Until recently, the academic consensus has been that the origin of Paleolithic settlers of Okinawa as typified by the human fossil Minatogawa Man I was likely to have been continental, since the human fossils of Minatogawa Man were considered to be most similar to those of the Liujiang Man. Recent research is veering in favour of more diverse origins for early settlers and in particular, a southern origin for the Okinawan human fossil – dubbed the Minatogawa Man I.
NHK broadcast news reported this past weekend (Sat, Feb 19, 2010) that new genetic studies have concluded that the ancestors of Paleolithic settlers in Okinawa were likely to be most closely related to the Australian human fossil known as Keilor with the implication that the earliest settlers of Japan and Australia may have shared the same ancestors (the ancestor of Minatogawa Man probably did not originate from Australia but from a common ancestor who migrated into the region.
In an advanced publication of the June 2009 paper “Typicality probabilities of Late Pleistocene human fossils from East Asia, Southeast Asia, and Australia: implications for the Jomon population in Japan” which reported research analysis based on 13 cranial measurements of five Pleistocene fossils compared with a Late/Final Jomon sample from the Tohoku district, which revealed that the Australian human fossil “Keilor” from Australia was more likely to be a member of the Jomon population descended from Minatogawa I from Okinawa, than the “Liujiang Man” from southern China.
An earlier paper “The Ancestors of the Jomon People Were Not Like Minatogawa I But Like Keilor?” (by researchers Hisao Baba and Yuji) had concluded that Australian specimens like Keilor and Lake Nitchie should also be taken into consideration as candidates for the Paleolithic ancestors of the Jomon people, (and the human fossils belonging to the Late/Final Jomon population) in addition to the Minatogawa and Liujiang materials. (The same researchers Hisao Baba and Yuji had earlier reported in another paper that their observational comparisons of morphological features of several Late Pleistocene/Early Holocene human skulls found in East and Southeast Asia, suggested that the Minatogawa skulls were closer to Wadjak and Jomon skulls, but farther from Upper Cave and Liujiang skulls.)
The new findings do not detract from the other findings the Paleolithic ancestors of the Jomon people also had a northern origin (southeastern Siberian). Another very recently published research paper Limbs and Twigs of the East Asian mtDNA Tree concluded that the presence of Y1 lineages among Ainu points to another migration route from the native Siberian populations to the northernmost populations of the Japanese islands in Hokkaido. The report also postulates that a founding migrating ancestor represented by the superhaplogroup trunk M had branched out into the rest of Eurasia, Southeast Asia, and Australia (all branches of M7 lineages).
Other recent studies based on craniofacial measurements have also suggest the northeastern Asian origin of the Jomon people.
For instance, the results of Hanihara and Ishida (2009)’s cranial studies comparing craniofacial data of Jomon samples and their contemporaries from various regions in the world, suggested that the Jomon ancestors of the northern part of Japan might have expanded southward to Honshu Island.
Earlier studies by Omoto and Saitou (1997), using gene frequency data of blood group, red cell enzyme, and serum protein systems from modern human populations, showed that Ainu and Ryukyuans, together with Hondo (main island) Japanese, are closer to Tibetans, Koreans, and Mongolians than to the other modern samples including southern Chinese and Southeast Asians, and asserted that the group represented by the Jomon people who gave rise to modern Ainu and probably also Ryukyuans has its origin in the Upper Paleolithic populations of Northeast Asia, not necessarily of Southeast Asia.
The findings of the paper “Y chromosome diversity in East Asia and Oceania” concluded that YAP lineages that are found in surviving M174 relic populations including Japan, Tibet and Andamanese (derived from M168 that also gave rise to M130 and M89 mutations) are representative of the early colonizers into Asia who likely originated in Africa, migrating along the coast of Indian subcontinent and dispersing during the lower sea levels of Pleistocene times. The paper postulates that the M168 lineages evolved into the M174 lineaged people who arrived in Japan with the Jomon people over 10,000 years ago. Over time however, the M174 lineage-populations in Japan (like those in the Andaman Islands and the Asian mainland became isolated geographically for a considerable time.
According to Asian Ancestry based on Studies of Y-DNA Variation: Part 1 Early origins’ roots from Africa and emergence in East Asia (2010), Haplogroups C and D (which along with hap E contains the YAP polymorphism) represent the Great Coastal Migration along southern Asia from Arabia to Southeast Asia before dispersing northwards to East Asia, are found at high frequency only in the populations of Tibet, the Jarawa and Onge people of the Andaman Islands and the Japanese Ainu. This source says that these surviving populations are descended from tribes that had dispersed in very early times (possibly ~50,000-66,000 years ago) traces of which have been subsequently erased by the expansion of other cultures. There are thought to be two ancestral sources: hunter-gatherers (represented by Haplogroup C1/SNP M217 – that is found in present-day Ainu and Sakhalin and Kamchatka populations) who crossed over around 30,000 years ago from the mainland via the northern landbridge from Sakhalin Island to northern Japan who formed the Jomon culture that expanded around ~20,000 years ago. Early founders from the Haplogroup C1 (SNP M8) lineages are thought to have entered Japan from the south around ~20,000 years ago because this haplogroup type is missing from Ainu in Hokkaido. The other early founding population is represented by Haplogroup D2 is thought to have entered Japan between 20,000-37,000 years ago (Haplogroup D is found in abundance only in Japan, in Tibet and in the south of China).
Recently, Adachi et al. (2009), using the frequency data of mtDNA haplogroups from two prehistoric Jomon, one ancient Okhotsk and 13 modern East Asian and Siberian populations, showed that the Jomon and Okhotsk people in northern Hokkaido were closest to Udegey from southeastern Siberia and, then, to Hokkaido Ainu. From these findings, they suggest that the Hokkaido Jomon people share part of their ancestral gene pool with southeastern Siberian populations. However, those findings only show the possibility of the Jomon being one of the ancestors of Udegey or Ainu, but do not necessarily indicate the Jomon people derived from a Paleolithic population in southeastern Siberia because it is unknown at present whether or not modern Siberians have the same DNA as that of Paleolithic Siberians.
References and further readings:
Typicality probabilities of Late Pleistocene human fossils from East Asia, Southeast Asia, and Australia: implications for the Jomon population in Japan. Yuji Mizoguchi. Anthropological Science (advance publication June 5, 2009) doi:10.1537/ase.090330
Retrieved from JOI JST.JSTAGE/ase/090330 ONLINE ISSN : 1348-8570
Limbs and Twigs of the East Asian mtDNA Tree Toomas Kivisild, et al. Molecular Biology and Evolution 19:1737-1751 (2002)
Asian Ancestry based on Studies of Y-DNA Variation: Part 1 Early origins’ roots from Africa and emergence in East Asia Genebased Tutorials, Jan 18, 2010
A Synopsis of Extant Y chromosome diversity in East Asia and Oceania. Peter Underhill
Y Chromosome Phylogeography in Asia: Inferring Haplogroup Origins and Polarity of Haplogroup Dispersion. Peter A. Underhill / In: Chap 19, Past Human Migrations in East Asia: Matching Archaeology, Linguistics and Genetics (Routledge Studies in the Early History If Asia). Alicia Sanchez-Mazas, Roger Blench et al.
Mitochondrial DNA analysis of Jomon skeletons from the Funadomari site, Hokkaido, and its implication for the origins of Native American. Adachi N., Shinoda K., Umetsu K., and Matsumura H. (2009) American Journal of Physical Anthropology, 138: 255–265
Minatogawa-jin no ichi-zuke [The positioning of Minatogawa man]. Baba H. (2002)
In: Minatogawa Fissha Iseki: Juyo Iseki
Kakunin Chosa Hokoku, Okinawa-ken Gushikami-son Kyoikuiinkai, Okinawa, pp. 121–131 (in Japanese).
Genetic origins of the Japanese: a partial support for the dual structure hypothesis Omoto K. and Saitou N. (1997) American Journal of Physical Anthropology, 102: 437–446