Participants of this symposium held at the 21st Pacific Science Congress in Okinawa
Since the late 19th century, population history in the Japanese archipelago has attracted a great deal of interest. Substantial amounts of osteological, somatological, and genetic data have been accumulated, and a consensus theory was formed during the 1990’s. According to this theory, which is labeled as the dual structure model, the Japanese populations in historic times were formed through varying degrees of admixture between descendants of Jomon hunter-gatherers and Yayoi immigrants, who brought systematic wet-rice agriculture and metal-working technology into Japan. However, this understanding is still limited to events in a temporally and spatially narrow area, and our future goal should be directed toward the reconstruction of the entire population history of Homo sapiens over the wider area of Asia. In addition, attempts to integrate anthropological and archaeological evidence have so far been insufficient in modeling population history in much of this region. The primary goal of this symposium is to present a series of papers from leading authorities that synthesizes the current state of research regarding the biological and archaeological evidence for population histories in Asia with a longer timescale. The areas of focus include North, East, and Southeast Asia. Events in the Late Paleolithic period are discussed in addition to those in the Holocene.
The cranium and postcranial human remains found in Liujiang are the most complete and well preserved late Pleistocene human fossils ever found in south China. The original study put Liujiang into an early type of on-forming Mongoloids. However, many problems on Liujiang human fossils have been in debate. The Liujiang human fossils contain a complete cranium, right os coxae, sacrum, two femur fragments and several vertebras. Because there are no duplicated elements; the joint surfaces of adjacent bones articulate comfortably; and all the fossil bones have similar texture, these fossils are thought to represent the same individual. This unusual discovery makes us to calculate body size, body proportions and relative cranial capacity (encephalization quotient) for that individual rather more reliably. In the present study, based on the measurements of the Liujiang cranium and reconstructed pelvis, we calculated the stature, body breadth (biiliac breadth ), body weight, EQ index, body proportion for the individual. The body size and shape of the individual were further analysed. Our result indicates that the Liujiang individual has body proportions (body height relative to body breadth) typical of warm-adapted populations in the world. His encephalization quotient of 5.602 is bigger than those of other middle and late Pleistocene humans like Upper Cave and Jinniushan, and is closer to those of Minnatogawa 2 and modern human populations. The body weight 52.0 kg for Liujiang is also smaller than those of fossil humans living in higher latitude like Jinniushan, Upper Cave and Neanderthals, and closer to those of Minatogawa, KNM-ER3883 and KNM-ER3733 which all lived in warmer climate region. We believe that the body size, body proportions and relative cranial capacity (EQ) of Liujiang individual suggest his resemblance to the term Pleistocene and living humans.
The scandal of the forged Palaeolithic evidence, which broke on 5 November 2000, was followed over the next years by an intense debate about conceptual frameworks for research and dating. The fraudulent evidence almost completely compromised the basis for such a subdivision, the “Middle Palaeolithic” has now disappeared as a concept. One has to see it as a process from the “lithic industries before the blade technique” to the “emergence of blade industries,” uses the term “archaeology of the OIS (oxygen isotope stage) 3” for reference purposes, and evaluate the materials gathered so far.
Explicit evidence of human occupation that has based both on stratigraphy and morpho-typology of lithic artifacts is possible to trace back to the middle of OIS3 in the Japanese islands. Generally, lithic assemblages continue from uppermost Palaeolithic Layer down to the Layer X in Kanto area, but a single artifact is available beneath the Layer X. This suggests the first peopling of the Japanese islands connected with this time period. Some examples of the earliest archaeological sites such as Ushiromuta site in Miyazaki Prefecture, Shizume site in Kumamoto Prefecture, Takesa-nakahara and Tategahana sites in Nagano Prefecture, and Kanedori site in Iwate Prefecture, these are all belonging to the middle of OIS3. The earliest evidence of obsidian procurement from the Pacific island of Kozushima, southeast of Izu peninsula, was recognized in the Layer VII (Black band) dated as ca. 38000 cal BP. This implies a theoretical possibility of human migration from Asian mainland to the Japanese islands across the seawater in the middle of OIS3. Keywords: OIS3, Japanese islands, Blade industries.
Despite the abundance of the terminal Pleistocene archaeological sites in the Japanese archipelago, human skeletal remains which directly tell about the bearers of these Paleolithic cultures are rare. This is particularly true for the older sites which date back as old as 32,000-30,000 14C BP. The Yamashita-cho 1 human remains from Okinawa are the only exception to this situation, and thus hold a key to investigate the earliest settlers of the archipelago. Yamashita-cho 1 is from the Yamashita-cho 1 Cave in Naha City, near the southwestern corner of Okinawa. It consists of a femur and a tibia which belong to the same individual. These fossils were excavated in situ from the level slightly below the charcoal lens that yielded the 14C date of 32,100±1,000 BP, together with abundant bones of an extinct Cervus species, birds, fish, etc. Unfortunately, however, the juvenile state (6~7 years old) and thin layers of calcareous matrix attached to these lower limb bones have hampered extensive comparative analyses and detailed observations of their surface morphology. In this study, we first clean the attached matrix in order to obtain detailed morphological information from the specimens. A previous comparative study with recent Europeans, Pecos Pueblo Amerindians, and Pleistocene archaic and anatomically modern Homo suggested its affinities with modern humans with some archaic characteristics in mid-shaft cross-sectional properties. We evaluate the morphology of Yamachita-cho 1 primarily in Asian local evolutionary contexts. We compare surface morphology, external measurements, and cross-sectional properties of the specimens with those of the Holocene hunter-gatherers of Japan, the Jomon people.
In order to document spatio-temporal craniofacial variation in Northern and Southern Chinese Holocene populations, we conducted principal components analysis and significance testing utilizing 19 metric variables on adult male skulls from 13 Neolithic and 10 modern human populations. There is significant craniofacial variation between northern and southern (separated by Yangze River) Chinese populations from the Neolithic (except Neimeng) to the present day. For instance, in the Neolithic sample, the northern Chinese crania are characterized by greater upper facial height, orbital height, cranial index, cranial length?height index, upper facial index, orbital index, and orbital area, while the southern Chinese skulls are depicted by a longer head and a wider nasal index. In the modern day sample, southern crania are characterized by greater upper facial and nasal heights, upper facial index, facial size and orbital area vis-a-vis northern skulls. From the Neolithic to Bronze Age to present day, a series of microevolutionary processes can be discerned within the dataset of both northern and southern sample. Overall, the head becomes more globular. The orbits are narrower and higher. The nose is narrower and longer, while the cranial size and nasal area decreases. The maximum cranial length and orbital breadth decreases more significantly in southern Chinese populations, while the cranial length-height index decreases more significantly in northern Chinese samples. It is likely that Chinese Holocene craniofacial morphological variation is not only influenced by the environment, but also controlled by human evolutionary mechanisms.
The "Dual Structure" model is widely accepted in understanding the population history of Japan. According to this model, genes of the Yayoi immigrants from the continent hybrid with the indigenous Jomon people. Since the influence of the Yayoi culture had little impact on the northernmost Island of Japan, the Hokkaido Ainu are regarded as the direct descendants from the Jomon people.
On the other hand, population history of Southeast Asia is complex due to various migration processes and the inter-mixing of populations since prehistoric times. In general terms, Southeast Asia is thought to have been occupied by indigenous people (sometimes referred to as Australo-Melanesians), who exchanged genes with immigrants from North/East Asia leading to the formation of present-day Southeast Asians. This population history scenario for Southeast Asia is known as the “Two-Layer” model, which is linked with the dispersal of farming populations by archaeological data, and also supported by a wide range of genetic and linguistic data.
This hypothesis had not clearly supported by the limitation of prehistoric human remains, nevertheless, my multivariate analysis of dental data, made large scale comparisons using data from Northeast/Southeast Asian and Pacific groups, resulted in favor of this hypothesis, as well as the “Dual Structure” model. Furthermore, our recent excavations in Vietnam found the skeletal evidences to prove the existence of the indigenous and new colonization in this region. With the global perspective of population history, the "Dual Structure" model proposed for Japanese formation is regarded as a parallelism with the "Two Layer" hypothesis in Southeast Asia.
Since the whole human genome sequence became available in 2001, the strategy for human genetics has been changed dramatically. Mitochondrial genome (mtDNA) and Y-Chromosome are still the main tools for depicting phylogenetic relationships among human populations, while tons of autosomal markers (SNP: single nucleotide polymorphisms; STRP: short tandem repeat polymorphisms, etc.) being discovered through the world-wide whole genome surveys (for SNP, the international HapMap project published in 2005) are getting powerful weapons not only for probing fine genealogies, but also for detecting signals of positive selection, relating to environmental adaptation(s) in each geographic population.
Here I would review the trend of recent molecular-anthropological studies especially on East/Southeast Asians, involving my own previous studies. I and my collaborators have tried to find relationships between cultural/social factors and genetic variations, by investigating mtDNA, Y-STRP, and autosomal loci. The results of our researches have shown the obvious reflections of matrilocal/patrilocal residential patterns to genetic diversity 1), 2), and the strong evidence of natural selection related to alcohol metabolism that may concern with dietary behavior, life style, and endemic disease 3), 4), in East/Southeast Asians. Additionally, I will present the latest results of genetic analysis on people in Okinawa, Miyako, and Ishigaki islands, which is collaboration with Dr. Hajime Ishida, in University of Ryukus Faculty of Medicine.
1) Oota et al. (2001) Nat. Genet. 29: 20-21
2) Oota et al. (2002) AJPA 18: 146-153
3) Oota et al. (2004) Ann. Hum. Genet. 68: 93-109
4) Han et al. (in press) Am. J. Hum. Genet.
In this presentation, the author discusses the social background of the emergence, diffusion, and transformation of Jomon pottery from an archaeological viewpoint, mainly focusing on the Incipient Jomon period. On the Japanese Archipelago, the emergence of pottery dates as far back as the end of Pleistocene, this stage corresponds to the transitional period from the nomadic lifestyle of Paleolithic based on hunting to a sedentary lifestyle based on multiple resource exploitation, including hunting, gathering, and fishing; the characteristics of this period are often discussed in current Japanese archaeology. How and in what context did people on the Japanese Archipelago start to use pottery? Were they brought from outside the Archipelago by the immigrants, or were they invented independently? To answer this question, the author will first take an overview of the previous discussions, and then will examine the case examples in each region, such as Hokkaido, Honshu, and Kyushu. By comparing them with the cases in the surrounding area, it will be possible to show the outline of the pottery emergence process unique to the Japanese Archipelago.
Analysis of ancient DNA has become an increasingly important tool in elucidating the genetic information of ancient populations and their relationships. The Jomon people of Japan, one of the oldest pottery-makers in the world, are considered to have been remained undisturbed for several thousand years, therefore, genetic study of Jomon people can be expected to provide important information on the genetic features of the Upper Paleolithic Asian populations. In the present study, we examined the genealogy of the Jomon skeletons excavated in the northeastern part of Japan (Hokkaido and Tohoku region) by mitochondiral DNA analysis.
To assess the genetic affinities of the Jomon population, we detected the mtDNA haplogroup* of each individual. Haplogroups D1, G1, M7a, and N9b were mainly observed in the individuals, and N9b was the most predominant. The frequencies of the haplogroups were quite different from any modern populations reported previously. It indicates significantly different population histories for these two groups.
* A group of related mtDNA sequences descended from a single ancestral sequence is called a haplogroup. The relationships of each haplogroup are the key to reconstructing our genetic history.
From the 5th to 12th century A.D., the prehistoric Okhotsk culture was distributed about Sakhalin, the Okhotsk Sea coast of Hokkaido and the Kurile Islands. The people of the Okhotsk culture are believed to have developed a considerable maritime infrastructure.
Diversities of the Okhotsk cultural people and other prehistoric and historic populations were investigated in terns of nonmetric cranial traits. The incidences of the transverse zygomatic suture vestige in the Okhotsk series are high among the populations compared, while the frequency of the supraorbital foramen of the Okhotsk is as high as those of comparative samples except for the Ainu.
The MMD between the northern and eastern Okhotsk is small and insignificant. Interestingly, the Hokkaido Ainu is closer to the Okhotsk series than to the Jomon. The two-dimensional representation based on the MMD matrix showed that the Okhotsk and Ainu are relatively close to the Jomon and that prehistoric samples have generally close affinities to each other.
The Relethford and Blangero’s (1990) method proved the large Rii values (distances from the centroid) of the Jomon, Aluet, Hokkaido Ainu and eastern Okhotsk. On the other hand, the northern Okhotsk showed a greater observed variation than the expected variation. The positive residual may be resulted from a long-term gene flow from an outside or larger effective population size.
In a series of publications Walter Neves and co-workers have developed a model for the settlement of the America’s based on comparisons between early Holocene crania from Sumidouro Cave, and modern human crania from East Asia, Australia and the Pacific. The differences they observe between their Palaeo-Indian, and modern comparative series, suggest to them that North America was populated by two morphologically distinct, and temporally separated, migrations. The first of which were the descendants of a population from which Australian Aborigines had also derived, the second having East Asian cranial characteristics. As the size and shape of late Pleistocene and early Holocene skeletal series usually differ from contemporary populations in the same region, we have extended comparisons with the Sumidoro Cave series to include Paleolithic and Neolithic samples from China, the Jomon from Japan, and terminal Pleistocene Australians. These data provide little support for a common origin between the founding populations of Australia and the America’s.
Mesiodistal and buccolingual crown diameters were examined to describe and compare patterns of metric dental variation in 5 modern samples from the Ryukyu Island chain: Miyako, Ishigaki, Tokunoshima, and 2 samples from Okinawa Island. Principal component analysis applied to two separate datasets, raw measurement data and standardized (C-score) data, for 32 Asian and Pacific samples, including the 5 Ryukyu Islander series, produced an overall size factor and three shape factors (relative size of mesiodistal diameters against buccolingual diameters and two kinds of front-back polarity). Ryukyu Islanders share the similar features of crown dimensions with the predominant eastern Asians, characterized by mesodont dentition. Regarding shape factors, Ryukyu Islanders are distinctive among eastern Asian population groups on the one hand, and show diversity among themselves on the other hand. The inter-regional variation of Ryukyu Island groups estimated by Fst falls within the range of 4-6% of the total variance, greater than those of Arctic population samples (Aleuts and Eskimos). The average within-group variance of the Ryukyu Island series measured by R-matrix method (intra-regional variation) is compatible with those of East and Northeast Asians, Micronesians, and Polynesians. These findings suggest differential patterns of long-term gene flow from an outside source, geographical isolation, and genetic drift in each island of the Ryukyu Island chain, producing the morphological diversification of modern Ryukyu Islanders.
The “Jomon” people are prehistoric natives of the Japanese Islands, who subsisted from about 15,400 to 2,800 years ago. They have been shown by Suzuki (1982) and Brown (1999) to resemble Minatogawa I (a fossil human found in Okinawa dating back to about 18,250 or 16,600 years BP) and Liujiang (southern China; earlier than 67,000 or 101,000-227,000 yeas BP) much more than Upper Cave 101 (northern China; 29,000 to 34,000 years ago). But these are the results based only on cranial measurements. Baba and Endo (1982) and Baba (2002), observing postcranial skeletons, pointed out that the Minatogawa femora considerably differed from those of the Jomon as well as of Upper Cave and Liujiang in the degree of development of the linea aspera.
In the present preliminary study, two distance anayses were carried out using Mahalanobis' D2 from two points of view. One is an attempt to utilize both cranial and postcranial measurements for examining which is the closest to the Jomon of three Paleolithic Asian fossil specimens: Minatogawa I, Upper Cave 101, and Liujiang. The other trial is to expand the area to be searched for the ancestors of the Jomon, namely, to add Australian fossils, e.g., Keilor (southeastern Australia; terminal Pleistocene age, i.e., 12,000 or 6,800 years BP) in the analysis. As a result, the first analysis based on 15 cranial and 2 femoral measurements showed that the Jomon was closest to Minatogawa among the three Asian fossils, and the second based on 14 cranial measurements revealed that the Jomon resembled Keilor more than the three Asian fossils. Although the statistical significance for these analyses cannot be examined because of too samll sample size, they suggest that Australian populations should also be taken into consideration as candidates for the ancestors of the Jomon people.
The Minatogawa human remains, consisting of four partial skeletons and other isolated bones, were recovered in 1970 by Mr. Ohyama from Minatogawa limestone quarry, Yaese-cho, Okinawa, Japan. The remains date back to Late Pleistocene (ca. 20,000 years BP). The remains are well preserved and studied intensively elsewhere (i.e., Suzuki, 1982; Baba & Endo, 1982; Baba, 2000; Baba et al., 1998).
Minatogawa skeletons possess a robust ragged face with marked attachments for chewing muscles and a short stature (estimated as 153cm for a male) with slender upper limb bones and moderately thickened lower limb bones. These features demonstrate an adaptation to a narrow island in which Minatogawa people probably had a foraging life style in Paleolithic age to find tough and poor nutritious foods. Minatogawa people might have retained primitive morphological features in isolated Okinawa Island, because some of the characteristics, such as thickness of the skull vault (8 mm at bregma), narrowness of the postorbital region, and lateral projection of the supramastoid areas, are equivalent to those seen in archaic Homo.
General comparisons of observational morphological features suggest that, among several Late Pleistocene/Early Holocene human skulls found in East and Southeast Asia, the Minatogawa skulls are close to Wadjak and Jomon skulls and far from Upper Cave and Liujiang skulls. However, exact affinities of the Minatogawa skeletons are still unclear.