T. Wakebe, corresponding author. e-mail: wakebe@net.nagasaki-u.ac.jp phone: +81-095-849-7022; fax: +81-095-849-7024 Published online 29 June 2004 in J-STAGE (www.jstage.jst.go.jp) DOI: 10.1537/ase.00100
Index
Introduction
Materials and Methods
Materials
Metrical analysis
Nonmetrical analysis
Results
Cranial measurements
Incidences of nonmetric cranial traits
Discussion
Regionality of modern female populations in the Japanese archipelago
Morphological characteristics of female crania in the northwestern Kyushu Japanese
Relation between modern and Yayoi people in the northwestern Kyushu area
Acknowledgments
References

Introduction

Numerous morphological studies—both metric and nonmetric—of crania from the Japanese archipelago have been reported (e.g. Koganei, 1893; Hasebe, 1917; Miyamoto, 1924; Morita, 1950; Yamaguchi, 1973, 1978; Dodo, 1974; Mouri, 1976; K. Hanihara, 1984). In recent years, detailed comparative studies of Ryukyuan crania have also been published by Dodo and others (Dodo et al., 1998, 2000; Dodo, 2001). Because morphological regionality is closely related to the lineage history of populations, clarifying the morphological characteristics of the modern peoples in each area of Japan is useful in the study of the origin and formation of the Japanese.

In this study we examined modern female crania from the northwestern Kyushu area, i.e. the northwest region of Kyushu Island, including many islets (Figure 1). The people of the Yayoi period (ca. 300 BC to 300 AD) in this area inherited some morphological characteristics from the people of the Jomon period (ca. 10,000 BC to 300 BC), who had a low, wide face and short stature (Naito, 1971, 1981, 1984). However, the Yayoi people in neighboring northern Kyushu area had a markedly higher face and taller stature than the Jomon (Kanaseki, 1956, 1959, 1966; Nakahashi et al., 1985; Nakahashi and Nagai, 1989; Nakahashi, 1993). Therefore the Yayoi people of the northern Kyushu area are considered to have been strongly influenced genetically by immigrants from the Asian continent or their descendants. It is widely considered—based on many morphological and genetic studies—that people of continental lineage were influential in the formation of the modern Japanese (e.g. Mouri, 1986, 1988; Ossenberg, 1986; Dodo, 1987; Dodo and Ishida, 1988, 1990, 1992; T. Hanihara, 1989, 1991; Kozintsev, 1990; Yamaguchi, 1990; K. Hanihara, 1991, 1993; Nakahashi, 1993; Omoto, 1995; Omoto and Saito, 1997; Ikeda, 1998).


View Details		Figure 1.
Map showing the location of the northwestern Kyushu area and samples from other areas used in the present study.


Noda (1993) morphologically investigated male crania to ascertain whether modern males in the northwestern Kyushu area had inherited the characteristics of Yayoi males, and concluded—because of similarities such as a lower cranial vault, a lower face, and a lower orbit—that the modern males of this area show influence of Yayoi males from the same area. However, the morphological characteristics of modern female crania from northwestern Kyushu have not been clarified. Cranial morphological studies have mainly been carried out using male or mixed samples, but little detailed work has been performed on female samples. However, there have been some cases of excavation of exclusively female human skeletal remains from ancient sites. Also, lineage analyses using mitochondrial DNA (which is matrilinearly inherited) in both ancient and modern Japanese have increased in recent years (Horai et al., 1989, 1991; Shi-noda and Kunisada, 1990, 1994; Kurosaki et al., 1993; Oota et al., 1995; Shinoda and Kanai, 1999). Therefore we considered it necessary to clarify the lineage relations of not only males but also females.

This study employed standard metrical and nonmetrical methods for comparative analysis of modern and earlier female crania. We attempted to clarify metric and nonmetric characteristics of the modern female crania from the northwestern Kyushu area and to estimate their lineage relationships by analyzing and comparing modern Japanese, Ryukyuans, Ainu, Koreans, Chinese, Yayoi, and Jomon female crania, along with comparisons and consideration of previous findings based on male crania.


Materials and Methods

Materials

The 204 female crania stored at the Nagasaki University Graduate School of Biomedical Sciences were examined. These were crania of people born between 1866 and 1937 in Nagasaki prefecture, and their birth and death dates and domiciles were documented. Comparative samples used in this study are shown in Table 1. For direct comparisons of measurements and indices in metrical analyses, northwestern Kyushu, northern Kyushu, Kinki, and Kanto Japanese, Hokkaido Ainu, northwestern Kyushu Yayoi, northern Kyushu Yayoi, and Tsukumo Jomon samples were used. For direct comparisons of trait incidences in the nonmetrical analyses, northwestern Kyushu, northern Kyushu, Kinki, and Kanto–Tohoku Japanese, Hokkaido Ainu, northwestern Kyushu Yayoi, northern Kyushu Yayoi, and Jomon samples were used. For multivariate analyses, all samples were used in both metrical and nonmetrical comparisons.



Metrical analysis

The 41 cranial measurements and 16 indices shown in Appendix 1 were measured according to Martin’s methods (Bräuer, 1988; Baba, 1991), and 17 measurements and 9 indices shown in Table 2 were used in the analyses. It has been reported that the method of measuring upper facial height varies between researchers, and this affects the results of analysis (Dodo, 2001). In this study, using Martin’s methods, the distance between the ‘nasion’ and the ‘alveolare’ was measured. The upper facial height of the northwestern Kyushu Yayoi (Naito, 1971) was corrected by adding 2.0 mm (Dodo, 2001) because it had been measured between the ‘nasion’ and the ‘prosthion’. The upper facial indices of the northwestern Kyushu Yayoi were also corrected by a proportional amount.



Student’s t-test was performed to test the significance of differences in the measurements. For the indices, the normality of distribution was examined in the large sample of northwestern Kyushu Japanese. As a result, the null hypothesis of normal distribution could not be rejected at the 5% level, except in the upper facial (K) and nasal indices. Student’s t-test was used with the other indices. Furthermore, to compare visually the various measurements, Mollison’s deviation curves were prepared. For multivariate analyses, principal component analysis and cluster analysis using Pen-rose’s shape distances were performed in an attempt to assess biological lineage relations among the samples (Constandse-Westermann, 1972).

Nonmetrical analysis

The 22 nonmetric cranial traits shown in Appendix 2 were assessed according to Dodo’s criteria (Dodo, 1974, 1975, 1986). However, only 17 traits were used in the analyses because biasterionic suture vestige, foramen of Vesalius, clinoid bridging, juglar foramen bridging, and sagittal sinus groove left were not investigated in the Kinki and Hokuriku Japanese, and in the Amami–Okinawa islanders. The incidence of each trait was analyzed by a χ2 test or Fisher’s exact probability test. For multivariate analyses, Smith’s mean measure of divergence (MMD) was calculated in order to assess biological distances among the samples (Sjøvold, 1973), and principal coordinate analysis was then performed. The statistical tests and multivariate analyses were processed by a computer software package from Kyoritu-shuppan Inc. (Tanaka et al., 1984) and Excel Multivariate Analysis version 4.0 (Esumi Inc., 2002).


Results

Cranial measurements

The 41 measurements and 16 indices for the modern female crania of the northwestern Kyushu Japanese are shown in Appendix 1.

Neurocranium

The neurocrania of the northwestern Kyushu female Japanese were shorter in maximum cranial length, narrower in maximum cranial breadth, and higher in basion–bregma height than those of the northern Kyushu Yayoi, northwestern Kyushu Yayoi, and Tsukumo Jomon. The measurements of the four modern Japanese series were comparable overall, except that the Kinki Japanese had somewhat shorter maximum cranial length and wider maximum cranial breadth. Among these samples, the northwestern Kyushu Japanese was closest to the northern Kyushu Japanese. The cranial-type classifications based on three cranial indices, the length–breadth, length–height, and breadth–height indices, were mesocranic, hypsicranic, and acrocranic in both Japanese groups.

Facial skeleton

The facial skeletons of the northwestern Kyushu and other modern Japanese were narrower in breadth measurements (Martin’s no. 45, 46, 51, and 54), greater in height measurements (Martin’s no. 47, 48, 52, and 55), larger in facial, upper facial, and orbital indices, and smaller in the nasal index than those of the Hokkaido Ainu, northern Kyushu Yayoi, northwestern Kyushu Yayoi, and Tsukumo Jomon, except for nasal breadth of the Hokkaido Ainu, and facial, upper facial, orbital, and nasal heights of the northern Kyushu Yayoi. Moreover, the northwestern Kyushu Japanese were taller than other modern Japanese women.

Mollison’s deviation curves

As shown in Figure 2, Mollison’s deviation curves, with the northwestern Kyushu Japanese as the baseline, depict the morphological relationships of the various groups well. The curves of the northern Kyushu, Kinki, and Kanto Japanese did not deviate much from the baseline, indicating that these groups are morphologically close to the northwestern Kyushu Japanese. On the other hand, the curves of the Hokkaido Ainu, northern Kyushu Yayoi, northwestern Kyushu Yayoi, and Tsukumo Jomon deviated far from the baseline. In particular, the amplitude of curves for the northwestern Kyushu Yayoi and Tsukumo Jomon was large, indicating that there were large morphological differences with the northwestern Kyushu Japanese.


View Details		Figure 2.
Mollison’s deviation curves of the female cranial measurements and indices, using the northwestern Kyushu Japanese as the baseline of comparison.


Multivariate analyses

Figure 3 shows the results of principal component analysis for 15 samples using the mean values of ten cranial measurements (Martin’s no. 1, 8, 17, 40, 45, 48, 51, 52, 54, and 55), which are generally used, with no duplication of length, height, and breadth measurements in the neurocranial, facial, orbital, and nasal parts. The northwestern Kyushu Japanese had a different first principal component score from the Tsukumo Jomon, northwestern Kyushu Yayoi, northern Kyushu Yayoi, Hokkaido Ainu, Miyako Islanders, and Amami–Okinawa Islanders; and they had a different second principal component score from the Chinese and Hokuriku Japanese. The northwestern Kyushu Japanese had a score similar to the other modern Japanese and Koreans, and had the closest score to the Kanto and northern Kyushu Japanese. Table 3 shows Penrose’s shape distances calculated from ten mean values used in the principal component analysis. The distances show that the northwestern Kyushu Japanese were closest to the northern Kyushu Japanese, followed by the Kanto Japanese and Central Kyushu Japanese, in that order. Conversely, the northwestern Kyushu Japanese were markedly distant from the Tsukumo Jomon and northwestern Kyushu Yayoi, and were also distant from the Hokkaido Ainu, Miyako Islanders, and Amami–Okinawa Islanders. Figure 4 shows the results of cluster analysis using the group average method based on the Penrose’s shape distances. The 15 groups were divided into two large clusters: one cluster consisted of the Tsukumo Jomon and northwestern Kyushu Yayoi, while the other cluster contained the remaining 13 groups. The latter cluster was further divided into a cluster consisting of the Hokkaido Ainu and the Amami–Okinawa and Miyako Islanders, and a cluster containing the other ten groups. Of those ten groups, the northwestern Kyushu, northern Kyushu, central Kyushu and Tohoku Japanese formed a cluster, and this cluster merged with a cluster comprising the Kinki Japanese, Kanto Japanese, and Koreans, and then with the Hokuriku Japanese, the northern Kyushu Yayoi, and Chinese, in that order.


View Details		Figure 3.
Scatter diagram of first and second principal component scores calculated from 10 cranial measurements of 15 female cranial series. With the first principal component, strong positive factors are bizygomatic breadth, maximum cranial breadth and maximum cranial length, while strong negative factors are upper facial height and basion-bregma height. In the second principal component, the positive factor is the whole size of the cranium. Abbreviations are the same as those given in the footnote of Table 3.





View Details		Figure 4.
Group average clustering analysis based on the Penrose’s shape distances matrix shown in the Table 3. Abbreviations are the same as those given in the footnote of Table 3.






Incidences of nonmetric cranial traits

The incidences of 22 nonmetric traits for the modern female crania of the northwestern Kyushu Japanese are shown in Appendix 2.

Comparison of incidence patterns

The incidences of 17 nonmetric traits are given in Table 4. When compared to the other modern Japanese, the incidence pattern of the northwestern Kyushu Japanese female was very similar to that of the northern Kyushu Japanese, and no significant difference existed in any of the traits. Although the incidence pattern of the northwestern Kyushu Japanese was similar to that of the Kanto–Tohoku Japanese, significant differences were seen in three traits. Compared with the Hokkaido Ainu, there were significant differences in five traits and the differences in these traits were marked. Although there were no significant differences in any trait compared with the northern Kyushu Yayoi, compared to the northwestern Kyushu Yayoi and Jomon, there were significant differences in five and seven traits, respectively. The degree of difference in traits that are considered important for ascertaining inter-group lineage relationships, such as supraorbital foramen, hypoglossal canal bridging, and transverse zygomatic suture vestige (Dodo, 1987; Dodo and Ishida, 1990; Kozintsev, 1990; Saiki et al., 2000), was particularly large.



Multivariate analyses

Smith’s MMDs were calculated among 12 samples based on the incidences of the 17 traits (Table 5). Northwestern Kyushu Japanese females were markedly close to the northern Kyushu Japanese and northern Kyushu Yayoi. They were also close to the Koreans, Hokuriku, and Kanto–Tohoku Japanese, and somewhat close to the Amami–Okinawa Islanders, Kinki Japanese, and Chinese. On the other hand, the northwestern Kyushu Japanese were markedly distant from the Hokkaido Ainu, northwestern Kyushu Yayoi and Jomon. A principal coordinate analysis using the MMDs was conducted to prepare a two-dimensional diagram (Figure 5). The 12 samples were divided into two major clusters: one cluster consists of the Jomon, northwestern Kyushu Yayoi, and Hokkaido Ainu on the positive side of axis I, the other cluster consists of the remaining nine samples placed on the negative side. In the latter cluster, the Chinese, Amami–Okinawa Islanders, and Kinki Japanese were slightly distant from the six samples comprising the northwestern Kyushu, northern Kyushu, Hokuriku and Kanto–Tohoku Japanese, Koreans, and northern Kyushu Yayoi. The northwestern Kyushu Japanese was located near the center.


View Details		Figure 5.
Two-dimensional display of the principal coordinate analysis based on the MMD matrix shown in Table 5. The cumulative proportion is 67.6%. Abbreviations are the same as those given in the footnote of Table 5.







Discussion

Regionality of modern female populations in the Japanese archipelago

The regionality and formation of modern people in the Japanese archipelago is well explained by the ‘dual structure model’ (K. Hanihara, 1991). According to this model, the modern Japanese are a mixture of two fundamentally distinct groups, an earlier group of the Jomon, and a later group of immigrants who appeared during the Yayoi period. Moreover, the Ainu and Ryukyuans are regarded as representing the relatively unmixed descendants of the Jomon. This model is supported by many morphological and genetic findings (T. Hanihara, 1991, 1992; Matsumura, 1995; Omoto, 1995; Omoto and Saito, 1997; Tokunaga et al., 2001), and also is consistent with the results of virological studies (Hinuma, 1985, 1986).

The regional features of modern females of the Japanese archipelago identified in this study may be summarized as follows: (1) the modern peoples of mainland Japan, including the northwestern Kyushu Japanese, are relatively close to the Koreans, Chinese, and northern Kyushu Yayoi according to the metrical and nonmetrical analyses (Figure 3, Figure 4, Figure 5); (2) the Hokkaido Ainu and Ryukyuans are comparatively close and form one cluster in the metrical analyses but are unlike the mainland Japanese (Figure 3, Figure 4), while the Ryukyuans are distant from the Hokkaido Ainu and close to the mainland Japanese according to the nonmetrical analysis (Figure 5). These findings are in agreement with the dual structure model in the metrical analyses, but somewhat in disagreement in the nonmetrical analysis. In recent years, many studies have found that the Ryukyuans share more morphological similarities with modern mainland Japanese than with the Ainu (Dodo et al., 1998, 2000; Manabe et al., 1999; Pietrusewsky, 1999; Dodo, 2001; Higa et al., 2003). The nonmetrical findings of this study support these reports.

Morphological characteristics of female crania in the northwestern Kyushu Japanese

As briefly mentioned in the introduction, modern male crania (n = 143) of the northwestern Kyushu Japanese are metrically characterized by a lower cranial vault, lower face, and lower orbit compared with those of the other modern Japanese and Koreans (Figure 6, reproduced from Noda, 1993). Moreover these characteristics are generally similar to the condition seen in the Jomon and northwestern Kyushu Yayoi series. For this reason, Noda (1993) suggested that the modern male Japanese of the northwestern Kyushu area was genetically influenced by the northwestern Kyushu Yayoi. We calculated Penrose’s shape distances of the modern samples compared by Noda (1993) to the northern Kyushu Yayoi, northwestern Kyushu Yayoi, and Tsukumo Jomon series. The findings shown in Table 6 indicate that the males of the northwestern Kyushu Japanese (as well as the other modern Japanese) were closer to the northern Kyushu Yayoi than to the northwestern Kyushu Yayoi or Tsukumo Jomon, but that among the six modern samples compared, they were the closest to the northwestern Kyushu Yayoi and Tsukumo Jomon.


View Details		Figure 6.
Mollison’s deviation curves of the male cranial measurements and indices, using the northwestern Kyushu Japanese as the baseline of comparison (reproduced from Noda, 1993). Length–height index (17:1), breadth–height index (17:8), upper facial height (48), upper facial indices (48:45, 48:46), and orbital index (52:51) of the five cranial series are all situated in the positive side of the baseline. In other words, the male of the northwestern Kyushu Japanese has a lower cranial vault, face, and orbit compared to the five populations.






The following conclusion may be drawn from the metrical analyses of female crania of the northwestern Kyushu Japanese: (1) the height of the neurocranium is relatively great in relation to length and breadth; and (2) facial breadth is relatively narrow and facial height is relatively great (Table 2, Figure 2). These characteristics were particularly marked in the northwestern Kyushu Japanese, but are also common in modern Japanese. The results of principal component analysis in Figure 3 show these findings clearly. With the first principal component, high scores represent broader and lower cranial vault and facial skeleton, while low scores represent narrower and higher vault and face. As a result, all modern Japanese are on the negative side, and the northwestern Kyushu Japanese have the lowest score. In contrast, the Tsukumo Jomon and northwestern Kyushu Yayoi, with a lower neurocranium and a lower, wider face, have the highest scores.

The craniometric characteristics of the northwestern Kyushu Japanese differ to some extent between males and females. Consequently, we consider that it is necessary to examine not only males but also females when discussing and understanding regionality of the modern Japanese population.

The following may be concluded from the nonmetrical analyses: (1) the incidence pattern seen in the northwestern Kyushu female Japanese is quite similar to that of the other modern Japanese; (2) compared to the Hokkaido Ainu, northwestern Kyushu Yayoi, and Jomon, incidences of the supraorbital foramen, hypoglossal canal bridging, and transverse zygomatic suture vestige were particularly large (Table 4). Several reports have pointed out the usefulness of these traits in lineage classification of the various groups of the Japanese archipelago (Dodo, 1987; Dodo and Ishida, 1990; Kozintsev, 1990; Saiki et al., 2000). Also, the relationships among the modern Japanese, Ainu, Yayoi, and Jomon people seen in the nonmetrical analyses of this study were in general agreement with results of previous nonmetrical studies (Dodo and Ishida, 1990, 1992; Kozintsev, 1990; Dodo et al., 1992; Saiki et al., 2000).

Relation between modern and Yayoi people in the northwestern Kyushu area

There were no marked similarities in female cranial characteristics between the modern and Yayoi people of the northwestern Kyushu area. Rather, the differences between both peoples were clarified. On the other hand, the northwestern Kyushu Japanese were metrically similar to the northern Kyushu Yayoi of continental lineage in terms of a high face, and Penrose’s shape distance between the two groups was relatively small. The incidence patterns of nonmetric cranial traits in both groups were also similar. These findings suggest that the northwestern Kyushu Japanese are not the direct descendants of the northwestern Kyushu Yayoi, and are genetically closer to the northern Kyushu Yayoi. Dodo and Ishida (1992) investigated the incidence of nonmetric cranial traits at specific periods spanning the Jomon to the modern, and stated, “The northern Kyushu Yayoi of continental lineage must be one of the forerunners of the modern Japanese of the central islands of Japan.” Saiki et al. (2000) offered the same conclusion. The results of this study also support the opinions of Dodo and Ishida (1992).

In the northwestern Kyushu area, hardly any human skeletal remains have been excavated from the protohistoric Kofun period (ca. 300 AD to 700 AD) to recent. It is therefore difficult to ascertain temporally based morphological changes of the skeleton. According to the results of metrical and nonmetrical analyses of the female crania, it can at least be suggested that people in the northwestern Kyushu area inherited the characteristics of the Jomon people up to the Yayoi period, and subsequently—during and after the Kofun period—were influenced by people migrating from the continent or their descendants. The resulting changes produced the characteristics seen in the modern Japanese people.


Acknowledgments

The authors wish to express our sincere thanks to Professor Seiji Nagashima, Graduate School of Biomedical Sciences, Nagasaki University for his guidance. We also wish to thank Professor Yukio Dodo, Graduate School of Medicine, Tohoku University for providing us with the raw data of the nonmetric traits of the modern Japanese in northern Kyushu area, Professor Takahiro Nakahashi, Graduate School of Social Science and Cultural Studies, Kyushu University, with unpublished measurements of the same modern Japanese, and Professor Hajime Ishida, Faculty of Medicine, University of the Ryukyus for observational advice on the nonmetric cranial traits.

References
Baba H. (1991) Osteometry. In: Eto M. (ed.), Jinruigaku-koza, Additional Volume 1: Anthropometry, II Osteometry. Yuzankaku Shuppan, Tokyo (in Japanese).
Bräuer G. (1988) Osteometrie. In: Martin R. and Knußmann K. (eds.), Anthropologie, Handbuch der vergleichenden Biologie des Menschen, Band 1. Gustav Fischer, Stuttgart, pp. 160–232.
Constandse-Westermann T.S. (1972) Coefficients of Biological Distance: An Introduction to the Various Methods of Assessment of Biological Distances between Populations, with Special Reference to Human Biological Problems. Anthropological Publications, Oosterhout, The Netherlands, pp. 1–142.
Dodo Y. (1974) Non-metrical traits in the Hokkaido Ainu and the northern Japanese of recent times. Journal of the Anthropological Society of Nippon, 82: 31–51.
Dodo Y. (1975) Non-metric traits in the Japanese crania of the Edo period. Bulletin of the National Science Museum, Series D, 1: 41–54.
Dodo Y. (1986) Observation on the bony bridging of the jugular foramen in man. Journal of Anatomy, 144: 153–165.
Dodo Y. (1987) Supraorbital foramen and hypoglossal canal bridging: the two most suggestive nonmetric cranial traits in discriminating major racial groupings of man. Journal of the Anthropological Society of Nippon, 95: 19–35.
Dodo Y. (2001) Different measurement methods of upper facial height strongly influence the results of craniometric analyses: metric study of the Ainu and Ryukyuan crania. Anthropological Science (Japanese Series), 108: 133–141 (in Japanese).
Dodo Y. and Ishida H. (1987) Incidences of nonmetric cranial variants in several population samples from East Asia and North America. Journal of the Anthropological Society Nippon, 95: 161–177.
Dodo Y. and Ishida H. (1988) Nonmetric analyses of the Doigahama crania of the Aeneolithic Yayoi period in western Japan. In: Yokoyama K. (ed.), Establishment of Japanese Peoples and Cultures. Rokko shuppan, Tokyo, pp. 127–142 (in Japanese).
Dodo Y. and Ishida H. (1990) Population history of Japan as viewed from cranial nonmetric variation. Journal of the Anthropological Society of Nippon, 98: 269–287.
Dodo Y. and Ishida H. (1992) Consistency of nonmetric cranial trait expression during the last 2,000 years in the habitants of the central islands of Japan. Journal of the Anthropological Society of Nippon, 100: 417–423.
Dodo Y., Ishida H., and Saitou N. (1992) Population history of Japan: a cranial nonmetric approach. In: Akazawa T., Aoki K., and Kimura T. (eds.), The Evolution and Dispersal of Modern Humans in Asia. Hokusen-sha, Tokyo, pp. 479–492.
Dodo Y., Doi N., and Kondo O. (1998) Ainu and Ryukyuan cranial nonmetric variation: evidence which disputes the Ainu-Ryukyu common origin theory. Anthropological Science, 106: 99–120.
Dodo Y., Doi N., and Kondo O. (2000) Flatness of facial skeletons of Ryukyuans. Anthropological Science, 108: 183–198.
Dodo Y., Doi N., and Kondo O. (2001) Metric data of Ryukyuan crania. Anthropological Science, 109: 183–190.
Esumi, Inc. (2002) Excel Multivariate Analysis Version 4.0. Tokyo.
Hanihara K. (1984) Geographical variations in the Japanese crania. In: The Anthropological Society of Nippon (ed.), Jinruigaku. Nikkei Science, Tokyo, pp. 78–87 (in Japanese).
Hanihara K. (1991) Dual structure model for the population history of the Japanese. Japan Review, 2: 1–33.
Hanihara K. (1993) Establishment of the modern Japanese. In: Baba H. (ed.), Anthropology: Where are the Modern Humans from?. Nikkei Science, Tokyo, pp. 146–157 (in Japanese).
Hanihara T. (1989) Comparative studies of geographically isolated populations on Japan based on dental measurements. Journal of the Anthropological Society of Nippon, 97: 95–107.
Hanihara T. (1991) Dentition of Nansei Islanders and peopling of the Japanese Archipelago: the basic populations in East Asia, IX. Journal of the Anthropological Society of Nippon, 99: 399–409.
Hanihara T. (1992) Dental and cranial evidence on the affinities of the East Asian and Pacific populations. In: Hanihara K. (ed.), Japanese as a Member of the Asian and Pacific Populations, International Symposium 4, 1992. International Research Center for Japanese Studies, Kyoto, pp. 119–137.
Hasebe K. (1917) The geographical difference in the modern Japanese crania. The Journal of the Anthropological Society of Tokyo, 32: 285–296 (in Japanese).
Higa T., Hanihara T., Sunakawa H., and Ishida H. (2003) Dental variation of Ryukyu islanders: a comparative study among Ryukyu, Ainu, and other Asian population. American Journal of Human Biology, 15: 127–143.
Hinuma Y. (1985) Natural history of the retrovirus associated with a human retrovirus. BioEssays, 3: 353–365.
Hinuma Y. (1986) The Tales of Viruses: Searching for the Origin of the Japanese through Virus Studies. Chuoukouron-sha, Tokyo.
Horai S., Hayasaka K., Murayama K., Wate N., Koike H., and Nakai N. (1989) DNA amplification from ancient human skeletal remains and sequence analysis. Proceedings of the Japan Academy, series B, 65: 229–233.
Horai S., Kondo R., Murayama K., Hayashi S., Koike H., and Nakai N. (1991) Phylogenetic affiliation of ancient and contemporary humans inferred from mitochondrial DNA. Philosophical Transactions of the Royal Society of London, series B, 333: 409–417.
Ikeda J. (1974) Craniometry of Miyako islanders, the Ryukyus. Journal of the Anthropological Society of Nippon, 82: 150–160 (in Japanese).
Ikeda J. (1998) The Roots of the Japanese. Asahishinbun-sha, Tokyo (in Japanese).
Kanaseki T. (1956) The question of the Yayoi people. In: Sugihara S. (ed.), Nippon Koukogaku Koza, Volume 4: Yayoi Culture. Kawade shobou, Tokyo, pp. 238–252 (in Japanese).
Kanaseki T. (1959) The physical characteristic of Japanese in the Yayoi-period. Proceedings of 15th General Assembly, Japan Medical Congress 1, pp. 167–174 (in Japanese).
Kanaseki T. (1966) The Yayoi people. In: Wajima S. (ed.), Nippon no Kokogaku, Volume 3: Yayoi Period. Kawade shobou, Tokyo, pp. 460–471 (in Japanese).
Kiyono K. and Miyamoto H. (1926) Anthropological studies on human bones from the shell-mounds of Tsukumo, Bitchu, part II: Crania. The Journal of the Anthropological Society of Tokyo, 41: 95–140, 150–208 (in Japanese).
Koganei Y. (1893) Beiträge zur physischen Anthropologie der Aino: I. Untersuchungen am Skelet. Mittheilungen aus der Medicinischen Facultät der Kaiserlich-Japanischen Universität, Band 2, Kaiserlichen Universität, Tokyo, pp. 1–249.
Kozintsev A. (1990) Ainu, Japanese, their ancestors and neighbors: cranioscopic data. Journal of the Anthropological Society of Nippon, 98: 247–267.
Kurosaki K., Matsushita T., and Ueda S. (1993) Individual DNA identification from Ancient human remains. American Journal of Human Genetics, 53: 638–643.
Manabe Y., Kitagawa Y., Oyamada J., Kato K., Ito R., Kobayashi S., and Rokutanda A. (1999) Genealogical positioning of the Okinawa main islanders in East Asia populations based on nonmetric tooth crown traits. Anthropological Science, 107: 85.
Matsumoto S. (1956) Anthropological study on the skulls of the modern Japanese in central Kyushu (Higo). Journal of Kumamoto Medical Society, 30: 834–879 (in Japanese).
Matsumura H. (1995) A microevolutional history of the Japanese people as viewed from dental morphology. National Science Museum Monographs, No. 9, National Science Museum, Tokyo, pp. 1–130.
Miyamoto H. (1924) Anthropologische Untersuchungen über das Skelett der rezenten Japaner: I. Der Shädel. The Journal of the Anthropological Society of Tokyo, 39: 307–451(in Japanese).
Morita S. (1950) Anthropological study of the Kanto Japanese skulls. Report of Department Anatomy, Jikei University School of Medicine, 3: 1–59 (in Japanese).
Mouri T. (1976) A study of non-metrical cranial variants of the modern Japanese in the Kinki District. Journal of the Anthropological Society of Nippon, 84: 191–203.
Mouri T. (1986) Geographical and temporal variation in Japanese populations as viewed from nonmetric traits of the skull. Ph.D dissertation, Kyoto University, pp. 1–79 (in Japanese).
Mouri T. (1988) Incidences of cranial nonmetric characters in five Jomon populations from West Japan. Journal of the Anthropological Society of Nippon, 96: 319–337.
Naito Y. (1971) On the human skeletons of Yayoi period excavated at the sites in north-western Kyushu. Journal of the Anthropological Society of Nippon, 79: 236–248 (in Japanese).
Naito Y. (1981) Human skeletal remains of the Yayoi period. In: Ogata T. (ed.), Jinruigaku-koza, Volume 5: The Japanese I. Yuzankaku shuppan, Tokyo, pp. 57–99 (in Japanese).
Naito Y. (1984) The transition from the Jomon to the Yayoi skeletons in Kyushu. In: The Anthropological Society of Nippon (ed.), Jinruigaku. Nikkei-Science, Tokyo, pp. 52–59 (in Japanese).
Nakahashi T. (1993) Temporal craniometric changes from the Jomon to the modern period in western Japan. American Journal of Physical Anthropology, 90: 409–425.
Nakahashi T. and Nagai M. (1989) The physical features of the Yayoi people. In: Nagai M., Nasu T., Kanaseki H., and Sahara M. (eds.), The Studies of the Yayoi Culture, Volume 1. Yuzankaku shuppan, Tokyo, pp. 23–51 (in Japanese).
Nakahashi T., Doi N., and Nagai M. (1985) Human skeletal remains of the Yayoi period excavated from the Kanenokuma site. In: Shiseki Kanenokuma Iseki. Educational Committee of Fukuoka City, Fukuoka, pp. 43–145 (in Japanese).
Noda K. (1993) Anthropological study of modern male skulls in the northwestern Kyushu district. Nagasaki Igakukai Zasshi, 68: 179–194 (in Japanese).
Omoto K. (1995) Genetic diversity and the origins of the ‘Mongoloids’. In: Brenner S. and Hanihara K. (eds.), The Origin and Past of Modern Human as Viewed from DNA. World Scientific, Singapore, pp. 92–109.
Omoto K. and Saito N. (1997) Genetic origins of the Japanese: a partial support for the dual structure hypothesis. American Journal of Physical Anthropology, 102: 437–446.
Oota H., Saito N., Matsushita T., and Ueda S. (1995) A genetic study of 2,000-year-old human remains from Japan using mitchondrial DNA sequences. American Journal of Physical Anthropology, 98: 133–145.
Ossenberg N.S. (1986) Isolate conservatism and hybridization in the population history of Japan: the evidence of nonmetric cranial traits. In: Akazawa T. and Aikens C.M. (eds.), Prehistoric Hunter-Gatherers in Japan. The University Museum, The University of Tokyo, Bulletin, No. 27, pp. 199–215.
Otsuki Y. (1930) Anthropological studies on the Japanese skulls from Hokuriku district. Journal of Juzen Medical Society, 35: 81–97, 606–621, 1980–1998, 2575–2590 (in Japanese).
Pietrusewsky M. (1999) A multivariate craniometric study of the inhabitants of the Ryukyu Islands and comparisons with cranial series from Japan, Asia, and the Pacific. Anthropological Science, 107: 255–281.
Saiki K., Wakebe T., and Nagashima S. (2000) Cranial nonmetrical analyses of the Yayoi people in the northwestern Kyushu area. Anthropological Science, 108: 27–44.
Shima G. (1933) Anthropological study of the Chinese skull obtained from the suburbs of Fushun, Manchuria. The Journal of the Anthropological Society of Tokyo, 48: 423–537 (in Japanese).
Shima G. (1934) Further notes on the anthropological studies of the modern Koreans (the skull). The Journal of the Anthropological Society of Tokyo, 49: 245–267 (in Japanese).
Shinoda K. and Kanai S. (1999) Intracemetery genetic analysis at the Nakazuma Jomon site in Japan by mitochondrial DNA sequencing. Anthropological Science, 107: 129–140.
Shinoda K. and Kunisada T. (1990) Extraction and amplification of the human mitochondrial DNA from the Jomon skeletal remains. Journal of the Anthropological Society of Nippon, 98: 471–482 (in Japanese).
Shinoda K. and Kunisada T. (1994) Analysis of ancient Japanese society through mitochondrial DNA sequencing. International Journal of Osteoarchaeology, 4: 291–297.
Sjøvold T. (1973) The occurrence of minor nonmetrical variants in the skeleton and their quantitative treatment for population comparisons. Homo, 24: 204–233.
Takenaka M. (1994) Morphological traits of crania in modern Kyongsangnam-do Koreans. Acta Anatomica Nipponica, 69: 645–660.
Tanaka Y., Tarumi T., and Wakimoto K. (1984) Handbook for Statistical Analysis by Personal Computer, Volume 2: Multivariate Analysis. Kyoritsu shuppan, Tokyo (in Japanese).
Tokunaga K., Ohashi J., Bannai M., and Juji T. (2001) Genetic link between Asians and native Americans: evidence from HLA genes and haplotypes. Human Immunology, 62: 1001–1008.
Wang L. and Sun F. (1988) A study on the skulls from Taiyuan, Shanxi. Acta Anthropologia Sinica, 7: 206–214 (in Chinese).
Yamaguchi B. (1973) Facial flatness measurements of the Ainu and Japanese crania. Bulletin of the National Science Museum, 16: 161–171.
Yamaguchi B. (1978) The Japanese skeletons. In: Ikeda J. (ed.), Jinruigaku-koza Volume 6: The Japanese II. Yuzankaku shuppan, Tokyo, pp. 143–174 (in Japanese).
Yamaguchi B. (1990) The Ancestors of Japanese. Tokuma shoten, Tokyo (in Japanese).
Yamasaki M., Yamasaki M., Kanda S., and Kurisu K. (1967) Craniometrical study of the Tohoku Japanese skulls. The Journal of the Anthropological Society of Nippon, 75: 94–99 (in Japanese).