Metric dental variation of major human populations

Mesiodistal and buccolingual crown diameters of all teeth recorded in 72 major human population groups and seven geographic groups were analyzed. The results obtained are fivefold. First, the largest teeth are found among Australians, followed by Melanesians, Micronesians, sub-Saharan Africans, and Native Americans. Philippine Negritos, Jomon/Ainu, and Western Eurasians have small teeth, while East/Southeast Asians and Polynesians are intermediate in overall tooth size. Second, in terms of odontometric shape factors, world extremes are Europeans, aboriginal New World populations, and to a lesser extent, Australians. Third, East/Southeast Asians share similar dental features with sub-Saharan Africans, and fall in the center of the phenetic space occupied by a wide array of samples. Fourth, the patterning of dental variation among major geographic populations is more or less consistent with those obtained from genetic and craniometric data. Fifth, once differences in population size between sub-Saharan Africa, Europe, South/West Asia, Australia, and Far East, and genetic drift are taken into consideration, the pattern of sub-Saharan African distinctiveness becomes more or less comparable to that based on genetic and craniometric data. As such, worldwide patterning of odontometric variation provides an additional avenue in the ongoing investigation of the origin(s) of anatomically modern humans.     

Dental morphology of the early Hoabinian, the Neolithic Da But and the Metal age Dong Son civilized peoples in Vietnam

The early Hoabinian, the Neolithic Da But and the Dong Son (early Metal age) civilized peoples in northern Vietnam were investigated based on dental morphology and were compared with specimens from surrounding Northeast and Southeast Asia including Australians and Melanesians. In both the metric and nonmetric tooth traits, the Hoabinian and Da But specimens had dental features similar to the prehistoric Southeast Asians and the Australo-Melanesians, but also had partially Northeast Asian characteristics. On the other hand, the Northeast Asian features become distinct in the dentition of the Dong Son people, which have close ties with the modern Vietnamese. Thus, the Vietnamese, as well as the other modern Southeast Asians and Japanese, are considered to be a blend of indigenous Southeast Asians who are closely related to the Australo-Melanesian lineage, and migrants from Northeast Asia.     

A morphometric analysis of the Late Pleistocene Human Skeleton from the Moh Khiew Cave in Thailand.

Few Late Pleistocene human remains have been found in Southeast Asia and the morphological features of the people of that age are still largely unknown due to the virtual lack of human remains in the area. Recent excavations at the Moh Khiew Cave in Thailand resulted in the discovery of a Late Pleistocene human skeleton in a relatively good state of preservation. An AMS radiocarbon date on the charcoal sample gathered from the burial gave a result of 25,800 +/- 600 BP, implying that the inhabitants of Moh Khiew Cave resided in a part of Sundaland during the last glacial age. In debates on the population history of Southeast Asia, it has been repeatedly advocated that Southeast Asia was occupied by indigenous people akin to present-day Australo-Melanesians prior to an expansion of migrants from Northeast Asia into this area. Morphometric analyses were undertaken to test the validity of this hypothesis. In the present study, cranial and dental measurements recorded from the Moh Khiew remains are compared with those of early and modern samples from Southeast Asia and Australia. These comparisons demonstrate that the Moh Khiew specimen resembles the Late Pleistocene series from Coobool Creek, Australia in both cranial and dental measurements. These results suggest that the Moh Khiew skeleton, as well as other fossil remains from the Tabon, Niah and Gua Gunung sites, represents a member of the Sundaland population during the Late Pleistocene, who may share common ancestry with the present-day Australian Aborigines and Melanesians.     

Dental and cranial affinities among populations of east Asia and the Pacific: the basic populations in east Asia, IV.

The origins of the four major geographical groups recognized as Australomelanesians, Micronesians, Polynesians, and East and Southeast Asians are still far from obvious. The earliest arrivals in Sahulland may have migrated from Sundaland about 40,000-50,000 years B.P. and begun the Australomelanesian lineage. The aboriginal populations in Southeast Asia may have originated in the tropical rain forest of Sundaland, and their direct descendants may be the modern Dayaks of Borneo and Negritos of Luzon. These populations, the so-called "Proto-Malays," are possible representatives of the lineage leading to not only modern Southeast Asians, but also the Neolithic Jomon populations in Japan. The present study suggests, moreover, that the Polynesians and western Micronesians have closer affinities with modern Southeast Asians than with Melanesians or Jomonese.     

Craniofacial affinities of Mariana Islanders and Circum-Pacific peoples

Metric craniofacial variation was studied in a number of skeletal samples that originated from the Mariana Islands and circum-Pacific regions. The broad comparisons including East/Southeast Asians, Polynesians, Melanesians, and Australians confirm the relationships between Mariana Islanders and East/Southeast Asians on the one hand and Polynesians on the other hand. A transformation of Melanesians into western Micronesians is not supported. The result of the principal component analysis indicates that the cranial morphological pattern of Mariana people shares the intermediate characteristics between those of typical East/Southeast Asians and several groups falling as outliers to more predominant Asian populations. Am J Phys Anthropol 104:411–425, 1997. © 1997 Wiley-Liss, Inc.     

Dental anthropological indications of agriculture among the Jomon people of central Japan. X. Peopling of the Pacific

The high rate of crown caries (8.6%; 119/1,377 teeth) and other oral pathologies in 101 central Japan Middle to Late Jomon Period (ca. 1000 B.C.) crania indicate a level of carbohydrate consumption consistent with an agriculture hypothesis. Because Jomon dental crown and root morphology shows strong resemblances with past and present Southeast Asians, but not with ancient Chinese or modern Japanese, Jomon agriculture could be of great antiquity in the isolated Japanese islands. These dental data and other assembled facts suggest that ancestral Jomonese might have carried to Japan a cariogenic cultigen such as taro before the end of the Pleistocene from tropical Sundaland by way of the now-submerged east Asian continental shelf.     

Polynesian dentition

The chance discovery of a paper by Rottstock et al. (1983) comparing the individual diameters of 4,497 teeth from 711 skulls from anthropologically-different populations (Europeans, Negroids, Mongoloids, Melanesians) provided the impetus to add our measurements of 449 teeth from 89 Polynesians (mainland Maoris, Chatham Island, Wairau Bar) to the series. We confirm that dental measurements provide clear differences among the different population groups. We confirm that dental indices are useful by disclosing specific dental relationships among the different population groups.     

Globin genes in Micronesia: origins and affinities of Pacific Island peoples.

DNA polymorphisms and copy-number variants of alpha-, zeta-, and gamma-globin genes have been studied in seven Micronesian island populations and have been compared with those in populations from Southeast Asia, Melanesia, and Polynesia. Micronesians are not significantly different from Polynesians at these loci and appear to be intermediate between Southeast Asians and Melanesians. There is evidence of significant Melanesian input into the Micronesian gene pool and of substantial proto-Polynesian contact with Melanesia.     

Additional features of Ainu dentition. V. Peopling of the pacific

Crown morphology of 85 plaster dental casts from skeletal and living Ainus of less than 1/8 non-Ainu admixture is described and compared for microevolutionary and origins considerations. There is no significant sex dimorphism and few inter-sample differences through time. Inter-observer differences occur where observation standards are poorly established. Ainu teeth exhibit a simplified pattern and have trait frequencies more like those of Polynesians and Micronesians than like Chinese, Japanese or Europeans. There is no dental evidence in support of a Caucasoid origin or close relationship. Similarities outnumber differences between Ainu teeth and those of Micronesians and Polynesians suggestive of a past biological relationship.     

广西化石猩猩牙尖釉质的日分泌率

作为现仅存于亚洲大陆的现生大猿,更新世时期猩猩曾广泛分布于东南亚大陆及华南地区,但其保留下来的化石材料主要为单颗牙齿。从牙齿形态、尺寸等外部特征的研究得出的关于猩猩的分类及演化问题的结论并未得到广泛一致的认同,而研究表明牙齿生长发育特征可作为系统分类研究的一个潜在工具。本研究选取了一批来自于中国广西更新世时期的猩猩牙齿化石,制作牙齿组织学切片,测量计算了其牙釉质日分泌率,结果显示广西化石猩猩牙尖釉质日分泌率在2.32-6.88μm/d之间,平均值约为4.61μm/d,从牙尖内部到表面,釉质日分泌率有增加趋势。此外,还将广西化石猩猩与其他现生大猿和现代人进行比较,以期从牙齿生长发育的角度为猩猩的演化和分类问题提供一点线索和证据。     

A new perspective of human origin and dispersals derived from the microevolution of teeth

Recent genetic studies have heightened the expectation that the origin of modern humans will be defined, but one clear vision has yet to be developed. The study of teeth has historically been an informative means to help define human dispersals. Quantitative tooth data is presented encompassing worldwide human populations. A null hypothesis phylogeny developed from the multivariate analysis of the microevolution of the dental phenotype was interpreted to be broadly in accord with the dominant interpretation of genetic, archaeological, and other dental data by showing that the first division in the dispersion of extant humanity was within sub-Sahara Africans; i.e., San, and Western Africans and Bantu. This "out-of-Africa" interpretation of the graphical results suggests that the first modern human African emigrants not to go extinct were Southeast Asian Negritos. All Eurasians then emerged and expanded through a series of extinct antecedent populations branching from the short lineage extending from Negritos to Australian aborigines. Caucasoids were the first group to fission from this stock. Under this hypothesis, the next to have emerged were antecedent Southeast Asians, from which present Southeast Asians and then antecedent east Central Asians then diverged. Independently, people from the region of Mongolia and all Native Americans arose as daughter populations from antecedent east Central Asians. The broad outline of humanity studied here cannot disprove the equally explanatory protean multiregional hypotheses, but with the inclusion of hominids and further modern human populations either parts of the multiregional hypothesis or the outlined more linear evolutionary scenario likely can be refuted.     

Dental perspectives on the population history of Southeast Asia

This article uses metric and nonmetric dental data to test the "two-layer" or immigration hypothesis whereby Southeast Asia was initially occupied by an "Australo-Melanesian" population that later underwent substantial genetic admixture with East Asian immigrants associated with the spread of agriculture from the Neolithic period onwards. We examined teeth from 4,002 individuals comprising 42 prehistoric and historic samples from East Asia, Southeast Asia, Australia, and Melanesia. For the odontometric analysis, dental size proportions were compared using factor analysis and Q-mode correlation coefficients, and overall tooth size was also compared between population samples. Nonmetric population affinities were estimated by Smith's distances, using the frequencies of 16 tooth traits. The results of both the metric and nonmetric analyses demonstrate close affinities between recent Australo-Melanesian samples and samples representing early Southeast Asia, such as the Early to Middle Holocene series from Vietnam, Malaysia, and Flores. In contrast, the dental characteristics of most modern Southeast Asians exhibit a mixture of traits associated with East Asians and Australo-Melanesians, suggesting that these populations were genetically influenced by immigrants from East Asia. East Asian metric and/or nonmetric traits are also found in some prehistoric samples from Southeast Asia such as Ban Kao (Thailand), implying that immigration probably began in the early Neolithic. Much clearer influence of East Asian immigration was found in Early Metal Age Vietnamese and Sulawesi samples. Although the results of this study are consistent with the immigration hypothesis, analysis of additional Neolithic samples is needed to determine the exact timing of population dispersals into Southeast Asia.     

Genetic affinities of oceanic populations based on RFLP and haplotype analysis of genetic loci on three chromosomes.

Restriction fragment length polymorphisms at the renin and factor 13B loci located at chromosome 1q32-1q42 were studied in 14 ethnic groups in the west Pacific region. The allele frequencies were combined with previously described beta-globin and albumin-vitamin D binding protein haplotype frequencies and used to assess genetic affinities among eight major ethnic-geographic groups in this region. These population groups divide into two clusters with Australian Aborigines, Island Melanesians, and Highland Melanesians forming one cluster and east Asians, Southeast Asians, Micronesians, and Polynesians forming the other. The results indicate that Micronesians and Polynesians are derived from populations in Southeast Asia and that they originated independently of the Melanesian populations.     

中国早期智人牙齿化石

中国目前较为可靠的早期智人牙齿材料应包括在巢县、许家窑、长阳、周口店新洞和桐梓发现的人类牙齿化石,代表一类与早期组早期智人相当或十分相近的古人类。丁村人类牙齿化石可能是代表晚期组早期智人也可能是代表解剖学上的现代智人。就牙齿材料而言,尚无充分的证据能表明在中国曾同时存在过两种类型的早期智人。     

Evolution of beta-globin haplotypes in human populations

The beta-globin haplotypes of 852 chromosomes from 12 populations in the Asia-Pacific region are described. These data are combined with those from other populations in an investigation of the affinities of regional human populations. Both partial maximum-likelihood and distance Wagner methods indicate that Africans are the most divergent group, with the remaining populations branching in the following order: Australian Aborigines, Highland Melanesians, Lowland Melanesians, Indonesians and Micronesians, Polynesians, east Asians, Indians, and Europeans. This pattern of relationship is consistent with that indicated by other data. Analysis of the evolution and distribution of haplotype occurrence provides some limited support for an origin of modern humans in Africa. Otherwise, however, it was not useful in further elucidating the evolutionary history of human populations.     

Posterior dental size reduction in hominids: The Atapuerca evidence

In order to reassess previous hypotheses concerning dental size reduction of the posterior teeth during Pleistocene human evolution, current fossil dental evidence is examined. This evidence includes the large sample of hominid teeth found in recent excavations (1984–1993) in the Sima de los Huesos Middle Pleistocene cave site of the Sierra de Atapuerca (Burgos, Spain). The lower fourth premolars and molars of the Atapuerca hominids, probably older than 300 Kyr, have dimensions similar to those of modern humans. Further, these hominids share the derived state of other features of the posterior teeth with modern humans, such as a similar relative molar size and frequent absence of the hypoconulid, thus suggesting a possible case of parallelism. We believe that dietary changes allowed size reduction of the posterior teeth during the Middle Pleistocene, and the present evidence suggests that the selective pressures that operated on the size variability of these teeth were less restrictive than what is assumed by previous models of dental reduction. Thus, the causal relationship between tooth size decrease and changes in food-preparation techniques during the Pleistocene should be reconsidered. Moreover, the present evidence indicates that the differential reduction of the molars cannot be explained in terms of restriction of available growth space. The molar crown area measurements of a modern human sample were also investigated. The results of this study, as well as previous similar analyses, suggest that a decrease of the rate of cell proliferation, which affected the later-forming crown regions to a greater extent, may be the biological process responsible for the general and differential dental size reduction that occurred during human evolution. © 1995 Wiley-Liss, Inc.     

Characteristic high- and low-frequency dental traits in sub-Saharan African populations

In an earlier investigation (Irish [1993] Biological Affinities of Late Pleistocene Through Modern African Aboriginal Populations: The Dental Evidence [Ann Arbor: University Microfilms]), biological affinities of 32 sub-Saharan and North African dental samples were estimated using comparative analyses of 36 dental morphological traits. Marked dental homogeneity was revealed among samples within each of the two geographic regions, but significant interregional differences were noted. Assuming dental phenetic expression approximates or is an estimate of genetic variation, the present study of 976 sub-Saharan-affiliated Africans indicates they are not closely related to other world groups; they are characterized by numerous morphologically complex crown and root traits. Turner ([1984] Acta Anthropogenetica 8:23–78; [1985] in R Kirk and E Szathmary (eds.): Out of Asia: Peopling the Americas and the Pacific [Canberra: The Journal of Pacific History], pp. 31–78; [1990] Am. J. Phys. Anthropol. 82:295–318; [1992] Persp. Hum. Biol. 2/Archaeol. Oceania 27:120–127; [1992] in T Akaszawa, K Aoki, and T Kimura (eds.): The Evolution and Dispersal of Modern Humans in Asia [Tokyo: Hokusen-Sha Publishing Co.], pp. 415–438) reports that Northeast Asian/New World sinodonts also have complex teeth relative to Europeans, Southeast Asian sundadonts, Australian/Tasmanians, and Melanesians. However, sinodonty is characterized by UI1 winging, UI1 shoveling, UI1 double shoveling, one-rooted UP1, UM1 enamel extension, M3 agenesis, and three-rooted LM1. Sub-Saharan peoples exhibit very low frequencies of these features. It is proposed that the collection of dental traits which best differentiate sub-Saharan Africans from other worldwide samples includes high frequencies of the Bushman Canine, two-rooted UP1, UM1 Carabelli's trait, three-rooted UM2, LM2 Y-groove pattern, LM1 cusp 7, LP1 Tome's root, two-rooted LM2, UM3 presence, and very low incidences of UI1 double shoveling and UM1 enamel extension. This suite of diagnostic traits is termed the sub-Saharan African dental complex. Am J Phys Anthropol 102:455–467, 1997. © 1997 Wiley-Liss, Inc.     

Ramapithecus and Sivapithecus from China: Some implications for higher primate evolution

The pattern of overall dental dimensions in over 900 teeth of ramapithecines from Lufeng in China is examined using frequency distribution histograms and fitted normal curves, and compared with data for extant hominoids. A prior study has demonstrated unequivocally that at least two groups of animals must have existed at Lufeng [Wu and Oxnard, 1983; Oxnard, 1983a]. The present investigation confirms this finding in more detail. In addition it shows that one fossil group possesses smaller teeth with a lesser degree of sexual dimorphism and approximately equal numbers of adult males and females, and the other possesses larger teeth with a rather larger degree of sexual dimorphism and a female-male ratio that may have approximated from as low as 2:1 to as high as 4:1. Comparisons of patterns of difference along the tooth row demonstrate that both these forms differ from modern apes in their sexual dimorphism, the smaller form being more like humans than the larger, which is more like apes, especially orangutans. Comparisons of the areas of the canine teeth with each of the other functional segments of the tooth row again show that the smaller form is basically similar to modern humans and that the larger resembles extant great apes. Comparisons of other functional dental areas seem to relate to dietary and masticatory functions. Thus the cutting areas are large relative to the chewing areas in omnivorous humans, whereas in the essentially vegetarian great apes this ratio is smaller. The smaller fossil resembles the human condition and may have been somewhat omnivorous; the larger one more resembles the apes and may have been somewhat more vegetarian. However, these comparisons also show that the way in which the larger form resembles the apes is associated with special development of the canines, which is different from that in any modern ape. Comparisons show that the canines in the larger form project far beyond the normal line of tooth crowns. Finally, comparisons show that canine sexual dimorphism in height is marked in the larger form. Neither of these last two features is true of the smaller fossil. These findings have implications for our understanding of the evolution of early pongids and hominids, and for the evolution of primate sexual dimorphisms and dental mechanisms.     

Dental morphology of the Dawenkou Neolithic population in North China: implications for the origin and distribution of Sinodonty

We compare the incidence of 25 nonmetric dental traits of the people of the Neolithic Dawenkou culture (6300-4500 BP) sites in Shandong Province, North China with those of other East Asian populations. The Dawenkou teeth had an overwhelmingly greater resemblance to the Sinodont pattern typical of Northeast Asia than to the Sundadont pattern typical of Southeast Asia. Multidimensional scaling using Smith's mean measure of divergence (MMD) statistic place the Dawenkou sample near the Amur and the North China-Mongolia populations in the area of the plot indicating typical Sinodonty. The existence of the Sinodont population in Neolithic North China suggests a possible continuity of Sinodonty from the Upper Cave population at Zhoukoudian (about 34000-10000 BP) to the modern North Chinese. The presence of Sinodonty in Shandong Province shows that the Japan Sea and East China Sea were strong barriers to gene flow for at least 3000 years, because at this time the Jomonese of Japan were fully Sundadont. In addition, we suggest that the descendants of the Dawenkou population cannot be excluded as one of the source populations that contributed to sinodontification in Japan.