Testing assumptions of the Gilbert and Gill method for assessing ancestry using the femur subtrochanteric shape

In 1990, Gilbert and Gill proposed a simple metric technique using femoral subtrochanteric anteroposterior and mediolateral diaphyseal diameters for discriminating between Native American and American Black and White femora in medicolegal and bioarchaeological contexts. However, there are several inherent assumptions in the method that may affect its validity. The assumptions include minimal sexual dimorphism, temporal and geographical homogeneity within populations, and that differences between populations in femoral subtrochanteric size and shape are primarily due to genetic variation. In this study, these assumptions are tested using femora from seven populations (African, American Black, American White, Australian, Native American, Hispanic, and Polynesian). The results indicate that sexual dimorphism and geographical and temporal heterogeneity in proximal femur diaphyseal shape within Native Americans are not great enough to significantly affect the validity of the Gilbert and Gill method (GGM). Variation between populations is most likely due to combined genetic and environmental factors, but differences in proximal femur shape between Native Americans and American Blacks/Whites are sufficient to allow accurate discrimination between these groups. Caution, however, must be taken during investigations where populations other than Native Americans or American Blacks/Whites are present, and therefore, the GGM may have limited forensic anthropological application in many parts of the world.     

Demography And Disease Patterns In A Protohistoric Plains Group: A Study ofthe Mobridge Site (39WW1)

Abstract

Epidemic disease has often been cited as the major factor causing historic depopulation of Native American groups. Because a range of infectious diseases introduced by Europeans struck different tribes at different times, the effects of these diseases or the outbreak of epidemics were not uniform for all groups. The Arikara of the American Plains wereamong the last North American Indian groups to experience direct contact with Europeans. However, indirect contact with introduced infectious diseases may have reduced these Plains protohistoric groups prior to established relations with Europeans. Historic depopulation of the Arikara and a demographic study of the skeletal remains from the Mobridge site (39WW1 l are the focus of this case study of the protohistoric population dynamics of a Native American group. Disease patterns are used in the demographic analysis to aid in the interpretation of observed mortality patterns. Evaluation of the skeletal remains from the Mobridge Site includes life table reconstruction and differential diagnosis of skeletal pathology complexes. Results of these analyses show that certain underlying disease processes evident skeletally correspond to deviations in the age distribution. Thus; the protohistoric mortality patterns of Mobridge appear to reflect the early stages of impact from introduced diseases.     

Craniometric Variation In The Northern And Central Plains

Abstract

Cranial measurements of 13 male and 12 female samples from the Central and Northern Plains region were subjected to canonical analysis. The samples include historic or protohistoric crania that can be ascribed to the Arikara, Mandan, Pawnee, Ponca and Omaha tribes. In addition, two samples belong to the archaeologically defined St. Helena Focus. Both sexes yielded five significant canonical variates, although only four were readily interpretable. The first canonical variate is clearly a Siouan-Caddoan discriminator and reflects variation in cranial vault height. St. Helena sites associate with the Arikara on this axis, supporting previous craniometric analyses which suggest a relationship between these two groups. Subsequent canonical variates deal with more particular aspects of craniometric variation among groups, but are still interpretable in historic or evolutionary terms. The classificatory analysis shows that the Arikara sites are closely related. A major exception to this is the Sully site, which frequently misclassifies with non-Arikara groups. This suggests that the Sully crania have little collective reality; and that there may be non-Arikara components represented at the Sully Site.     

Race and Ethnic Differences in Religious Involvement: African Americans, Caribbean Blacks and Non-Hispanic Whites

This study examined differences in religious participation and spirituality among African Americans, Caribbean Blacks (Black Caribbeans) and non-Hispanic Whites. Data are taken from the National Survey of American Life, a nationally representative study of African Americans, Black Caribbeans and non-Hispanic Whites. Selected measures of organizational, nonorganizational and subjective religious participation were examined. African American and Caribbean Blacks were largely similar in their reports of religious involvement; both groups generally indicated higher levels of religious participation than non-Hispanic Whites. African Americans were more likely than Black Caribbeans to be official members of their places of worship, engage in activities (choirs, church clubs) at their place of worship and request prayer from others. Black Caribbeans reported reading religious materials more frequently than African Americans. The discussion notes the importance of examining ethnic differences within the black American population of the United States.     

Microsatellites uncover extraordinary diversity in native American land races and wild populations of cultivated sunflower

The contemporary oilseed sunflower (Helianthus annuus L.) gene pool is a product of multiple breeding and domestication bottlenecks. Despite substantial phenotypic diversity, modest differences in molecular genetic diversity have been uncovered in anciently and recently domesticated sunflowers. The paucity of molecular marker polymorphisms in early analyses led to the hypothesis of a single domestication origin. Phylogenetic analyses were performed on 47 domesticated and wild germplasm accessions using 122 microsatellite loci distributed throughout the sunflower genome. Extraordinary allelic diversity was found in the Native American land races and wild populations, and progressively less allelic diversity was found in germplasm produced by successive cycles of domestication and breeding. Of 1,341 microsatellite alleles, 489 were unique to land races, exotic domesticates and wild populations, whereas only 15 were unique to elite inbred lines. The number of taxon-specific alleles was 35-fold greater among wild populations (26.27) than elite inbred lines (0.75). Microsatellite genotyping uncovered the possibility of multiple domestication origins. Land races domesticated by Native Americans of the southwestern US (Hopi and Havasupai) formed a clade independent of land races domesticated by Native Americans of the Great Plains and eastern US (Arikara and Seneca). Predictably, domestication and breeding have ratcheted genetic diversity down in sunflower. The contemporary oilseed sunflower gene pool, while not imperiled, could profit from an infusion of novel alleles from the reservoir of latent genetic diversity present in wild populations and Native American land races.     

The estimation of sex on the basis of the talus and calcaneus

The present report records and describes sexual dimorphism of the talus and calcaneus in American Blacks and Whites from the Terry Collection housed in the Smithsonian Institution, Washington, D.C. The greater amount of sexual dimorphism was observed in the talus, where 81 percent of the study sample could be accurately sexed. Four discriminant functions based on measurements from the talus and/or the calcaneus allowed sexing 79 to 89% of the study sample accurately. The techniques developed were then applied to two North American Indian samples, and sex of the individuals in these samples was assessed with the same degree of accuracy.     

Variation in the convexity of the human maxillary incisor labial surface

Labial surface convexity of the maxillary central incisors (ILC) is classified with a new five grade ranked scale. More than 2,000 individuals representing 20 worldwide populations were studied. Principle findings are 1) sexual dimorphism is not significant, 2) antimere asymmetry is moderate, 3) labial convexity is negatively associated (r = ?0.48) with labial surface double-shovelling, and 4) significant differences occur between several populations. Convexity is most marked in African and Asiatic Indian populations, particularly Bushmen. Europeans have intermediate degrees of convexity, and American Indians the least; Eskimos have the highest amount of convexity among Native Americans. Pacific Islanders are intermediate; Melanesians show the strongest expression of incisor labial convexity in the Pacific.     

Skeletal growth of the protohistoric Arikara.

The longitudinal growth of the long bones and growth in breadth of the ilium are assessed for a population of protohistoric Arikara Indians from South Dakota through the correlation of skeletal measurements with estimates of chronological age at death. Comparison of the Arikara growth data with those from other Indian samples (Indian Knoll and Late Woodland, Illinois) reveals similar rates of bone growth, when compensation is made for methodological variation. As predicted from documented variation in adult statures, the Indian samples indicate slower growth rates than those of Whites but faster than those of Eskimos.     

Differential sexual dimorphism in bone diameters of subjects of European and African ancestry

The 1,589 low-income adult subjects of primarily African ancestry (American Negroes or “Blacks”) showed systematically less sexual dimorphism in total subperiosteal area (TA), medullary area (MA) and cortical area (CA) than did 4,379 low-income adult subjects of European derivation (“Whites”). These systematic findings have implications both to the sexing of skeletal remains from diverse populations and to an understanding of population divergences in bone remodeling.     

Craniometric Relationships of Plains Populations: Historical and Evolutionary Implications

Abstract

Large skeletal samples from cemeteries in the Northern Plains near Mobridge, South Dakota have made possible the accurate determination of craniometric relationships between populations ancestoral to the historic Arikara. There is considerable change throughout the approximately 200 years represented, due primarily to gene flow from adjacent Siouan speaking groups. Arikara crania from the Northern Plains are seen to be morphologically similar to earlier crania further south, in particular St. Helena materials in northeastern Nebraska. This offers Support for the archaeological hypothesis that Coalescent Tradition cultures grew out of the Central Plains Tradition. Early crania from the Northern Plains are markedly different from those in the Central Plains and more similar to historic Mandan. The craniometric evidence argues for biological continuity rather than replacement in the Plains area.     

Big-bodied males help us recognize that females have big pelves

Schultz ([1949] Am. J. Phys. Anthropol. 7:401-424) presented a conundrum: among primates, sexual dimorphism of the pelvis is a developmental adjunct to dimorphism in other aspects of the body, albeit in the converse direction. Among species in which males are larger than females in body size, females are larger than males in some pelvic dimensions; species with little sexual dimorphism in nonpelvic size show little pelvic dimorphism. Obstetrical difficulty does not explain this relationship. The present study addresses this issue, evaluating the relationship between pelvic and femoral sexual dimorphism in 12 anthropoid species. The hypothesis is that species in which males are significantly larger than females in femoral size will have a higher incidence, magnitude, and variability of pelvic sexual dimorphism, with females having relatively larger pelves than males, compared with species monomorphic in femoral size. The results are consistent with the hypothesis. The proposed explanation is that the default pelvic anatomy in adulthood is that of the female; testosterone redirects growth from the default type to that of the male by differentially enhancing and repressing growth among the pelvic dimensions. Testosterone also influences sexual dimorphism of the femur. The magnitude of the pelvic response to testosterone is greater in species that are sexually dimorphic in the femur than in those that are monomorphic.     

Sexual dimorphism in human cranial trait scores: Effects of population,age, and body size

Sex estimation from the skull is commonly performed by physical and forensic anthropologists using a five‐trait scoring system developed by Walker. Despite the popularity of this method, validation studies evaluating its accuracy across a variety of samples are lacking. Furthermore, it remains unclear what other intrinsic or extrinsic variables are related to the expression of these traits. In this study, cranial trait scores and postcranial measurements were collected from four diverse population groups (U.S. Whites, U.S. Blacks, medieval Nubians, and Arikara Native Americans) following Walker's protocols (total n = 499). Univariate and multivariate analyses were utilized to evaluate the accuracy of these traits in sex estimation, and to test for the effects of population, age, and body size on trait expressions. Results revealed significant effects of population on all trait scores. Sample‐specific correct sex classification rates ranged from 74% to 94%, with an overall accuracy of 85% for the pooled sample. Classification performance varied among the traits (best for glabella and mastoid scores and worst for nuchal scores). Furthermore, correlations between traits were weak or nonsignificant, suggesting that different factors may influence individual traits. Some traits displayed correlations with age and/or postcranial size that were significant but weak, and within‐population analyses did not reveal any consistent relationships between these traits across all groups. These results indicate that neither age nor body size plays a large role in trait expression, and thus does not need to be incorporated into sex estimation methods. Am J Phys Anthropol 154:259–269, 2014. © 2014 Wiley Periodicals, Inc.     

Fourier analysis of acetabular shape in native American Arikara populations before and after acquisition of horses

The goal of this study was to identify changes in acetabular morphology associated with the use of horses by Native Americans. Previous studies reported "elongate" acetabula in horseback-riding members of the Omaha and Ponca populations. Such a difference in acetabular shape is a potentially useful osteological marker of habitual horseback riding. This report compares acetabula of adult males from two Native American Arikara populations known to have differed substantially in their use of horses. Population samples were from separate sites in South Dakota: Larson (nonriding) and Leavenworth (riding). Outlines of acetabular rims were digitized and analyzed, using a simplified 12-point Fourier analysis. A Fourier series with six terms accurately described acetabular shape. Significant differences (P<0.10) between riding and nonriding populations were observed in two Fourier coefficients. Acetabula of riding Arikara were found to have smaller B(4) coefficients (P = 0. 061) and more positive B(2) coefficients (P = 0.080), indicating expanded anterior-superior borders relative to acetabula of non-riding Arikara.     

Anterior femoral curvature: Its probable basis and utility as a criterion of racial assessment

Stewart ('62) and Walensky ('65) indicated that while the metrical expression of anterior femoral curvature alone will not always differentiate between Whites, American Negroes, and North American Indians, it was very useful as a racial criterion in combination with observed traits such as torsion, pilastry, and cross-sectional shape. Seven additional North American Indian groups reported here, representing both pre-Columbian and post-contact times, upheld the observation that anterior femoral curvature is a useful feature of racial assessment for Negroes, Whites and North American Indians. However, two South American groups studied (Ecuador and Peru) were only slightly more curved than American Negroes, and were less curved than Whites and North American Indians. The metrical expression of anterior femoral curvature therefore is not a useful feature of racial assessment for separating these two South American Indian groups from Whites and American Negroes. Femora of American Negro and White individuals with low ponderal indices were found to be less bowed than the norms for their race; individuals with high ponderal indices were more bowed than the norm for their race. The assumed genetic basis for expression of anterior femoral curvature suggested by Stewart ('62) and Walensky ('65) seems to be a feature of human plastic response to body weight rather than to temporal, clinal, postural or equestrian influences.     

Osteometry at muscle origin and insertion in sex determination

Multivariate statistical analyses were performed on 22 size measurements of the humerus from five sample populations: Sudanese Nubians, Arikara, Pecos Pueblos, American blacks, and American whites. The effects of muscle use ("occupational" differences) on identification of sex in this long bone are examined, particularly at points of muscle origins and insertions. The ramifications of the results of this research on sexual dimorphism studies of other bones are discussed.     

Divergence in Male and Female Manipulative Behaviors with the Intensification of Metallurgy in Central Europe

Humeral morphology has been shown to reflect, in part, habitual manipulative behaviors in humans. Among Central European agricultural populations, long-term social change, increasing task specialization, and technological innovation all had the potential to impact patterns of habitual activity and upper limb asymmetry. However, systematic temporal change in the skeletal morphology of agricultural populations in this region has not been well-characterized. This study investigates diachronic patterns in humeral biomechanical properties and lengths among 174 adult Central European agriculturalists through the first ∼5400 years of farming in the region. Greater asymmetry in biomechanical properties was expected to accompany the introduction of metallurgy, particularly in males, while upper limb loading patterns were expected to be more similar between the Bronze and Iron Ages. Results revealed a divergence in the lateralization of upper limb biomechanical properties by sex between the Early/Middle Neolithic and Early/Middle Bronze Age. Neolithic females had significantly more variable properties than males in both humeri, while Bronze Age female properties became homogeneous and very symmetrical relative to the right-biased lateralization of contemporaneous males. The Bronze Age to Iron Age transition was associated with morphological change among females, with a significant increase in right-biased asymmetry and a concomitant reduction in sexual dimorphism. Relative to biomechanical properties, humeral length variation and asymmetry were low though some significant sexual dimorphism and temporal change was found. It was among females that the lateralization of humeral biomechanical properties, and variation within them, changed most profoundly through time. This suggests that the introduction of the ard and plow, metallurgical innovation, task specialization, and socioeconomic change through ∼5400 years of agriculture impacted upper limb loading in Central European women to a greater extent than men.     

Microevolutionary change in Arikara Crania: a multivariate analysis

Measurements of human crania from five archaeological sites were subjected to canonical analysis. The five sites form a temporal sequence, ranging from prehistoric (ca. 1600 A.D.) to late historic (1830 A.D.), and belonging archaeologically to the Coalescent Tradition, which in South Dakota encompasses the historic Arikara Indians and their prehistoric ancestors. One canonical variate in each sex arranges the sites in their appropriate temporal sequence, presumably reflecting systematic microevolutionary change. The hypothesis that the morphological change resulted from gene flow from either White or Mandan Indian sources was tested using a two-group discriminate function. The function is found to effectively discriminate a Mandan sample and prehistoric Arikara, but becomes progressively less effective on the historic Arikara crania. This would suggest that Mandan gene flow into Arikara populations is responsible for the observed temporal variation. A similar analysis using British White crania suggests the possibility of slight White influence, but the effect is minimal compared to Mandan.     

Genetic relationships among Native American maize accessions of the Great Plains assessed by RAPDs

Genetic variation among 15 accessions of Native American maize from the Great Plains was investigated using random amplified polymorphic DNA (RAPD). RAPDs revealed very high levels of polymorphism among accessions. Banding patterns ranged in percentage polymorphism from 46.7% to 86.2% with an overall mean of 70.7% for the primers analyzed. The construction of genetic relationships using cluster analysis and principal coordinates analysis revealed that RAPDs are successful in confirming hypothesized relationships and in identifying misclassified specimens. Furthermore, the phenogram fails to reveal a strong correspondence between genetic relationships and the geographical position of Native Americans prior to contact. This provides support for the hypothesis that multiple introductions of maize into the Great Plains via trade may have resulted in the great morphological variation found among accessions in the region. Based on these data, it is unlikely that a separate Great Plains race of maize can be distinguished. In general, we conclude that RAPDs are potentially very useful in organizing seed collections and understanding intraspecific genetic differentiation. Received: 10 March 1999 / Accepted: 25 March 1999     

An 'epidemic' model of adolescent sexual intercourse: applications to national survey data

This paper applies models of the onset of adolescent sexual intercourse using national data from Denmark and the USA. The model gave excellent fits to data on Danish Whites and a good fit to American Whites, but the model-fits for American Blacks and Hispanics were not as good. The weakness of the latter model fits may reflect either real processes that the model does not capture or problems in the reliability of adolescent sexuality data.     

Effect of mobility on femur midshaft external shape and robusticity

This study investigates differences in femur midshaft shape, robusticity, and sexual dimorphism derived from external measurements between a broad range of prehistoric and historic North American populations with different subsistence strategies and inferred levels of mobility. The sample was divided into six groups to test whether observed femur midshaft variables follow the patterns predicted based on archaeologically and historically determined subsistence and mobility data. The results suggest significant variation in femur midshaft shape and robusticity in all populations, and that inferred mobility levels do not correspond consistently with femur midshaft structure in either males or females. Results do, however, support the prediction that sexual dimorphism is generally greater in more mobile populations.