Nonmetric Cranial Traits Research Articles

The Ainu and their neighbors as seen from the perspective of nonmetric cranial trait variation

The Ainu and their neighbors as seen from the perspective of nonmetric cranial trait variation

Population history of northern Vietnamese inferred from nonmetric cranial trait variation

In this study, nine nonmetric cranial traits were recorded for ancient human remains exca- vated at early prehistoric (the late Pleistocene, early Holocene, and Pre-Pottery Neolithic) and late pre- historic (the Neolithic and early Iron age) archeological sites in northern Vietnam. The comparative samples consist of prehistoric and early historic crania from the lower Yangtze River basin, together with recent cranial series from Vietnam, Thailand, South China, and Australia. The results, based mainly on the measure of divergence, are as follows: (1) the early prehistoric northern Vietnam group is distinct from the subsequent inhabitants of northern Vietnam and neighboring populations; (2) the cranial series of northern Vietnam and the surrounding region from the late prehistoric to recent times through early historic period exhibit relative homogeneity, suggesting population continuity; (3) the re- cent Han Chinese from southern China, one of the possible representatives of East Asians, are rela- tively distant from all groups from the prehistoric age onwards; and (4) a clear separation of Aboriginal Australians from all the comparative samples, including the early prehistoric northern Vietnamese, is evident. These findings suggest partial support for the two opposing hypotheses, i.e. the two-layer model and the regional-continuity model, for the population history of Southeast Asians, at least, in the northern Vietnamese region. This may be further compatible with the recent hypothesis for modern human dispersals: an earlier out-of-Africa expansion of Australians than other contemporary Eurasians including Southeast Asians.

The Ainu and their neighbors as seen from the perspective of nonmetric cranial trait variation

北海道アイヌの成立には，オホーツク人の遺伝的影響がかなり強く及んでいたという近年の研究成果に鑑みて，視野の中心を北海道に据えて，東アジアと北東アジアにおける北海道アイヌの人類学的位置を，頭蓋の形態小変異を指標にして，概観してみた。使用した形態小変異は観察者間誤差の少ない9項目で，日本列島の10集団とサハリンおよび大陸北東アジアの3集団を対象に分析を行った。集団間の親疎関係の推定にはスミスの距離（MMD）を用い，棒グラフとMMDマトリックスの主座標分析で集団間の相互関係を図示した。オホーツク人は北海道アイヌとサハリン・アムール・バイカルといった北東アジア集団のほぼ中間に位置したが，北海道アイヌとの形態距離はかなり近く，北海道や本州の縄文人と同程度であった。これに対して，大陸東アジアにその原郷が求められる弥生系集団は，北海道アイヌから遠く離れていた。9項目による分析結果が妥当なものであったかどうかを検証し，さらに，北海道の続縄文人の形態学的な位置づけを明らかにするために，著者のひとりが独自にデータを収集した12集団についても，20項目の形態小変異を用いて，同様の分析を行った。9項目による分析結果と20項目による分析結果はほとんど同じで，北海道アイヌの母体になった集団は，やはり従来の指摘どおり，北海道や本州の縄文人と北海道の続縄文人であると考えられたが，北海道アイヌの成立には，オホーツク人の遺伝的影響をも考慮しなければならないと思われる。

The Ainu and their neighbors as seen from the perspective of nonmetric cranial trait variation

北海道の南西部，中央部，および北東部のアイヌにサハリンアイヌを加えたアイヌ4地域集団を対象にして，日本本土と琉球諸島諸集団の地域差と比較しながら，アイヌの地域差とはいったいどの程度のものであったのかを，頭蓋形態小変異20項目を指標にして評価してみた。地域差の大小関係は，スミスの距離（MMD）を尺度として比較した。北海道アイヌ3集団の地域差の程度は，奄美・沖縄・先島の琉球諸島近世人3集団の地域差よりはやや大きく，東北・関東・九州の日本本土の現代人3集団の地域差とほぼ同程度であった。北海道アイヌのなかでは，道北東部アイヌが道南西部および道中央部のアイヌとやや距離を置く傾向が観察された。サハリンアイヌは北海道アイヌから相当程度遠く離れ，その距離（MMD）の平均値は，北海道アイヌ3地域集団相互の距離の平均値の約4倍にも達した。このような関係は，18項目の頭蓋計測値にもとづいたマハラノビスの距離（D2）でも確かめられた。

Sahara: Barrier or corridor? Nonmetric cranial traits and biological affinities of North African late holocene populations

The Garamantes flourished in southwestern Libya, in the core of the Sahara Desert ~3,000 years ago and largely controlled trans-Saharan trade. Their biological affinities to other North African populations, including the Egyptian, Algerian, Tunisian and Sudanese, roughly contemporary to them, are examined by means of cranial nonmetric traits using the Mean Measure of Divergence and Mahalanobis D(2) distance. The aim is to shed light on the extent to which the Sahara Desert inhibited extensive population movements and gene flow. Our results show that the Garamantes possess distant affinities to their neighbors. This relationship may be due to the Central Sahara forming a barrier among groups, despite the archaeological evidence for extended networks of contact. The role of the Sahara as a barrier is further corroborated by the significant correlation between the Mahalanobis D(2) distance and geographic distance between the Garamantes and the other populations under study. In contrast, no clear pattern was observed when all North African populations were examined, indicating that there was no uniform gene flow in the region.

An evaluation of non-metric cranial traits used to estimate ancestry in a South African sample

Establishing ancestry from a skeleton for forensic purposes has been shown to be difficult. The purpose of this paper is to address the application of thirteen non-metric traits to estimate ancestry in three South African groups, namely White, Black and "Coloured". In doing so, the frequency distribution of thirteen non-metric traits among South Africans are presented; the relationship of these non-metric traits with ancestry, sex, age at death are evaluated; and Kappa statistics are utilized to assess the inter and intra-rater reliability. Crania of 520 known individuals were obtained from four skeletal samples in South Africa: the Pretoria Bone Collection, the Raymond A. Dart Collection, the Kirsten Collection and the Student Bone Collection from the University of the Free State. Average age at death was 51, with an age range between 18 and 90. Thirteen commonly used non-metric traits from the face and jaw were scored; definition and illustrations were taken from Hefner, Bass and Hauser and De Stephano. Frequency distributions, ordinal regression and Cohen's Kappa statistics were performed as a means to assess population variation and repeatability. Frequency distributions were highly variable among South Africans. Twelve of the 13 variables had a statistically significant relationship with ancestry. Sex significantly affected only one variable, inter-orbital breadth, and age at death affected two (anterior nasal spine and alveolar prognathism). The interaction of ancestry and sex independently affected three variables (nasal bone contour, nasal breadth, and interorbital breadth). Seven traits had moderate to excellent repeatability, while poor scoring consistency was noted for six variables. Difficulties in repeating several of the trait scores may require either a need for refinement of the definitions, or these character states may not adequately describe the observable morphology in the population. The application of the traditional experience-based approach for estimating ancestry in forensic case work is problematic.

Advanced CT images reveal nonmetric cranial variations in living humans

Two mainland Japanese males were examined with a computer tomography (CT) X-ray scanner to reconstruct three-dimensional CT simulation images of their cranial anatomy and to check for the presence/absence of 23 nonmetric cranial traits. Surface anatomy for scoring 19 nonmetric cra- nial variations was clearly observed among the 23 variations. Evaluation of the four other traits might have been disturbed due to dental treatment history, small variations in the images, or X-ray radiation condition. However, these disturbances could be overcome by a combination of simple thin-sliced CT images and magnetic resonance imaging. We have thus developed a new anatomical field for eluci- dating human morphology.

Nonmetric cranial variation of Jomon Japan: Implications for the evolution of eastern Asian diversity

The purpose of this study is to investigate the origin and expansion of the Jomon population, the Neolithic inhabitants of the Japanese archipelago, and peopling East/Northeast Asian region through a global comparison between the prehistoric samples from around the world. R-matrix approach was applied to 20 nonmetric cranial traits for assessing the population structure and history of the Jomon. Pattern of ancient group relationships on a global scale was presented using network splitstree applied to distance matrix transformed from the R-matrix. The phenotypic variation is largest in Hokkaido region, followed by the regions of eastern Japan. The Chugoku region, the southwestern part of Japan, shows larger variance than eastern Japan. Global analyses including samples from Northeast Asia, Southeast Asia, Australia, West Asia, Europe, and North Africa dating roughly to the same chronological periods as those of the Jomon groups, indicate northern affinities of the Jomon and the distinction between Southeast and Northeast Asian series. The Jomon ancestors of the northern part of Japan might have expanded southward to Honshu Island with a series of bottlenecks. A possible gene flow from outside source or heterogeneous origin of western Jomon group was, at the same time, suggested. The network relationships of the Jomon with Northeast Asians and, to a lesser extent, with Southeast Asians based on the splitstree analysis may allow us to suppose that the Jomon may be one of the key populations for the studies of the evolution of eastern Asian diversity.

An examination of Nubian and Egyptian biological distances: Support for biological diffusion or in situ development?

Many authors have speculated on Nubian biological evolution. Because of the contact Nubians had with other peoples, migration and/or invasion (biological diffusion) were originally thought to be the biological mechanism for skeletal changes in Nubians. Later, a new hypothesis was put forth, the in situ hypothesis. The new hypothesis postulated that Nubians evolved in situ, without much genetic influence from foreign populations. This study examined 12 Egyptian and Nubian groups in an effort to explore the relationship between the two populations and to test the in situ hypothesis. Data from nine cranial nonmetric traits were assessed for an estimate of biological distance, using Mahalanobis D 2 with a tetrachoric matrix. The distance scores were then input into principal coordinates analysis (PCO) to depict the relationships between the two populations. PCO detected 60% of the variation in the first two principal coordinates. A plot of the distance scores revealed only one cluster; the Nubian and Egyptian groups clustered together. The grouping of the Nubians and Egyptians indicates there may have been some sort of gene flow between these groups of Nubians and Egyptians. However, common adaptation to similar environments may also be responsible for this pattern. Although the predominant results in this study appear to support the biological diffusion hypothesis, the in situ hypothesis was not completely negated.

Who were the Meroites? A biological investigation into the Nubian post-hiatus group

Scholars have identified a hiatus in the archaeological record of Lower Nubia that spans approximately 1000 years. This interval may represent a desertion of Lower Nubia by its inhabitants. Evidence of occupation did not reappear in the area until the Meroitic time period. However, the identity of the returning people has been the subject of speculation. In order to determine who the Meroites of Lower Nubia were, 20 cranial non-metric traits were observed on six Nubian groups, representing five time periods. Two groups date to time periods immediately before (Kerma) and immediately after (X-Group) the Meroitic period. Three additional Nubian groups (two Christian samples from different sites and Sesebi, a contemporary sample) were utilised as outgroups to elucidate a clearer picture of the relationship among the six samples. Mahalanobis D2 with a tetrachoric matrix was employed for calculating biological distances among the groups. Principal coordinates analysis produced two clusters of Nubians, where the Meroitics clustered with other Nubian groups. Specific distance scores indicate the Meroites were biologically similar to individuals from the time periods prior to and after their arrival in Lower Nubia. The Meroites therefore appear to be a Nubian group returning to Lower Nubia after its desertion. Copyright © 2009 John Wiley & Sons, Ltd.

Nonmetric cranial variation in human skeletal remains associated with Okhotsk culture

Population affinities and biological variation in human skeletal series associated with the Okhotsk culture from Hokkaido and Sakhalin Islands from the 5th to 12th centuries AD are investigated using 19 nonmetric cranial traits. The Okhotsk crania have a higher frequency of the supraorbital foramen than the Hokkaido Ainu and Jomon, while the frequency of the transverse zygomatic suture vestige in the Okhotsk is as high as in the Jomon. The mean measure of divergence between the northern and eastern Okhotsk cranial assemblages is small and insignificant. The method of Relethford and Blangero [Relethford J.H. and Blangero J. (1990) Human Biology, 62: 5–25] suggests that the eastern Okhotsk had a larger Rii value (distance from the centroid) and a lower observed variation than the northern Okhotsk, indicating that the eastern Okhotsk lost phenotypic variability. These results further reaffirm the affinity between the Okhotsk skeletal series and Northeast Asian series such as the Neolithic Baikalian and Amur. Finally, the results of analyses of nonmetric cranial variation demonstrate a close relationship between the Okhotsk, Ainu, and Jomon series that suggests that the Jomon and Ainu were closer to the Okhotsk than to other Northeast Asian series prior to any admixture.

The influence of artificial cranial vault deformation on the expression of cranial nonmetric traits: Its importance in the study of evolutionary relationships

Nonmetric cranial traits have been commonly used in evolutionary relationship studies. They develop during the growth and development of an individual, and for this reason its expression presents different sources of genetic and nongenetic variation. However, the use of these features in evolutionary relationship studies carries the implicit assumption that much of the nonmetric trait variation is essentially genetic. Among the nonheritable factors, cranial vault deformation has been the most studied in human populations. Because of the widespread distribution and elevated rate of artificial cranial vault deformation found in America, and the importance of nonmetric traits in evolutionary relationship studies in this area, the objectives of this paper are as follows: (a) to study the influence of artificial cranial vault deformation on the presence of nonmetric traits within samples of human craniofacial remains; and (b) to establish artificial cranial vault deformation influence on evolutionary relationships between local populations on a regional scale. Our results indicate that artificial cranial vault deformations alter the variation and covariation of metric and nonmetric traits in some samples. Wormian bones, placed in cranial vault sutures, are the most influenced by this factor. However, our results suggest that when all nonmetric traits were used the artificial cranial vault deformation did not influence the basic pattern of variation among samples. The exclusion or inclusion of wormians bones in evolutionary relationships analysis did not modify the results, but using only wormians bones lead to inconsistent results indicating that these traits have little value on these kind of studies.

Ethnogenesis and craniofacial change in Japan from the perspective of nonmetric traits

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.

Why are rare traits unilaterally expressed?: Trait frequency and unilateral expression for cranial nonmetric traits in humans

Based on an analysis of nonmetric trait databases from several large skeletal series in Northern Europe and South America, representing 27 bilateral traits, we report a predictable relationship between the frequency of nonmetric traits and the probability that they are expressed bilaterally. In a wider sampling of traits and populations, this study thus confirms the findings of an earlier study by Ossenberg ([1981] Am. J. Phys. Anthropol. 54:471-479), which reported the same relationship for two mandibular traits. This trend was previously explained by extending the multifactorial threshold model for discontinuous traits to incorporate either separate thresholds for unilateral or bilateral expression, or by a fuzzy threshold in which the probability of bilateral expression increases away from the median threshold value. We show that the trend is produced under the standard multifactorial threshold model for discontinuous traits simply if the within-individual or developmental instability variance remains relatively constant across the range of liability. Under this assumption, the number of individuals in which one side but not the other is pushed over the threshold for trait formation will be a larger proportion of the number of individuals expressing the trait when the trait frequency is low. As trait frequency increases, the significance of within-individual variance as a determinant of trait formation decreases relative to the genetic and among-individual environmental variance. These results have implications for interpreting nonmetric trait data as well as for understanding the prevalence of unilateral vs. bilateral expression of a wide variety of discontinuous traits, including dysmorphologies in humans.

Morphological affinities between Jomon and Ainu: reassessment based on nonmetric cranial traits

This study reevaluates the relationship between the prehistoric Jomon and modern Ainu based on 18 nonmetric cranial traits. Although the two Ainu series from the northeast coast and central/southern regions of Hokkaido Island are always associated with Jomon, significant differences between the Ainu and Jomon were detected in the frequencies of seven traits: metopism, supraorbital foramen, ovale–spinosum confluence, hypoglossal canal bridging, jugular foramen bridging, biasterionic suture vestige, and occipitomastoid bone. Regarding these traits, the Ainu series are more similar to the Okhotsk than to the Jomon series. A broad comparison among pan-Pacific populations confirms the maintenance of distinctive morphologies in the remote regions of group ranges, as represented by the Jomon and to a lesser extent the recent Hokkaido Ainu. The Ainu occupies an intermediate position between Jomon and Northeast Asians on the one hand, and between Jomon and the Native Americans on the other. The pattern of temporal change between Jomon and Ainu, together with clinal variation among the three Ainu series from Sakhalin Island, the northeast Hokkaido coast, and central/south Hokkaido shown in the present study, indicate possible admixture between the ancestors of recent Ainu and northern groups such as the Okhotsk people in the post-Jomon periods.

On the Origin of the Armenians (in the Light of Non-metric Cranial Traits Data)

The problem of the origin of the Armenian ethnicity has been highlighted in numerous scholarly publications. Many archaeological data corroborate the cultural continuity between the current and ancient populations of Armenia extending at least down to the period of early Iron Age. 1 In effect, the formation of the physical type of Armenians had been deeply rooted in a grey antiquity and is closely associated with the formation of the Armenoid anthropological type embracing many populations of the Near East and the Caucasus, as well as the majority of the Armenian nation. The Armenoid type is characterised by a slightly wavy hair, a developed tertiary integument, with abundant facial hair, dark complexion, dark eyes and hair, a peculiarly shaped nose with a dropped tip, wide and elevated nose wings, moderately thick lips, narrowly cut eyes, medium-size rather elevated face, brachycranial, very elevated skull, often with a very inclined forehead and a flat back of the head. The origin of the Armenoid type is very interesting with regard to complicated ethno-genetic processes within the Near East and the Caucasus, as well as to the historical antiquity of the peoples of these regions and their proximity to the centres of the world civilisation. According to Debec: ... there can be no serious ethno-genetic study of the European and Near Eastern peoples that would skip references to the peoples of the Caucasus.2

Non-metric morphological divergence in the western house mouse, Mus musculus domesticus, from the Barcelona chromosomal hybrid zone

The effect of hybridization on morphological variation was investigated in 120 western house mice, Mus musculus domesticus, from the hybrid zone between the Barcelona and standard chromosomal races. The incidence of 37 non-metric cranial traits was calculated for standard mice (2n = 40) and Barcelona-standard hybrids (2n = 27–39). Subsequent analyses were conducted on several karyological subgroups, established by grouping the animals according to either their diploid number or their degree of chromosomal heterozygosity. Results revealed no significant difference by sex, asymmetry, or geographical distance. Significant phenetic divergences were found between the karyotypes studied in relation to several variants. Differences were especially substantial between the standard race and hybrid mice, even with respect to those hybrids with karyotypes close to that of the standard race. Within the hybrids, the maximum divergence corresponded to the 28-chromosome homozygotes, chromosomally close to the Barcelona race, and to the heterozygotes with more than two fusions. Since differences in non-metric trait frequencies are generally considered a measure of genetic divergence, the results suggest the occurrence of a barrier to gene flow in the Barcelona hybrid zone. The decrease of genetic exchange between the chromosomally differentiated mice might be due to reduced fertility in hybrids, associated with chromosomal heterozygosity. © 2003 The Linnean Society of London, Biological Journal of the Linnean Society, 2003, 80, 313–322.

Nonmetric cranial trait variation and prehistoric biocultural change in the Azapa Valley, Chile

Historically, interpretations of both biological and cultural change within the prehistoric Azapa Valley, northern Chile, have cited large-scale population movements, with replacement from complex societies located in the adjacent highlands to the east. Biological estimates of this change have traditionally relied upon biodistance estimates, using craniofacial measures of both deformed and nondeformed skulls. In order to evaluate whether large-scale prehistoric migrations occurred in the Azapa Valley, we examine biodistance results from nonmetric cranial traits for eight mortuary samples that represent all time periods of prehistoric occupation of the valley. None of the mean measures of divergences (MMD) among mortuary samples examined by this study were significant. These results suggest biological continuity in the Azapa Valley during 5,000 years of prehistory, with nonsignificant gene flow during the late Middle Horizon (AD 750-1100) and Late Intermediate (AD 1100-1476) periods. Biodistance results also suggest endogamy within coastal and inland populations. The broader implications of these results are discussed.

Phenogenetic Analysis of Pygmy Wood Mouse (Apodemus uralensis Pall.) Populations in the Zone of the Eastern Ural Radioactive Trace (EURT)

Monitoring of A. uralensis populations in Kamenskii raion, Sverdlovsk oblast, in 1992–2002 and in Kaslinskii raion, Chelyabinsk oblast, in 2000–2001 revealed an increase in the proportion and diversity of minor morphogenetic aberrations and abnormalities in the structure of the cranium along the axis of the Eastern Ural Radioactive Trace (EURT). The samples from the southern and northern parts of the EURT (contaminated with 90Sr to 500 and 4 Ci/km2, respectively) were characterized by directed deviations from the control with respect to the frequencies of phenes of nonmetric cranial traits and an increase in the level of their fluctuating asymmetry in young females, which is indicative of epigenetic rearrangements in populations living in a radioactive environment.

The Settlement of Patagonia: A Matrix Correlation Study

Matrix correlation represents an innovative methodology to evaluate the explanatory power of several hypotheses by measuring their correspondence with observed morphological variation. In this paper, we view the origins of Patagonians from a matrix correlation approach. Personal and published data on nonmetric cranial traits were used to estimate a biological distance matrix involving five major groups from Patagonia and two from the northwest and northeast regions of Argentina. To evaluate correspondence with other important factors, we used a geographic distance matrix and four design matrices, representing several patterns of settlement and differentiation. Biological distance was found to be strongly associated with spatial separation; the correlation between geography and nonmetric cranial distances was highly significant. When geographic distance is held constant, correlation between a model representing high levels of heterogeneity between the samples and morphological (nonmetric) variation becomes highly significant.