Since the discovery of Gm st gene which characterizes Mongoloid populations in 1966, the distribution of the genetic markers of immunoglobulins (Gm haplotypes) among the Mongoloid and neighboring populations scattered from Southeast Asia through East Asia to South America has been investigated and concluded as follows:
1) Mongoloid populations are divided into two groups on the basis of analysis of genetic distances based on the Gm haplotype frequencies: One is a southern group characterized by a remarkably high frequency of Gm afb1b3 and a low frequency of Gm ag and the other is a northern group characterized by a high frequency of Gm ag and an extremely low frequency of Gm afb1b3.
2) Populations in China, mainly Han including minority nationalities, show remarkable heterogeneities from north to south, in sharp contrast to Korean and Japanese populations showing homogeneities, respectively. The center of dispersion of the Gm afblb3 characterizing southern Mongoloids must exist in Guangxi and Yunnan area in the southwest China.
3) The Gm ab3st gene found in the highest incidence among the north Baikal Briats flows in all directions. The gene, however, shows precipitous drop which occur from mainland China to Southeast Asia and from North to South America, although the Gm ab3st gene is still found in high incidences among Eskimos, Yakuts, Tibetans, Oroqens, Koreans, Japanese and Ainu. On the other hand, the gene is introduced into Hui, Uygur, Indians, Iranians and far into Saldinians in Italy. On the basis of these results, it should be concluded that Japanese race belongs to northern Mongoloids and that the origin of Japanese race must exist in Siberia, most likely in the Baikal area.

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During an investigation into dentofacial morphology and dental diseases in skeletal remains of the recent Ainu, several traits of tooth loss, probably due to ritual tooth ablation, were observed. Since KANESEKI (1940) predicted the existence of this ritual in Ainu, there was no study concerned with this problem in Ainu. In the present paper, it was aimed to announce that this ritual really existed in Ainu.
Materials used in this investigation were 125 skulls of the recent Ainu, which were preserved in the University Museum, The University of Tokyo (Table 1). Traits of tooth ablation were observed in 19 cases, and the total number of extracted teeth was 45. Most of the teeth extracted were central and lateral incisors in both maxilla and mandible, and the ablation of the maxillary canines was observed in only two cases (Table 2 and Fig. 1). The frequency of the cases with ritual tooth extraction was 15.2% as a whole, and the highest incidence of 20.6% was observed in the Okhotsk coast area, except Sakhalin in which only one sample was obtained and it was the case of ritual ablation (Table 3 and Fig. 2).
There were three cases out of thirty juveniles, 10.0%; 11 cases of 76 adults, 14.5%; two cases of ten matured people, 20.0%; and three cases of nine seniles, 33.3%. These facts may suggest that the extraction was not carried out at some decided ages such as adolescence, but it was done in more than one, or several occasions even after adulthood. There were 11 extracted cases out of 66 males, 16.7%; and six cases of 46 females, 13.0%; two cases of 13 unknown cases, 15.4% (Table 4).
The differential diagnosis of ritual tooth ablation from the traits of tooth loss for other reasons contained very few difficulties. However, it seemed impossible to discriminate the ritual ablation from tooth loss due to accidental trauma. It was also difficult to confirm the ritual ablation in the case in which most of the teeth had been lost for old age (Fig. 3). In these points, the authors agree with HRDLICKA (1940) as well as with OHTAWA (1983), particularly concerning the shape of alveolar bone in the ablation cases that becomes kniferidge like, and the HRDLICKA'S expression, Such a diagnosis, with sufficient experience, is fortunately not overdifficult, seems really acceptable. Naturally, a question arose to the contrary opinion of MERBS (1968) that all the HRDLICKA'S 1165 cases out of 6645 samples from Siberia and America must be caused by unintentional trauma occasioned by use of the anterior dentition as a tool.
Space closure after ritual tooth ablation was not dominant, but only slightly observed. Since KOGANEI (1919) pointed out that the extraction space closed itself with time, many authors made efforts to estimate the time of ablation, and the order of tooth extraction when more than one teeth were lost, and to find the real reason of this strange ritual. These discussions, however, do not seem to be fruitful, because the amount and the rate of space closure do not simply relate to the time factor, but they change depending on the extent of the toothto-denture-base discrepancy in each individual, or even in each jaw (INOUE, 1980; INOUE et al., 1983; Fig. 4). For this reason, there is a limitation in estimating the elapsed time after the tooth extraction only from the size of the remaining space.
The type of ablation, in which the central and lateral incisors in both maxilla and mandible are extracted, is very close to those of the Siberians and the American natives (HRDLICKA), and differed from those in the Jomon people in Hokkaido (DoDo et al., 1984), and also from Japanese skeletal remains from the Jomon and Yayoi periods (Table 5). From these facts, it is presumed that there has been strong influences of the so-called Northern Cultures on the Ainu, since they had been isolated from the Japanese in Honshu, both culturally and physically, probably after the Jomon period.

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Geographic variations in metrical characteristics of Kofun skulls were examined, using the principal component analysis. The genetic influence of immigrants in northern Kyushu appeared as a geographical cline in the cranial measurements obtained by the method of MARTIN and SALLER (1957). We considered that the cline originated from the migration and gene mixture, since the Yayoi period. The following three clinal forms were determined from the relationship between the distance and the score of the first principal component in each series: 1) abrupt fall-off curve, 2) gentle fall-off curve, and 3) linear or irregular type. These three types seemed to show different rates of gene flow. The direction of diffusion to the east may represent local migration to obtain favorable land for cultivation.

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This study was made to establish criteria of leanness in schoolboys and girls by means of allometry ; leanness was defined as lower lean body mass to height. Anthropometric measurements were taken on approximately 8, 700 children ages 6 to 17 years from elementary school, junior and senior high school in northern Kyushu. Percent body fat and lean body mass were estimated from height, body weight and skinfold thicknesses. Allometric equations of lean body mass (LBM) on height (Ht) were calculated for all age groups of both sexes, that is, LBM=2.47×10-5×Ht^2.83 for boys and LBM=2.43×10^-5×Ht^2.82 for girls, respectively. There was a statistically significant sex difference between the two equations, although the relative growth coefficients were apparently similar to each other. Criteria of leanness were determined by the lines at intervals of two standard errors of estimate (2SEE) below the allometric equations, and the subject whose lean body mass was plotted below this line was regarded as lean. Based on the criteria obtained here, subjects combining both leanness and fatness were found.

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Principal components analyses of subcutaneous fat measurements covering triceps, subscapular, iliac, abdominal and thigh of the body were performed on 103 male and 100 female Japanese young adults. Three major components emerged, similar, in the both sexes from the intercorrelation matrix of the five or four skinfolds. Inspection of the component loadings reveals the first component to contain only positive loadings, whereas the remaining components contain both positive and negative loadings. The first component accounts for 83.5% and 53.8% of the total variance in the analysis of five sites for males and females, respectively. This component describes a fatness or size factor. The second and third components represent the pattern of fat distribution independent of size and fatness. The male second component contrasts the triceps and thigh skinfolds with the subscapular, iliac, and abdominal skinfolds. For the females, the second component contrasts the triceps and thigh with the iliac and abdominal skinfolds. Thus, the second component contrasts what may be called extremity-trunk fat patterning for both sexes and accounts for 8.7% and 19.6% of the total variance for males and females, respectively. The third component for the males contrasts the triceps and subscapular skinf olds with iliac and thigh skinfolds; for the females, the subscapular skinfold is contrasted with the iliac, abdominal and thigh skinfold. Thus, for both sexes the third component represents upper-lower body fat patterning contrast and accounts for 4.2% and 10.4% of the total variance for males and females, respectively.
The first and second components have been also reported in the previous studies which used the samples varying age, sex, ethnicity and adiposity. The cross-study consistency of these components suggests their applicability to the discription of the fat distribution pattern of Japanese young adults. The fat distribution pattern also contains the information as a risk factor for diabetes and coronary artery desease, thus contributing to the epidemiological aspect.

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Many skeletons of dogs of the Jomon period have been reported in Japan. There is little information, however, regarding medieval dogs. In 1953, the medieval burial site was excavated in Zaimokuza (Kamakura, Kanagawa Pref.). Human skeletons including 556 skulls with many of horses and dogs were unearthed there. These dogs are very important for tracing the phylogeny of the ancient Japanese dog.
We examined morphologically eight reconstructed dog skulls (six males and two females) and three other anomalous or injured skulls. The numbers of the dogs at this site was 30, as estimated by the number of lower first molars. Young dogs were rarely found at this site. Although skeletons were well preserved, many skulls were fragmented. One skull seems to have been cut by a sharp instrument such as a Japanese sword. Nearly one-third of human long bones have terminal bite injuries caused by dogs (KOHARA, 1956). They might have been killed by a sword or stick because they were eating human corpses.
The maximum cranial length of the Zaimokuza dogs (male: 170-180mm, female: 156-161mm) was longer than that of the Jomon dogs (Tagara dogs). According to the size categories described by HASEBE (1956), male dogs were of the medium type and female dogs were of the medium small type. The latter medieval dog (Kutsukake dog in the mid-sixteenth century) and early modern dogs (Asahinishi dogs and Sannomaru dogs in the seventeenth century) had similar size crania. The size of the Japanese dogs gradually became larger after Jomon period. A similar tendency was observed in North American ancient dogs by HAAG (1948). This tendency of cranial enlargement was considered to be mainly due to evolutionary changes in the Japanese dogs, and not by interbreeding with dogs imported from the other countries. The cranial enlargement continued until the Kamakura period.
The depression between the muzzle and the top of the frontal bone, the so-called stop, was slightly smaller than that of the Jomon dogs and was much smaller than that of the recent Shiba dogs. The cranial breadth and the cranial height were smaller than those of the Shiba dogs, but were similar to those in Jomon dogs. The foramen magnum showed a primitive oval form as observed in Jomon dogs. The Zaimokuza dog skeletons were very robust compared with the recent Shiba dogs. Individual variations in size and shape were greater than those in the Jomon dogs.
Many of the features of Zaimokuza dogs were similar to those in Jomon dogs, but were different from those of the late medieval and early modern dogs, especially the present Shiba dogs. In contrast to the size enlargement, the cranial proportion of the Japanese dogs was found to have changed mainly after the Kamakura period.

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A clearly defined, circular hollow, 50mm in diameter and 20mm in depth, was found in the skull of a mature female skeleton (Ojo-1) excavated from the disused burial ground (ca. 18th century) in Okuchi City, Kagoshima Prefecture. The hollow was situated toward the nasal root region around the glabella. The marginal area in the frontal bone was ridged and the orbital roof was thinned and depressed into the orbit on both sides of the skull. The bone surface of the hollow was smooth, and partial new bone formation was observed. No other pathological change was seen in this skeleton. From these observations, it is possible to speculate that the hollow may have been produced by a gradual compression due to the extension of a cyst or benign soft tissue tumor in the frontal sinus. Taking present-day cases into consideration, frontal mucocele seems to be the most likely origin for the hollow.

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The number of migrants to Japan during the period of 1, 000 years from the Aeneolithic Yayoi to early historic ages (ca. 300 B. C. to ca. 700 A. D.) were estimated by means of 2 models of simulation. One is the population growth model and the other the morphological change model. Both models provide almost the same estimates which suggest the number of the migrants might have been much greater than was expected. The total number of migrants from the Asian Continent is estimated to be more than a million by the 7th century and the proportion of the populations of native Jomon and migrant lineages was supposed to be roughly 1:9 or 2:8 in the protohistoric Kof un and early historic ages, at least in west Japan. Although the models applied in the present study are still immature, the results obtained seem to represent considerable significance for further analyses on the formation processes of the Japanese population.

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