Secular Changes in the Postcranial Skeleton of American Whites

Secular change in height has been extensively investigated, but size and shape of the postcranial skeleton much less so. The availability of large, documented collections of nineteenth- and twentieth-century skeletons makes it possible to examine changes in skeletal structure over the past 150 years. We examined secular changes in long bone lengths and proportions, their allometric relationship to stature, and cross- sectional properties of long bone shafts. Bone measurements and stature were organized into 10-year birth cohorts, ranging from 1840 to 1989. Variation among cohorts was tested by one-way ANOVA, and secular trend was examined visually by plotting mean measurements by birth decade. Allometry was examined by regressing log bone lengths onto log stature, using least squares regression. Allometry was also examined using the geometric mean of log bone lengths as the size variable. All bone lengths and stature showed positive secular change. Stature and the distal long bones showed the most pronounced changes. Proportions also changed, as revealed by the brachial and crural indices. Both indices increased, but the brachial index change was the most pronounced. Allometric relationships suggest that brachial index changes result from positive allometry of the radius and negative allometry of the humerus. Similar but less marked allometric relationships were found in the tibia and femur. Long bone shaft properties changed in the following ways: femur midshafts and tibia shafts at the nutrient foramen became more mediolaterally narrowed, and the femur became more mediolaterally thickened at the subtrochanteric level, approaching platymeria. All major long bones became more gracile. These remarkable changes in the postcranial skeleton are a response to the unparalleled changes in the environment in which modern Americans now live. Changes in growth resulting from plentiful and secure nutrition, reduced disease load, and marked reduction in bone loading from reduced activity levels are mainly responsible

Evaluating Nubian Population Structure from Cranial Nonmetric Traits: Gene Flow, Genetic Drift, and Population History of the Nubian Nile Valle

Paleolithic archaeological and skeletal remains from the Nile Valley have yielded a complex picture of life along the river. Sociocultural and sociopolitical events during this timeframe shaped population structure, while gene flow and genetic drift further developed it. In this paper, we take a population genetics approach to modeling Nubian biological relationships in an effort to describe how an accumulation of events formed Nubian population structure. A variety of Nubian samples were utilized, spanning the Mesolithic-Christian time periods, and geographically, from just above the first through the third cataracts. Population genetics statistics were employed to estimate and depict biological affinities (Mahalanobis D2 with a tetrachoric matrix, principal coordinates analysis, Fst, and Relethford Blangero residuals) and supplemented by spatial-temporal modeling (Mantel tests and PROTESTs). Variation is high amongst these groups, indicating an intricate pattern of relationships in their population history where similar levels of gene flow probably stemmed from extensive cultural contact with Egypt and other populations in a variety of contexts. Genetic drift is also apparent in some of these sites, which is consistent with social and political histories of these groups. Traditional modeling of spatial-temporal patterning was not successful, which may be attributed to the non-linear, loose clustering of Nubian groups by site. Collectively, the archaeological, biological, and environmental evidence support the ideas of multiple populations living in Lower Nubia during the Paleolithic, and/or a new population entering the area and shaping Nubian population structure

An Examination of the Differential Effects of the Modern Epidemiological Transition on Cranial Morphology in the United States and Portugal

This research examines the pattern of secular change in the cranial morphology of two populations experiencing the epidemiological transition associated with decreased mortality rates in children, followed by declines in infant mortality and subsequent increases in adult longevity. The two samples examined in this study come from US and Portuguese individuals. The epidemiological transition oc- curred at different times in the United States and Portugal, with Portugal entering into the transition later than the United States. The results of the study show that the US and Portuguese samples experienced significant changes in cranial morphology during the approximately 150 years under study. In all of the samples the cranial base morphology changes significantly over time. However, the pattern of change in the US and Portuguese samples varies in the other regions of the crania. The US samples exhibit significant changes associated with the posterior cranial fossa, which experiences the greatest growth during the fetal period and the first year of life. Conversely, in the Portuguese samples the region of the cranium that shows the greatest change is in the face and lateral cranial base, which experiences the greatest growth from three to nine years. This differential pattern may reflect differences in changing mortality patterns in the two countries. During the period under study the United States had already proceeded through the early stages of the epidemiological transition, and improvements in the juvenile mortality and juvenile growth had occurred previously. Subsequently, the United States experienced significant declines in infant mortality, and the regions of the crania that exhibit the greatest changes occur in area with maximum growth velocity under one year. However, Portugal entered into the epidemiological transition later than the United States and therefore the greatest changes in growth occurred during the juvenile period, which is reflected in the adult morphology in this group. This study demonstrates the utility of variation in growth patterns in different cranial regions to document changes in the demographic parameters in two different populations

Artifacts and Commingled Skeletal Remains from a Well on the Medical College of Virginia Campus: Appendices

This is a report prepared by Douglas W. Owsley and Karin Bruwelheide, Department of Anthropology, National Museum of Natural History, Smithsonian Institution in fulfillment of the Contract Agreement between the Smithsonian Institution. The objectives of this report included identification and documentation of the bones and artifacts recovered from the well, establishing the temporal context, and interpreting the relationship of the materials to the site’s use and history as an early medical school in the city of Richmond. This report has three main sections: a review of the archival history of the school as it related to the use of the well, a description of the artifact assemblage, and documentation of the human remains, including craniometric and postcraniometric analyses. Researchers with differing areas of expertise contributed to this report

Heredity, Environment, and Cranial Form: A Reanalysis of Boas's Immigrant Data

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65137/1/aa.2003.105.1.125.pd

The Remarkable Change in Euro-American Cranial Shape and Size

Secular changes in stature, weight, or other components of the body that can be obtained from historical records have been extensively studied. Cranial change has been central to anthropology for more than a century, but the focus has normally been on change measured in centuries or millennia. Cranial change measured in decades, normally considered to result from plastic response to the environment, has been less studied. This article reports on change in cranial vault dimensions in white Americans. Variables were glabello-occipital length (GOL), basion-bregma height (BBH), basion-nasion length (BNL), maximum cranial breadth (XCB), and biauricular breadth (AUB). Cranial size was calculated as the geometric mean of these variables, and shape dimensions were calculated as described by Darroch and Mosimann (1985). Cranial module and cranial capacity were also calculated. Samples consisted of 1,112 males and 668 females complete for those variables. Samples were organized into 10-year birth cohorts, with birth years ranging from 1820 to 1990. One-way ANOVA was used to test for variation among cohorts. The pattern of secular change was examined graphically and was compared with quality-of-life and environmental indicators, including stature, infant mortality, calories per person, and relative number of immigrants. All variables showed significant secular change, but BBH, XCB, and BNL responded most strongly. Over the past 170 years, crania became relatively higher, narrower, and larger with longer cranial bases. Both sexes changed, but female change was less pronounced than male change. The cranial variables tracked secular changes in stature, most prominently BNL. The highest correlation between a cranial variable and quality-of-life indicator was BBH and infant mortality. We are not able to identify specific causes of secular changes in cranial morphology. However, given that modern Americans have introduced themselves into a novel environment never before experienced by human populations, we consider it unlikely that it is pure plasticity. In addition to possible plastic responses, it is likely that selection, acting through the dramatic changes in infant mortality, is also involved

Finger Ridge-Counts and Inter-Finger Variability in Negroes and Whites

Finger ridge-counts and a measure of inter-finger variability (S/√10) were investigated in samples of Negroes and Whites. In general, Whites have higher ridge-counts than Negroes, but none of the differences is statistically significant. S/√10 provides a better and more realistic means of distinguish­ing between the two racial groups

Anthropometric Variation among the Sioux and the Assiniboine

Historically, the Assiniboine are thought to have split from the Yanktonai Sioux some time in the early 17th century, but this view has been challenged by some linguists, archeologists, and skeletal biologists. Our purpose here is to examine the population structure of the Sioux and the Assiniboine, as reflected in 6 head and 6 body anthropometric dimensions, and to investigate the hypothesis that the Assiniboine diverged relatively recently from the Yanktonai Sioux. For both males and females there is an overall significant division effect, and the FST value indicates a fair amount of differentiation among these closely related groups. The Assiniboine are clearly distinct from all 3 Sioux divisions. The Assiniboine also exhibit a higher within-group phenotypic variance than expected, indicating that their differentiation is due to time and gene flow from outside groups. Among the Sioux divisions the Santee and Yankton-Yanktonai are the most similar, especially in head and face dimensions. The results of this study do not support the historical account of Assiniboine origins. The high degree of differentiation between the Yanktonai and Assiniboine suggests a much more distant split between the Assiniboine and the Sioux than has been traditionally put forth