Overview[edit]

The relationship of Jōmon people to the modern Japanese (Yamato people), Ryukyuans, and Ainu is diverse and not well clarified. Morphological studies of dental variation and genetic studies suggest that the Jōmon people were of southern origin, while other studies of bacteria suggest that the Jōmon people were of possible northern origin.^[40][41] According to recent studies the contemporary Japanese people descended from a mixture of the ancient hunter-gatherer Jōmon and the Yayoi rice agriculturalists, and these two major ancestral groups came to Japan over different routes at different times.^{[42][43][44][45][46][47]} Recent studies however support a predominantly Yayoi ancestry for contemporary Japanese people.^[48]

Migration route of paternal haplogroup C.

The Jōmon people were not one homogenous ethnic group. According to Mitsuru Sakitani the Jōmon people are an admixture of two distinct haplogroups: A more ancient group from Central Asia(carriers of Y chromosome D1a), that were present since more than 35 000 years in Japan and a more recent group from Western Asia(carriers of Y chromosome type C1a) that migrated to Japan about 13 000 years ago.^[49] Mark J. Hudson of Nishikyushu University posits that Japan was settled by a proto-Mongoloid population in the Pleistocene who became the Jōmon, and that their features can be seen in the Ainu and Ryukyuan people.^[20] The Jōmon share several physical characteristics, such as relatively abundant body hair, with Europeans, but they derive from a separate lineage than modern Europeans.^[50]

According to Schmidt & Seguchi (2013)^[51] the prehistoric Jōmon people descended from a paleolithic populations of Siberia (Altai mountains region). Other cited scholars point out similarities between the Jōmon and various paleolithic and Bronze Age Siberians. There were likely multiple migrations into ancient Japan.^[51]

Genetics[edit]

Recent Y chromosome haplotype testing has led to the hypothesis that male haplogroups D-M55 and C1a1, which have been found in different percentages of samples of modern Japanese, Ryukyuan, and Ainu population, may reflect patrilineal descent from members of pre-Jōmon and Jōmon period of the Japanese Archipelago.^[43] Analysis of the mitochondrial DNA(mtDNA) of Jōmon skeletons from Hokkaido, Okinawa Island and Tōhoku region indicates that haplogroups N9b and M7amay reflect maternal Jōmon contribution to the modern Japanese mtDNA pool.^{[41][52][53][54][55]} In another study of ancient DNA published by the same authors in 2011, both the control and coding regions of mtDNA recovered from Jōmon skeletons excavated from the northernmost island of Japan, Hokkaido, were analyzed in detail, and 54 mtDNA samples were confidently assigned to relevant haplogroups. Haplogroups N9b, D4h2, G1b, and M7a were observed in these individuals.^[56] According to 2013 study, there was mtDNA sub-haplogroups inter-regional heterogeneity within the Jōmon people, specifically between studied Kantō, Hokkaido and Tōhoku Jōmon.^[41] According to 2011 study all major East Asian mtDNA lineages expanded before 10,000 YBP, except for two Japanese lineages D4b2b1 and M7a1a which population expanded around 7000 YBP unequivocally during the Jōmon Period (14–2.3 kya), thousands of years before intensive agriculture which imply that the use of abundant uncultivated food resources was the reason for population expansion and not agriculture.^[57]

A study about ancient Jomon aDNA from Sanganji shell mound in Tōhoku region in 2017, estimates that the modern mainland Japanese population probably inherit less than 20% of their DNA from Jōmon peoples' genomes.^[47] A genome research (Takahashi et al. 2019) shows that modern Japanese (Yamato) do not have much Jōmon ancestry at all. Nuclear genome analysis of Jōmon samples and modern Japanese samples show strong differences.^[48] Another recent estimate suggests about 10% Jōmon ancestry in modern Japanese.