To examine population affinities in light of the ‘dual structure model’, frequencies of 21 nonmetric cranial traits were analyzed in 17 prehistoric to recent samples from Japan and five from continental northeast Asia. Eight bivariate plots, each representing a different bone or region of the skull, as well as cluster analysis of 21-trait mean measures of divergence using multidimensional scaling and additive tree techniques, revealed good discrimination between the Jomon-Ainu indigenous lineage and that of the immigrants who arrived from continental Asia after 300 BC. In Hokkaido, in agreement with historical records, Ainu villages of Hidaka province were least, and those close to the Japan Sea coast were most, hybridized with Wajin. In the central islands, clines were identified among Wajin skeletal samples whereby those from Kyushu most resembled continental northeast Asians, while those from the northernmost prefectures of Tohoku apparently retained the strongest indigenous heritage. In the more southerly prefectures of Tohoku, stronger traces of Jomon ancestry prevailed in the cohort born during the latest Edo period than in the one born after 1870. Thus, it seems that increased inter-regional mobility and gene flow following the Meiji Restoration initiated the most recent episode in the long process of demic diffusion that has helped to shape craniofacial change in Japan.
The aim of this study is to clarify the odontometric features of the people in the medieval period in Japan. We investigated the human skeletal remains of the Yuigahama-minami, Chusei Shudan Bochi, Seiyokan, and Gokurakuji sites; this is the first study to address the odontometry of multiple medieval skeletal populations of Kamakura city. Dental crown measurements were statistically compared with those of the other population samples dating from prehistoric to modern times. The results of our multivariate odontometric study allow some tentative perspectives regarding the relationship between the medieval and other prehistoric and historic Japanese series. First, the medieval series were found to have an odontometric pattern close to the Yayoi, Kofun, Edo, and modern series, and well differentiated from that of the Jomon and Ainu series. Second, the majority of the medieval series tended to have smaller tooth size than the post-Jomon series of the Yayoi, Kofun, Edo, and modern periods. We suggest that the small tooth size of the Kamakura medieval series may be related to non-lineage factors, and would not contradict their similarity in odontometric pattern with the Yayoi, Kofun, Edo, and modern series.
Somatometric research was conducted in Tonga, Polynesia, with a focus on foot and hand size and proportions. Data were taken on 140 adults (90 females and 50 males) and compared with those of other population groups. In addition to their heavy body-build, Tongans were found to have significantly longer and wider feet and hands than the Japanese, French, Australian Aborigines, or Bamanann-Fulbe West Africans. The significance of these physical characteristics of Polynesians is discussed from a micro-evolutionary viewpoint.
Although JC polyomavirus (JCPyV) genotyping is a promising method in clarifying the peopling of the Pacific, the distribution of JCPyV lineages has been elucidated only in a few Pacific populations. To clarify JCPyV lineages of the Kiribati Islanders, we collected urine samples from 48 Kiribati fishermen (mainly from the Gilbert Islands), who called in at a Japanese port for unloading. From the urine samples, we amplified the 610-bp IG region (VT-intergenic region) of the viral genome using the polymerase chain reaction. We obtained and sequenced IG fragments from 35 samples. From the resultant sequences, together with reference IG sequences, a neighbor-joining phylogenetic tree was constructed to classify the JCPyV isolates into lineages. We detected 2E (one of the major Pacific lineages) in 27 samples (77%), SC (the major Southeast Asian lineage) in seven samples (20%), and EU-a (one of the major European lineages) in one sample (3%) (the rare EU-a isolate was probably recently introduced to Kiribati by Europeans). A phylogenetic analysis based on complete viral DNA sequences revealed that the SC isolates in Kiribati belonged to a new sublineage (named SC-g) within the SC lineage. The present findings agree with the view that the 2E lineage of JCPyV accompanied the Austronesian dispersals in the Pacific. In addition, our findings suggest that ancient Southeast Asians, carrying SC-g, also migrated to the central Pacific islands.
Nonmetric cranial variation of the Ryukyuans, including the Kumejima population, and their neighboring peoples was investigated. Among the populations compared, incidences of supernumerary ossicles in the Ryukyu series were high. The frequency of the supraorbital foramen of the Kumejima series was shown to be intermediate between those of the East Asians and Ainu. Mean measures of divergence (MMDs) based on 16 nonmetric traits showed that Kumejima is closest to Okinawa, Sakishima, and Amami, as well as to the Philippine and Yayoi groups. The four Ryukyu groups were the most distant from the Hawaii population. Multidimensional scaling and neighbor-joining methods were applied to the distance matrix to represent the relationships among populations. The four Ryukyu groups grouped together with the Yayoi to form a cluster, which was positioned between the East and Southeast Asians and the Jomon-Ainu populations. This suggests that there were not only northern, but also southern influences on the Ryukyu Islands during prehistoric and historic times, as suggested by recent genetic studies.
Atlas bridging represents the formation of a bony bridge over the vertebral artery groove of the first cervical vertebra. There are two kinds of bridging, the ‘posterior bridge’ and the ‘lateral bridge’. Such bridges may occur together or separately, and bilaterally or unilaterally. We investigated ontogenetic change and geographical variation of atlas bridging in Japanese macaques (Macaca fuscata) to clarify age effects and frequencies within a species. A total of 193 skeletal specimens of Japanese macaques of known chronological age were examined for ontogenetic change. Atlas bridges, both posterior and lateral, were present in most adults; they were found to develop at an early age. The posterior and lateral bridges were found complete at around 400–830 and 700–2500 days, respectively, after birth. A total of 328 Japanese macaques (Macaca fuscata fuscata and Macaca fuscata yakui) from seven regions were used in the study of geographical variation. Both posterior and lateral bridges were commonly observed regardless of region, with a tendency for a slightly lower prevalence of the lateral bridge than the posterior bridge. Atlas bridging did not differ in frequency between the right and left sides. Sexual differences were not significant in most of the populations. As for the lateral bridge, the Shimane population had a lower frequency than that found in the other populations. However, even considering such intraspecific variation, atlas bridging can be considered as a stable trait within Japanese macaques, the prevalence of which is remarkably higher than in hominoids.
Genetic adaptation to malaria is a longstanding research topic in anthropology and human genetics. Southeast Asian ovalocytosis (SAO) has been documented to have resistance to malaria; however, the implications of existing data are controversial. In particular, SAO resistance to malaria is unlcear in terms of the types of SAO, with/without the 27-base pair deletion in the band 3 gene (B3Δ27). To shed light on the relationships between SAO and malaria, we surveyed Plasmodium infection, erythrocyte morphology, and the presence of the B3Δ27 among the residents of a selected area in East Kalimantan, Indonesia where malaria is endemic. We screened peripheral blood smears (n = 128) for Plasmodium infection and erythrocyte morphology under a microscope, and then DNA was extracted from the smears to be used as a template for a polymerase chain reaction to detect the B3Δ27. The prevalence of infection with Plasmodium including Plasmodium vivax and Plasmodium falciparum was approximately 30%. Among a total of 128 subjects, 9.4% and 18.0% showed moderate (ovalocytic cells: 30–49%) and severe (ovalocytic cells: 50–100%) ovalocytosis, respectively. A total of three B3Δ27 carriers were identified. The data set was statistically analyzed and we observed that (1) higher ovalocytic rate resulted in lower malaria infection and (2) the B3Δ27 did not prevent malaria infection. These results suggest that resistance of SAO to malaria is due to SAO without the B3Δ27.
Following the economic development policy of China since the 1980s, the indigenous food production systems of communities have been transformed to a market economy. The introduction of cash crops has been the major developmental policy of China’s rural areas. Despite the overall improvement of economic status among farmers over the last two decades, inequality among households has emerged as a new problem. In the present study, we investigated the process of how cash crops were accepted in a Li hamlet in Hainan island, China, and how this has influenced the labor and dietary patterns of people. In examining this process, we focussed on inter-household differences. We also reconstructed the demographic changes and land use patterns of all the households of the hamlet for the period between 1985 and 2004. Data on labor and diet of 11 representative households were collected by direct measurement/observation from a total of 12 months of fieldwork in 2000–2004. Reconstruction of the adoption process revealed two important factors that might contribute to current variation among households: (1) the success of pioneering households, which played an important role in triggering the hamlet-level adoption of cash crops, and (2) the availability of labor resources during 1995–2004, which explains the inter-household variation observed in 2004. The households that succeeded in cash cropping appeared to be able to afford further investment in cash cropping, which may have further enlarged inter-household variation. Inter-household variation in cash cropping in 2004 partly explains inter-household variation in food consumption and labor hours. The intensification and maintenance of rice cultivation may alleviate the nutritional (initial phase) and work burden posed by the adoption of cash cropping.