Sex differences in radioulnar contrasts of the finger ridge counts across 21 human population samples.

Aim: The aim of the present study was to demonstrate the existence of uniform sexual dimorphism in some radioulnar contrasts between different finger ridge counts within the same hand in a large set of populations, thus confirming the universal nature of this dimorphism in humans.Subjects and methods: We analysed individual finger ridge counts (10 values on each hand) of both hands from archival sources (mainly the Brehme-Jantz database). In total, these included 4412 adults from 21 population samples covering all permanently inhabited continents and encompassing very different and geographically distant human populations. We calculated the contrasts (differences) of all pairs of ridge counts (45 per hand) and used diverse methods to assess the direction and degree of dimorphism of them across all population samples.Results: The highest sexual dimorphism was observed for nine contrasts involving the ridge count of the dermatoglyphic pattern on the radial side of the second finger of the right hand (R2r). Among these contrasts, we then found four that had the same direction of dimorphism in all 21 populations. The most dimorphic was the contrast R1rR2r - the difference between the ridge count of the radial side of the thumb and the radial side of the index finger.Discussion: Thus, these dermatoglyphic traits can be further investigated as potential markers of prenatal sex differentiation from ca. 10th week of intrauterine development. However, it will be useful to address the detailed factors and mechanisms for differences in the degree of dimorphism of these traits in different populations.

Limb bone allometry in modern Euro-Americans.

OBJECTIVES: The pattern of static and secular allometry was examined in a time series of limb bone lengths from individuals with birth years ranging from 1840 to 1989. The main hypothesis investigated was that secular changes in limb proportions, as seen in changes in the brachial and crural indices, can be explained by allometric responses to increasing size. MATERIALS AND METHODS: Maximum lengths of humerus, radius, femur, and tibia were obtained from 19th and 20th centuries identified skeletons. Allometry was investigated on two levels, static and secular. Static allometry was defined as average allometry within 20-year birth cohorts, and secular allometry as allometry among birth year cohorts. Allometry was assessed by extracting eigenvectors from covariance matrices of log transformed variables. Departures from allometry were examined using shape variables, and principal components of minor axes. RESULTS: Static covariance matrices were homogeneous. Eigenvectors extracted from the secular covariance matrix showed important departures from static allometry, particularly a much stronger negative allometry of the humerus and a stronger positive allometry of the tibia. Shape analysis showed that relative humerus length decreased significantly over the time period examined and relative tibia length increased. The last principal component, which combined aspects of the brachial and crural index, showed the highest variation among birth year cohorts. DISCUSSION: The results demonstrate that the secular changes in limb proportions cannot be explained by allometric responses to increasing size alone. The majority of variation among birth cohorts is found on the last PC and that suggests that canalized development has been disrupted by the unique environment in which modern Americans now live.

Secular change in craniofacial morphology.

Five craniofacial variables (glabella-occipital length, basion-bregma height, maximum cranial breadth, nasion-prosthion height, and bizygomatic breadth) were used to examine secular change in morphology from the mid-19(th) century to the 1970s. The 19(th) century data were obtained from the Terry and Hamann-Todd anatomical collections, and the 20(th) century data were obtained from the forensic anthropology databank. Data were available for Blacks and Whites of both sexes. Secular change was evaluated by regressing cranial variables on year of birth. Two analyses were conducted, one using the original variables and one using size and shape. Size is defined as the geometric mean of the cranial variables, and shape is the ratio of each variable to size. The results show remarkable changes in the size and shape of the cranial vault. Vault height increases in all groups in both absolute and relative terms. The vault also becomes longer and narrower, but these changes are less pronounced. Face changes are less than the vault changes, but to the extent that they occur, the face becomes narrower and higher. Overall cranial vault size has increased, but shape changes are greater than size changes. The magnitude of secular change in vault height exceeds that for long bones over a comparable time period, but follows a similar course, which suggests that vault height and bone length respond to the same forces. Changes in vault dimensions must occur by early childhood because of the early development of the vault. Am. J. Hum. Biol. 12:327-338, 2000. Copyright 2000 Wiley-Liss, Inc.

Modification of the Trotter and Gleser female stature estimation formulae.

Stature-estimation formulae in common use are those of Trotter and Gleser. Their formulae for females are based on Terry collection skeletons. These skeletons are from people who died in the early 1990s. Because there has been considerable change in body size since then, it is possible that the Trotter and Gleser formulae are inappropriate for modern forensic-science application. The Trotter and Gleser female formulae are tested using data from the Forensic Data Bank at the University of Tennessee. For whites, the femur and tibia yield stature estimates differing from one another by about 3 cm. Using femur and tibia lengths from modern forensic cases and modern height data from anthropometric surveys, new regression intercepts are calculated for Trotter and Gleser's female formulae. The new intercepts improve the performance of the formulae on modern individuals. The Trotter and Gleser formulae for black females require no adjustment. Both blacks and whites have experienced a secular increase in bone length, but whites have experienced a change in proportions as well.

Cranial change in Americans: 1850-1975.

This paper examines the pattern and magnitude of craniofacial change in American blacks and whites over the past 125 years. Standard metric data from 885 crania were used to document the changes from 1850 to 1975. Data from 19th century crania were primarily from anatomical collections, and 20th century data were available from the forensic anthropology data bank. Canonical correlation was used to obtain a linear function of cranial variables that correlates maximally with year of birth. Canonical correlations of year of birth with the linear function of cranial measurements ranged from 0.55 to 0.71, demonstrating that cranial morphology is strongly dependent on year of birth. During the 125 years under consideration, cranial vaults have become markedly higher, somewhat narrower, with narrower faces. The changes in cranial morphology are probably in large part due to changes in growth at the cranial base due to improved environmental conditions. The changes are likely a combination of phenotypic plasticity and genetic changes over this period.

Estimation of stature from metacarpal lengths.

Formulae for the estimation of stature from metacarpal lengths are presented. Two samples of metacarpal specimens were employed in the analysis: one of 212 individuals from the Terry Collection, and one of 55 modern males, all of whom had measured statures. One measurement, the midline length, was taken on each metacarpal. Stature was regressed on the basis of the metacarpal length to derive equations for the Terry Collection individuals. Comparisons between the Terry Collection males and the modern sample showed the latter to have longer metacarpals and greater statures. The Terry equations were tested using the modern male sample. In spite of the differences noted, the Terry equations perform acceptably on modern individuals. The performance was slightly better for whites than for blacks. Since the female equations were not tested, they should be employed with greater caution.

Allometric secular change in the long bones from the 1800s to the present.

Allometric secular changes in the six long limb bones for White and Black males from the mid 1800s to the present are examined. Long bone lengths are available from the Terry collection and WWII casualties. We conducted two types of analysis to reveal secular changes. First, allometry scaling coefficients were derived by regressing log bone length onto log stature. These showed that the femur, tibia and fibula were positively allometric with stature, while the humerus, radius and ulna were isometric. The lower limb bones were more positively allometric in the WWII sample than in the Terry sample. Second, secular changes in length of femur and tibia and in the tibia/femur ratio were evaluated, using modern forensic cases in addition to the Terry and WWII samples. This analysis shows that secular increase in lower limb bone length is accompanied by relatively longer tibiae. Secular changes in proportion may render stature formulae based on nineteenth century samples, such as the Terry collection, inappropriate for modern forensic cases. The positive allometry of the lower limb bones argues against using simple femur/stature ratio, which assumes constant proportionality, as an alternative to regression equations.

Stature estimation from fragmentary femora: a revision of the Steele method.

The skeletal remains presented to forensic anthropologists are often fragmentary. Previously described methods of estimating stature from segments of long bones have not proved satisfactory because of the difficulty involved in identifying the precise anatomical landmarks by which they are defined. This study represents an assessment of the feasibility of stature estimation from fragmentary femora. A sample of 200 males and females, blacks and whites (total sample = 800), was obtained from the Terry Collection. New regression equations for the estimation of maximum femur length and stature from three well-defined and easy-to-measure segments of the femur are presented. This technique represents an improvement over methods currently in use for estimating stature from femur fragments; the location of the anatomical landmarks and the accuracy of the prediction are enhanced. The applicability of these formulae to a modern forensic sample is addressed with regard to secular trends in stature increase and changes in body segment proportions.

The measure and mismeasure of the tibia: implications for stature estimation.

Trotter and Gleser's stature estimation formulae, based on skeletons of the Terry collection and on WWII casualties, have been widely used in forensic work. Our work with the Terry and WWII data yielded tibia lengths too short compared to other data sets. Using Trotter's original measurements, we discovered that she consistently mismeasured the tibia. Contrary to standard practice and her own definitions, she omitted the malleolus from the measurement. Trotter's measurements of the tibia are 10 to 12 mm shorter than they should have been, resulting in stature estimations averaging 2.5 to 3.0 cm too great when the formulae are used with properly measured tibia. We also examined tibia lengths of Korean War casualties, which were measured by technicians rather than by Trotter. Korean tibia measurements are also too short, but by a smaller amount than Terry and WWII. Since the Korean tibia are unavailable for restudy, it is unclear how they were measured. Estimation of stature from Trotter and Gleser's tibia formulae is to be avoided if possible. If necessary, the 1952 formulae could be used with tibia measured in the same manner that Trotter measured, excluding the malleolus.

Cranial thickness in American females and males.

To date, numerous studies have examined the range of cranial thickness variation in modern humans. The purpose of this investigation is to present a new method that would be easier to replicate, and to examine sex and age variation in cranial thickness in a white sample. The method consists of excising four cranial segments from the frontal and parietal regions. The sample consists of 165 specimens collected at autopsy and 15 calvarial specimens. An increase in cranial thickness with age was observed. The results suggest that cranial thickness is not sexually dimorphic outside the onset of hyperostosis frontalis interna (HFI).

Maxillary suture obliteration: a visual method for estimating skeletal age.

The purpose of this study was to develop a method of estimating the age of an individual based on obliteration of the four maxillary (palatal) sutures. A sample of 186 individuals of known age, race, and sex were examined. It was found that males of both races (black and white) exhibit more suture obliteration than females at the same age. During the early adult years, maxillary suture obliteration progresses at nearly the same rate in both sexes; however, the age of old individuals may be greatly overestimated using this method. Although this method cannot be used for exact estimates of individual age, it is valuable in establishing the age range, sorting commingled remains, and estimating skeletal age when only the maxilla is present.

Variation among European populations in summary finger ridge-count variables.

The magnitude of ridge-count variation and its spatial and linguistic patterning was examined using 82 male and 75 female samples from Europe. Variables were summary measures: sum of radial counts (radial) sum of ulnar counts (ulnar) and sum of larger counts (total ridge-count or TRC). Dermatoglyphic parameters were compared with those derived from classic nuclear gene markers. Fst values computed from ridge-counts range between 0.016 and 0.025, relatively high when compared to classical genetic polymorphism. Ridge-count distances show significant correlation with geographic distances but not with linguistic distances. Ridge-count distances show even higher correlation with blood marker distances, suggesting that, like blood polymorphisms, ridge-counts were strongly influenced by demic expansion of Neolithic farmers. The most differentiated populations in Europe are those of the North Atlantic and North Sea region, especially the Orcadians and Faroe Islanders. Certain Finnic speakers such as Lapps and Udmurts are also strongly differentiated. These same populations are frequent outliers in genetic analyses.

Franz Boas and Native American biological variability.

The contributions to physical anthropology with which Franz Boas is usually credited are in the areas of growth, plasticity of head and body form, and biometric genetics. Such a listing of Boas's contributions overlooks the tremendous amount of research he did with biological variability of Native American populations. The rediscovery of his anthropometric data documents the tremendous investment in time, money, and effort Boas devoted to the topic and provides the opportunity to rediscover his insights into a subject that is of continuing interest. The design of his massive anthropometric survey of native North Americans reveals a concern for population analyses and a rejection of the typological framework of the time. If Boas's ideas had been adopted at the turn of the century, the development of physical anthropology in America might have been much different.

Sex and race differences in finger ridge-count correlations.

Correlations between ridge-counts on the ten fingers were compared by race and sex in 11 samples representing Negroes and Caucasians: five from subsaharan Africa, one American Black, three European, one American White and one from India. The samples of European ancestry showed no consistent sex difference in mean correlation, although female American Whites significantly exceeded males. In three of the six Negro samples and in the Parsis of India males showed significantly higher average correlations than females. The pattern of sex and race differences suggests that the sex chromosomes, particularly the Y chromosome, play a role in dermal ridge development.

The relation between total finger ridge-count and variability of counts from finger: genetic implications of racial variation.

The measure of ridge-count diversity, S/square root 10, was computed for a sample of American Whites, American Blacks and African Blacks, and the regression of S/square root 10 on total ridge-count was determined for each group. The shapes of the regression lines differed considerably. The American White curve was very similar to that obtained by Holt in an English sample, while the two Negro curves generally showed lower lower S/square root 10 values for ridge-counts over 80. The American Negro curve was found to behave like a mixture of the White and African Negro curve to a degree approximating to the fraction of White genes in their gene pool. Holt's parent-child data are used to construct a simple test of the hypothesis that that S/square root 10 reflects zygosity in total ridge-count genotypes. The preliminary results support this hypothesis.

Population variation in asymmetry and diversity from finger to finger for digital ridge-count.

Population variation in ridge-count asymmetry and diversity from finger to finger has received scant attention in dermatoglyphic studies. Asymmetry, in particular, has generally been attributed to environmental effects operating during the formation of dermal ridges. Examination of samples from several groups of diverse racial background revealed the existence of considerable population variation with respect to finger ridge-count asymmetry and diversity from finger to finger. Patterning along population lines suggests a genetic rather than environmental basis for such variation. The genetic mechanisms responsible for ridge-counts may also mediate asymmetry and diversity, or the degree of developmental stabiltiy in different populations may itself be under genetic control.

Temporal changes in limb proportionality among skeletal samples of Arikara Indians.

Relative lengths of the radius, humerus, tibia and femur were examined in children obtained from ten archaeological sites in South Dakota. The sites range in time from about AD 1600 to 1830, and all are attributed to the Arikara Indians or their immediate ancestors. Changes in long bone proportions were examined by regressing the log of each bone on the log of the sum of all four bones. The regression coefficient which results represents the relative rate of change of the bone in relation to the sum of all bones. Proximal bones were found to increase faster than distal bones in both upper and lower limbs, and lower limbs increase faster than upper ones. The regression coefficients for tibia and femur exhibit significant heterogeneity over the ten sites, indicating that the pattern of proportional changes with growth is not the same for all groups. Furthermore, variation in regression coefficients among sites is temporally patterned, early sites being characterized by relatively longer femora and shorter tibiae, while the reverse is the case for the late sites. The temporal nature of relative femur-tibia lengths suggests that this is an adaptive change possibly with both genetic and nongenetic components.

Formation of the permanent dentition in Arikara Indians: timing differences that affect dental age assessments.

This report concerns one problem encountered with application of American white dental formation standards to age assessment of sub-adults of archaeological context. Dental ages for eight mandibular permanent teeth and maxillary central and lateral incisors of Arikara Indian immature skeletons were determined according to degree of crown or root mineralization. Ages assigned to the various teeth of the same individual were compared. They showed similarities as well as patterned differences. First premolar, second premolar, and mandibular incisor ages closely approximated one another. In relation to this complex, dental ages for maxillary incisors and mandibular second molars were older by 0.5 to 1.1 years. Developmental ages assigned to individuals on the basis of third molars showed relative advancement by more than 2 years. The systematic occurrence of these observations reflects more than just individual variability; it shows the presence of population differences in tooth-formation timing. Timing differences complicate assessment of dental ages needed for growth or demographic studies.

Long bone growth among Arikara skeletal populations.

Long bone growth variation among skeletal samples had had limited application to ecological studies of archaeological groups, in spite of its well-known sensitivity to health and nutritional status. In this study we examine long bone growth variation among ten samples of Arikara skeletal groups, all located in the Middle Missouri subarea of South Dakota and ranging in time from A.D. 1600 to 1832. The samples are analyzed by variant, an archaeological taxonomic unit below Tradition. Children's long bones between about 0.5 and 11.9 years of age were analyzed by means of regression using the model, bone length = b0 + b1 (age) + b2 (log10 age). The three variants, Extended Coalescent, Postcontact Coalescent, and Disorganized Coalescent, differ from one another with regard to health and nutritional status. Extended Coalescent groups probably experienced periods of undernutrition due to unfavorable climatic conditions prevailing at the time. Postcontact Coalescent groups experienced more favorable health and nutrition due to improved climatic conditions and introduction of the horse. Disorganized Coalescent groups were exposed to undernutrition and high levels of morbidity, due to introduction of epidemic diseases, depopulation, and intertribal conflict. Analysis of slopes shows significant heterogeneity among variants for humerus, radius, and tibia, but not femur. In general, the Postcontact Coalescent is characterized by slighter greater rates of increase with age and longer bone lengths for each age than is Extended Coalescent. Disorganized Coalescent exhibits lower rates of increase, particularly in later childhood, with shorter bone lengths in late childhood.(ABSTRACT TRUNCATED AT 250 WORDS)

Population structure of Algonquian speakers.

Speakers of Algonquian languages are widely dispersed geographically but are homogeneous linguistically. We examine anthropometric differentiation among Algonquian-speaking populations distributed from New Brunswick to Montana. Head and face measurements and body measurements were analyzed separately in an attempt to address the effect of phenotypic plasticity on relationships. The head and face and body dimensions yield somewhat different pictures of relationships. From the head and face data an east to west geographic pattern can be discerned. The principal feature of the body measurements is the distinctiveness of the Ojibwa located northwest of Lake Superior. The formal correlation between the two sets of measurements is low and not significant. Only the head and face dimensions correlate significantly with geographic distances. Language distances do not correlate with anthropometric distances. The set of populations is also more strongly differentiated with respect to body measurements than to head and face measurements. We interpret this as reflecting phenotypic plasticity and possibly greater interobserver variation.