Genetic and anthropometric studies on Japanese people

A common origin of Japanese has been proposed by a number of scholars since Arai Hakuseki first brought up the theory and Fujii Sadamoto, a pioneer of modern archaeology in Japan, also treated the issue in 1781.

Mark J. Hudson claimed that the main ethnic image of Japanese people was biologically and linguistically formed from 400 BCE to 1,200 CE.

[20][21] Regardless, both Northern and Southern Jōmon were craniofacially different from modern Mainland Japanese and had European-like features[22] and a 'well-defined and less flat upper face' respectively.

In any case, however, the study clarifies that "the estimate of ancestry profile cannot provide the definitive history of original migration, unless it will be further verified against historical evidence.

A 2017 study by Ulsan University analyzed a 7,700-year-old skull in Korea, finding evidence of genetic links to ancient populations, including those from Southeast Asia, such as Vietnamese people.

A mitochondrial DNA analysis revealed a genetic affinity between Koreans and Mongolians, indicating a shared Central Asian ancestry.

[48][page needed] Additionally, some scholars suggest that the Yayoi and their ancestors, the Wajin, may have originated from areas like Yunnan province in southern China.

[51] A September 2021 study published in the journal Science Advances proposed that the people of Japan bore genetic signatures from three ancient populations rather than just two as previously thought.

In essence, Japanese researchers claim that a tripartite theory is redundant as the genetical difference between Yayoi and Kofun groups is not significant enough and that the temporal discrepancy of the periods is minuscule.

[73] Ashley Montagu (1989) said that the "Mongoloid skull generally, whether Chinese or Japanese, has been rather more neotenized than the Caucasoid or European..."[75] Ann Kumar (1998) said that Michael Pietrusewsky (1992) said that, in a craniometric study, the cranial bones of Southeast Asians (Borneo, Vietnam, Sulu, Java, and Sulawesi etc.)

[74] He stated that a common origin of Northeast Asians could be traced and that they began entering the Japanese archipelago at the beginning of the Yayoi period.

[74] Park Dae-kyoon et al. (2001) said that distance analysis based on thirty-nine non-metric cranial traits showed that Koreans are closer craniometrically to Kazakhs and Mongols than to the populations in China and Japan.

Main migration routes into Japan during the Jōmon and Yayoi period
Glacier cover in Japan at the height of the last glaciation about 20,000 years ago
Phylogenetic tree of Ainu, Ryukyuan, Mainland Japanese, and other Asian ethnic groups. The Ainu and the Ryukyuan were clustered with 100% bootstrap probability, followed by the Mainland Japanese. The three populations in the Japanese archipelago clustered with the Korean with 100% bootstrap probability. [ 27 ] [ 28 ]
A population genomic PCA graph, showing the substructure of Eastern Asian populations, including analyzed Japanese Jōmon samples. Japanese people 's cluster (squares) is almost indistinguishable to the Korean people 's cluster (circles), while the Jōmon samples are shifted towards the Siberian cluster in a more distinct position. (2020) [ 35 ]
Ancestry profile of Japanese genetic clusters illustrating their genetic similarities to five mainland Asian populations [ 46 ]
Proposed tripartite styled genomic transitions in parallel with cultural transitions in pre- and protohistoric Japan. (2021)
According to Pietrusewsky, the group most similar to the Japanese cranial bones were the Koreans . Meanwhile, Chinese , Mongolians and Southeast Asians were distinguished from the Japanese. [ 74 ] (2010)