Dental morphology and odontometry of the Tibetan immigrants

Dental features such as size, shape, cusp number and groove pattern, deflecting wrinkle, protostylid, form and size of dental arch and occlusion pattern, as well as crown diameters of maxillary and mandibular dentition of the Tibetan immigrants in India are described. Sex differences in various measurements are also noted. Overall reduction in size, presence of hypodontia of the third molar, and absence of Carabelli's trait are a distinct progressive/evolutionary trend in the Tibetan dentition, while presence of a shovel-shaped lingual surface of central and lateral incisors is a retrogressive/primitive condition. In some of the dental features Tibetans resemble Caucasoid and modern populations, in certain others they resemble other Mongoloid populations, and in still other features they resemble aboriginal populations and fossil hominids.     

Evolutionary and morphological significance of the deflecting wrinkle in the lower molars of the Hominoidea

The deflecting wrinkle is a well-known character state of the lower m2 and M1 of the human dentition, but there is little information regarding its presence in great apes. The deflecting wrinkle is more frequent on M2-3 in all extant pongid genera studied in this paper except Pan paniscus, in which M1 has the highest frequency (16.0%) and in which this wrinkle is absent on M3. In Gorilla, it is absent on M1, with only a low incidence on M2-3. Its greatest frequency in Pongo is always on M2 (20.2%), which is the greatest expression of the trait in the great apes. We interpret the presence of the deflecting wrinkle as an incidental effect and suggest that it represents a plesiomorphic character state in the Hominoidea.     

Sixth and seventh cusp on lower molar teeth of Icelanders

The occurrence of lower molar accessory cusps c6 and c7 is studied in three local populations of known Caucasoid origin in the Northeast of Iceland. The sample comprises 1,010 school-children, 506 boys and 504 girls. The scoring is made from dental stone casts with reference to standard plaques. Only the frequency of c6 on the second deciduous molar is relatively low as expected in a Caucasoid population. Otherwise both c6 and c7 are more common than expected, the frequencies are in fact comparable to those predicted by the Mongoloid dental complex for Mongoloid populations.     

On deflecting wrinkles and the Dryopithecus pattern in human mandibular molars

The utility of the traditional Dryopithecus pattern observations on mandibular molars in hominid dental analysis has been challenged recently from several points of view. Both fossil and contemporary evidence suggest the independence of cusp number and groove pattern on mandibular molars and the quality of dentitions which are normally available for study make it difficult to determine both aspects of pattern (cusp number, groove pattern) equally. Now this paper shows that one of the polymorphisms on the occlusal surface of mandibular molars, the “deflecting wrinkle,” may be responsible for the spurious appearance of a Y molar pattern. It presence serves to insure a “2–3 contact” and hence the identification of the Y molar pattern. While seldom reported in traditional dental data, the wrinkle varies in frequency from 7% in South African white first permanent molars to 78.5% in Bushmen. Elsewhere, Hanihara has proposed that it be considered part of the “Mongoloid dental complex”.     

Deciduous dental morphology and the biological affinities of a late Chalcolithic skeletal series from western India

Morphological variations of the dental crown and roots provide valuable data for determining the genetic affinities and evolutionary adaptedness of prehistoric human skeletal populations. This paper documents morphological variations of a sample of deciduous teeth from the late Chalcolithic farming village of Inamgaon (1600-700 B.C.) in western India. Hanihara's (1963) grading system of deciduous dental traits was employed in assessing the degree of expression of shovel-shape of incisors, cusp number of upper and lower first molars, hypocone variation, Carabelli's trait, cusp number of lower second molars and the protostylid. Turner's (1970) classification was used to determine presence and size of accessory cusps: entoconulid (C-6) and metaconulid (C-7). Comparative evaluation of the Inamgaon deciduous dental data is hampered by the absence of data for dental features of living and prehistoric South Asian populations. Many of the traits observed in the Inamgaon series exhibit a frequency of occurrence intermediate between figures characteristic of the "Mongoloid" dental complex and the "Caucasoid" dental complex.     

Logistic analysis of the effects of shovel trait on Carabelli's trait in a mongoloid population

Mongoloid populations differ from Caucasoids by having a high prevalence of shovel trait and a low prevalence of Carabelli's trait. This study was conducted to investigate the effects of the shovel trait on Carabelli's trait in a Mongoloid population. The research design sought a population that resides in an isolated area and exhibits low admixture with neighboring populations. The Mongoloid group selected for study was the Bunun tribe of aborigines who inhabit an alpine area in Taiwan. The effects of sex and age on Carabelli's trait were controlled in this investigation, as was the association between tooth size and Carabelli's trait. Results show that males were more likely to have Carabelli's trait expressed on teeth than females. The buccolingual diameter of Carabelli's trait teeth was larger than that of teeth without the trait. After adjusting for sex, age, and tooth size, the existence of the shovel trait increased the likelihood of having Carabelli's trait by a factor of three, an effect that is significant. © 1996 Wiley-Liss, Inc.     

Evolution of the dentition in prehistoric Ohio Valley Native Americans: II. morphology of the deciduous dentition

In order to evaluate the microevolutionary dynamics of morphological features of the deciduous dentition, I collected data on the variation of 57 features (33 crown and 24 root) from prehistoric Ohio Valley populations. I sampled a total of 370 individuals from 26 populations representing a lineage that inhabited the middle and upper Ohio valley region from approximately 3000 to 350 BP. Evolutionary changes in the frequencies of morphological features of the deciduous teeth in this lineage were limited. Over 80% of the features show no significant differences among the populations. The relatively few features that show consistent differences separate pre- and postmaize agricultural populations. I discuss explanations for this change in terms of selection differences or gene flow. The general pattern of morphological trait expression in the deciduous teeth of this Ohio Valley lineage corresponds to what has been termed the Mongoloid dental complex (sinodonty in the permanent teeth). I suggest additional features that, with further study, may be added to this morphological complex. Am J Phys Anthropol 106:189–205, 1998. © 1998 Wiley-Liss, Inc.     

Nonmetric tooth crown traits in a Sri Lankan aboriginal Vedda population

This study was conducted to determine the frequencies of non-metric tooth crown traits of Vedda of Sri Lanka and to investigate the affinities of these morphological variations with those of other world populations.Fifty dental plaster casts were observed. The Arizona State University dental anthropology system was adopted for classification of the 16 traits observed. We used 13 traits to compare the Vedda and other world populations. Using the frequencies of 13 traits, Smith Mean Measure of Divergence was calculated to determine inter-population distances. Affinities among the Vedda and other world populations were expressed in two dimensions of the principal coordinate analysis.Cusp number in mandibular second molar and hypocone absence in maxillary second molar had the highest frequency at 95.9% and 93.8%, respectively. Shovelling, double shovelling in the maxillary central incisor and deflecting wrinkle in the mandibular first molar had the lowest frequency at 0%. The principal coordinate analysis showed that Sino American and Western Eurasian populations were separated in negative and positive directions in the first principal coordinate axis. Vedda located with the Western Eurasian population groups. Sahul and Sunda Pacific populations located in the intermediate position between Sino American and Western Eurasian populations.The dental phenotype of Vedda has close affinities with those of early south Asian populations. They are far different from Sino American and Sunda pacific populations. Vedda shows closer affinities to Sahul Pacific and South African (Bantu) populations.     

Negritos, Australian aborigines, and the "proto-sundadont" dental pattern: the basic populations in east Asia, V.

Five evolutionarily significant dental traits were identified from a B-square distance analysis of nine crown characters recorded for several populations of East Asia and Oceania. Intergroup variation in these traits distinguishes three major divisions of the Mongoloid dental complex: sundadonty, sinodonty, and the dental pattern of Australian Aborigines. The Australian crown features may be characterized as having high frequencies of evolutionarily conservative characters. Negritos, one of the probable representatives of indigenous inhabitants of Southeast Asia who may have shared a common ancestor with Australians, possess the more derived sundadont dental pattern. As far as the five crown traits treated here are concerned, Australian dental features may be described as conforming to a "proto-sundadont" dental pattern, applying Turner's terminology. This pattern may represent a microevolutionary step prior to the emergence of the sundadont and sinodont patterns.     

湖北长阳青铜时代人类乳齿特征的研究

对在湖北长阳县深潭湾崖葬墓出土的青铜时代人类乳齿形态特征的观察研究显示在人类恒齿出现的大多数具有种族识别价值的形态特征在乳齿有相等程度的表现,其中部分特征的出现率和表现程度高于恒齿。与其他地区人群相比,长阳青铜时代人类乳齿特征在总体上与东北亚人类具有的“中国型牙齿”特征接近。同时,在个别牙齿特征上呈现出南亚蒙古人种的特点。作者对产生这种现象的原因进行了分析。本文还就长阳青铜时代人类乳齿测量数据的表现特点进行了探讨。     

Incidence of cleft chin among the Adi and Apatani of Arunachal Pradesh, Northeast India

The occurrence of cleft chin was studied among five endogamous groups (Padam, Minyong, Pasi, Gallong, Apatani) of Arunachal Pradesh, Northeast India. The incidence of this trait is low in all the groups. Thus, the populations are characterized by low frequencies of the gene Cl. Bisexual difference is significant only among the Minyong. While compared with other populations from Northeast India, the Mongoloid populations were found to be distinct from the only caste population, which has been investigated so far.     

Morphological features of Jat dentition

Observations on morphological characters of milk and permanent teeth, based on 648 pairs of dental casts of 356 male and 292 female Jat children of Haryana (India) are reported. Deciduous teeth show high frequencies of bilateral winging of maxillary central incisor, Carabelli's cusp of maxillary second molar, and deflecting wrinkle of mandibular second molar. Reduction of maxillary molar cusps is more marked in males than in females. Y pattern is very common in deciduous molars. Permanent teeth have high frequencies of grooved cingulum of incisors, cingular nodule of lateral incisors and canines, and distal accessary ridge of canines. Low frequencies of Carabelli's cusp and winging are also common. The tendency towards faintly developed shovelling in milk incisors occurs more often than in the permanent teeth.     

The dentition of the Lengua Indians of Paraguay

The crown morphology of 202 dental casts from living Lengua Indians is described and compared with other Amerind, Melanesian, and Caucasoid samples. The Lengua dentition shows a high Mongoloid component with little effects of possible European admixture, thus supporting the theory that despite early Franciscan and Jesuit attempts at missionization, much of the Paraguayan Chaco has remained genetically and culturally relatively intact well into the present century. A finding of note was the apparent sexual dimorphism of the Carabelli cusp, which questions earlier assumptions that no correction for sex need be made in population studies when dealing with this trait. Since mandibular canines show proportionately less wear in the canine distal accessory ridge area than maxillary canines, the value of the incidence of this trait in population and microevolutionary studies is questioned.     

The blood groups of the Timuri and related tribes in Afghanistan

The present investigation is a study of the blood groups of the Timuri and related tribes in Afghanistan. There is little historical documentation for the origin of the Timuri. Their name is probably a misnomer, however, since they are apparently not descended from the armies of Timur, or Tamerlane, which invaded Afghanistan during the fourteenth century. Relatively few blood group studies have been carried out on the inhabitants of Afghanistan, so detailed comparisons with other populations can be made only for the ABO system. (Certain populations in Iran to the west and a few rather widely separated populations, such as the Baltis and Nepalis to the east, have been more thoroughly investigated, and comparisons can be made with them on at least seven genetical systems.) The presence of the A₂ allele suggests gene flow from the West, but the high frequency of B is consistent with other populations tested in Afghanistan. The Rh frequencies give little critical information but the low level of cde is suggestive of Mongoloid origin. On the other hand, for the MNS system the high level of MS is typically Caucasoid. The high total M is found in Asia both in Caucasoids and Mongoloids. The presence of the Lu^a allele and the relatively high frequency of the K allele are more Caucasoid than Mongoloid, but the presence of even one Diego (Di^a) positive among the Timuri and related tribes suggests a Mongoloid contribution to the gene pool. The low frequency of P₁, though always a little suspect on travelled specimens, is consistent with this. All of the Iranian populations tested may be regarded as essentially Caucasoid from the blood group point of view. The Baltis and Nepalis show certain Mongoloid characteristics. The Timuri are distinctly more Mongoloid than the former but less so than the latter. In summary, the Timuri appear to be intermediate in allele frequencies between Caucasoid and Mongoloid populations, with unmistakable evidence of both in their ancestry.     

A genetic study on the Newards of Nepal valley

The intergroup differences between the three groups of Newars of Nepal (Shrestha, Gubhaju and Jyapu) are not significant for any of the morphological and genetical characters studied. In body measurements the Newars on the whole are similar to other Nepali populations and to several populations of the western and northeastern Himalayas. In serological characters the Newars resemble the Nepalis as well as many of the Himalayan and Assam tribal populations. In mid-phalangeal hair, phenyltheourea tasting ability and colour-blindness the Newars are similar to several Cis-Himalayan groups. In dermatoglyphic traits, the Newars are close to some Mongoloid populations of the Far East and several populations with Mongoloid affinities residing in the western Himalayas.     

Major features of Sundadonty and Sinodonty, including suggestions about East Asian microevolution, population history, and late Pleistocene relationships with Australian aboriginals

The eight diagnostic morphological traits of the Sundadont and Sinodont divisions of the Mongoloid dental complex are identified. Intra- and intergroup variation for these crown and root features is plotted. The univariate frequency distributions provide useful evidence for several suggestions about East Asian prehistory, dental microevolution, and intergroup relationships. The case for local evolution of Sundadonty is strengthened by finding Australian teeth to be very similar to this pattern. Australian Aboriginal teeth are also generally like those of Jomonese and some Ainus, suggesting that members of the late Pleistocene Sundaland population could have initially colonized Sahulland as well as the continental shelf of East Asia northward to Hokkaido.     

Observer error,dental wear,and the inference of new world sundadonty

Dental morphology provides important information on human evolution and interpopulation relationships. Dental wear is one of the major limitations of morphological data analysis. Wear figures heavily in existing debates about patterns of New World dental variation with some scholars finding evidence for a more generalized dentition in early New World populations (Powell: Doctoral Dissertation, Texas A&M University, TX (1995)) and others questioning these findings based on the probable effects of dental wear on trait scores (Turner, The First Americans: the Pleistocene Colonization of the New World. San Francisco: California Academy of Sciences (2002) 123–158; Turner: Am J Phys Anthropol 130 (2006) 455–461; Turner and Scott, Handbook of paleoanthropology, Vol. III: Phylogeny of Hominids. New York: Springer (2007) 1901–1941). Here we evaluate these competing claims using data from the Early Archaic Windover sample. Results confirm the dental distinctiveness of Windover with respect to other Old World Asian (i.e., sinodont/sundadont) populations. However, comparison of our results to those of Powell (1995) also highlights significant interobserver error. Statistical analysis of matched wear and morphology scores suggests trait downgrading for some traits. Patterns of missing data present a more challenging (and potentially serious) problem. Use of Little's MCAR test for missing data mechanisms indicates a complex process of data collection in which incidental and opportunistic recording of both highly worn and unerupted teeth introduce a “missing not at random” mechanism into our dataset that biases dental trait frequencies. We conclude that patterns of missingness and formal research designs for “planned missingness” are needed to help mitigate this bias. Am J Phys Anthropol 156:349–362, 2015. © 2014 Wiley Periodicals, Inc.     

中国人免疫球蛋白同种异型的研究:中华民族起源的一个假说

调查了我国24个民族、74个群体的免疫球蛋白同种异型Gm、Km分布。测定了9560例个体的Gm(1,2,3,5,21)因子和9611例个体的Km(1)因子。根据Gm单体型频率计算了遗传距离并绘制了系统树。结果支持作者早前提出的有关中华民族起源于古代两个不同群体的假说。这两个群体大致以北纬30度为界,分别居栖在黄河和长江流域。本文数据和其他主要人种的Gm分布资料相比较,作者认为在人类进化中,尼格鲁人种首先和高加索-蒙古人种分离;然后高加索人种和蒙古人种分离。不同人种间的差异,大于同一人种内不同群体间的差异。蒙古人种明显地被分为南、北两大类型,分别以具有高频率的Gm~(1;21)和Gm~(1,3;5)单体型作为种族的标记。与高加索人种关联的Gm~(3;5)单体型存在于中国西北地区的少数民族中,提示混有高加索人种血缘。很可能来源于中亚地区的高加索人,通过“丝绸之路”进入中国。Km因子在所调查的74个群体中呈随机分布。     

Shortened fifth medial phalanges

A radiographic study was made of the left fifth medial phalanges of 200 Philadelphia Negro and 96 Chinese children. Twelve cases of abnormal shortening of this bone (defined, for the present, as less than half the length of the fourth medial phalanx) were found in the Chinese sample, while none were found in the Negroes. This trait, brachymesophalangy 5, in general seems to be characterized by short but well proportioned diaphyses and cone-shaped epiphyses with very early union. Population surveys reported in the literature indicate that this trait is considerably more common in Mongoloid and American Indian populations than in Whites or Negroes. The mode of inheritance of this genetic trait is uncertain, but present evidence indicates that it may be a simple autosomal recessive.