples were examined for this study, with a blowout showing Chiba prefecture where the 13 newly sequenced individuals from Ichihara Jomon sites were located. Credit: Oota et al. CC-BY-ND
Phylogenetic network. A genetic network of Jomon mitochondrial genomes showing eastern (magenta) and western (green) groups across Japan, where branch marks show genetic mutations and each symbol represents one or more archaeological samples. Credit: Oota et al. CC-BY-ND