Editing Ryukyuans (section)

===Anthropological studies===
The comparative studies on the dental diversity also showed long-term gene flow from outside source (main-island Honshu and from the southern part of East Asia), long-term isolation, and genetic drift which produced the morphological diversification of the modern Ryukyuans. However, the analysis contradicts the idea of homogeneity among the Jōmon people and a closer affinity between the Ainu and the Ryukyuans.<ref>{{cite journal |author1=Takashi Toma |author2=Tsunehiko Hanihara |author3=Hajime Sunakawa |author4=Kuniaki Haneji |author5=Hajime Ishida |date=2007 |title=Metric dental diversity of Ryukyu Islanders: a comparative study among Ryukyu and other Asian populations |journal=Anthropological Science |volume=115 |issue=2 |pages=119–131 |doi=10.1537/ase.061219 |doi-access=free }}</ref><ref name="Timothy2012"/><ref>{{cite journal |author1=Kuniaki Haneji |author2=Tsunehiko Hanihara |author3=Hajime Sunakawa |author4=Takashi Toma |author5=Hajime Ishida |date=2007 |title=Non-metric dental variation of Sakishima Islanders, Okinawa, Japan: a comparative study among Sakishima and neighboring populations |journal=Anthropological Science |volume=115 |issue=1 |pages=35–45 |doi=10.1537/ase.060206 |doi-access=free }}</ref><ref>{{cite journal |author=Eri Miyazato|display-authors=etal|date=July 2014 |title=Comparative Analysis of Facial Morphology Between Okinawa Islanders and Mainland Japanese Using Three-Dimensional Images |url=https://researchonline.ljmu.ac.uk/id/eprint/7359/7/Comparative_analysis_of_facial_morphology_between_Okinawa_Islanders_and_mainland_Japanese_using_three-dimensional_images..pdf |journal=[[American Journal of Human Biology]] |volume=26 |issue=4 |pages=538–548 |access-date=7 February 2017 |doi=10.1002/ajhb.22560|pmid=24838439 |s2cid=12061839}}</ref><ref>{{cite journal |author=Tadashi Yamauchi|display-authors=etal|date=2016 |title=A comparative study of craniofacial measurements between Ryukyuan and mainland Japanese females using lateral cephalometric images |journal=Anthropological Science |volume=124 |issue=1 |pages=45–62 |doi=10.1537/ase.151206 |doi-access=free |hdl=20.500.12000/46965 |hdl-access=free }}</ref><ref>{{cite journal |author=Daisuke Miyamori|display-authors=etal|date=2015 |title=Tracing Jomon and Yayoi ancestries in Japan using ALDH2 and JC virus genotype distributions |journal=Investigative Genetics |volume=6 |issue=14 |page=14 |doi=10.1186/s13323-015-0031-1 |pmid=26719788 |pmc=4696161 |doi-access=free }}</ref><ref>{{cite journal |author=Kae Koganebuchi|display-authors=etal|date=2016 |title=The allele frequency of ALDH2*Glu504Lys and ADH1B*Arg47His for the Ryukyu islanders and their history of expansion among East Asians |journal=[[American Journal of Human Biology]] |doi=10.1002/ajhb.22933 |pmid=27801545 |volume=29 |issue=2 |page=e22933|s2cid=28167073}}</ref> A recent craniometric study shows that the Ryukyuans are closely related to the Yamato people and their common main ancestors, the [[Yayoi people]]. The Ryukyuans differ strongly from the [[Ainu people]], which, according to the authors, is a strong evidence for the heterogeneity of the Jōmon period population.<ref>{{Cite journal|last=Pietrusewsky|first=Michael|date=2017|title=A multivariate analysis of measurements recorded in early and more modern crania from East Asia and Southeast Asia|journal=The Journal of the International Union for Quaternary Research |citeseerx=10.1.1.380.1457}}</ref>

As previous morphological studies, such as Kondo et al. 2017, the genetic and morphological analysis by Watanabe et al. 2021, confirmed that the Jōmon period people were heterogeneous and differed from each other depending on the region. A North-to-South cline was detected, with the southern Jōmon of [[Kyushu]], [[Shikoku]] and southwestern [[Honshu]] being closer to contemporary [[East Asian people]], while the northern Jōmon of [[Hokkaido]] and [[Tohoku]] being more distant from East Asians. The study results confirmed the "dual-structure theory" regarding the origin of modern Japanese and Ryukyuans, but found that noteworthy amounts of East Asian associated alleles were already present within the Jōmon period people prior to the migration of continental East Asians during the Yayoi period. The southern Jōmon, which are ancestral to the Ryukyuans, were anthropologically most similar to modern day East Asians and differed from Jōmon period samples of Hokkaido quite significantly.<ref name="biorxiv.org">{{Cite journal |last1=Watanabe |first1=Yusuke |last2=Ohashi |first2=Jun |date=2021-03-08 |title=Comprehensive analysis of Japanese archipelago population history by detecting ancestry-marker polymorphisms without using ancient DNA data |url=https://www.biorxiv.org/content/10.1101/2020.12.07.414037v2 |journal=bioRxiv |language=en |pages=2020.12.07.414037 |doi=10.1101/2020.12.07.414037 |s2cid=229293389}}</ref>{{failed verification|date=September 2023|reason=This specific source does not mention Southern Jomon, or that "the southern Jōmon, which are ancestral to the Ryukyuans, were anthropologically most similar to modern day East Asians and differed from Jōmon period samples of Hokkaido quite significantly."}}