Principal-components analysis of Brazilian Indian anthropometric data

Analysis of nine characteristics on 1,205 males and 932 females from 12 tribes or groups of tribes indicated a poor relationship between morphology and language, as well as moderate agreement with the variability expected considering geography only. Two samples in the Xingu area studied during an interval of half a century (1897-1947) showed remarkable similarity. The conformity of the Caingang morphology with those of other tribes and the distinctiveness of the Xavante and Tenetehara has been amply confirmed.     

Variation among early North American crania

The limited morphometric work on early American crania to date has treated them as a single, temporally defined group. This paper addresses the question of whether there is significant variability among ancient American crania. A sample of 11 crania (Spirit Cave, Wizards Beach, Browns Valley, Pelican Rapids, Prospect, Wet Gravel male, Wet Gravel female, Medicine Crow, Turin, Lime Creek, and Swanson Lake) dating from the early to mid Holocene was available. Some have recent accelerator mass spectrometry (AMS) dates, while others are dated geologically or archaeologically. All are in excess of 4500 BP, and most are 7000 BP or older. Measurements follow the definitions of Howells [(1973) Cranial variation in man, Cambridge: Harvard University). Some crania are incomplete, but 22 measurements were common to all fossils. Cranial variation was examined by calculating the Mahalanobis distance between each pair of fossils, using a pooled within sample covariance matrix estimated from the data of Howells. The distance relationships among crania suggest the presence of at least three distinct groups: 1) a middle Archaic Plains group (Turin and Medicine Crow), 2) a Paleo/Early Archaic Great Lakes/Plains group (Browns Valley, Pelican Rapids, Lime Creek), and 3) a spatially and temporally heterogeneous group that includes the Great Basin/Pacific Coast (Spirit Cave, Wizards Beach, Prospect) and Nebraska (Wet Gravel specimens and Swanson Lake). These crania were also compared to Howells' worldwide recent sample, which was expanded by including six additional American Indian samples. None of the fossils, except for the Wet Gravel male, shows any particular affinity to recent Native Americans; their greatest similarities are with Europe, Polynesia, or East Asia. Several crania would be atypical in any recent population for which we have data. Browns Valley, Pelican Rapids, and Lime Creek are the most distinctive. They provide evidence for the presence of an early population that bears no similarity to the morphometric pattern of recent American Indians or even to crania of comparable date in other regions of the continent. The heterogeneity among early American crania makes it inadvisable to pool them for purposes of morphometric analysis. Whether this heterogeneity results from different early migrations or one highly differentiated population cannot be established from our data. Our results are inconsistent with hypotheses of an ancestor-descendent relationship between early and late Holocene American populations. They suggest that the pattern of cranial variation is of recent origin, at least in the Plains region.     

Variation within teosinte. III. numerical analysis of allozyme data

Principal components analysis of isozyme allele frequencies at 19 loci revealed 133 electrophoretic variants for 77 accessions of annual teosinte and 1 accession each of diploid and tetraploid perennial teosintes. The majority of alleles were found in low frequency, and many were distributed only in specific locations. Zea luxuriansand the annual Mexican teosintes appeared to be the most distantly related of all teosintes. Z. perennisand Z. diploperennisappeared distinct from each other and from all other teosintes. Teosintes of west Guatemala (Huehuetenango) did not appear especially closely related to Balsas teosintes. Several differences were apparent between Chalco and Central Plateau teosintes;however, these differences were not so extreme as those suggested by chromosome knob data. Nobogame teosintes appeared closely related to Chalco and Central Plateau teosintes. Isozyme data reveal teosinte to be a diverse source of germplasm.     

Multivariate analysis of anthropometric data and classifications of British Columbian natives

Anthropometric data collected in native populations of British Columbia in the late 19th century by Franz Boas were analyzed by two multivariate techniques. Multivariate analysis of variance was used to test physical classificatory units devised by Boas and an ad hoc classification based on local cultural units. Both were found to have some empirical validity. Mahalanobis' D (Mahalanobis, '30) was computed between pairs of local groups, for both sexes. From these a matrix of differences was prepared and diagrams drawn to illustrate phenetic relationships among samples. By this means one cluster of groups, Interior B.C. peoples, could be distinguished and other local samples appeared distinctly different from each other. It was concluded that in the absence of genealogical data by which to identify local populations, local cultural units are preferable to more inclusive units for making empirical comparisons and classifications.     

Genetic,acclimatizational and anthropometric factors in hand cooling among North and South Chinese

The left hands of unacclimatized North Chinese (N = 16) and South Chinese (N = 13) were exposed to 5°C water for 30 minutes followed by a 10 minute recovery period. Significant differences independent of body composition were found between the two samples on mean 30 minute temperature during immersion, time and temperature of the onset of initial CIVD (cold-induced vasodilation) at 0.01, 0.05 and 0.10 levels respectively. The result suggests the presence of a genetic component in the cold responses of Continental Asian populations and the possibility of the presence of a clinal distribution of cold response in Asia.     

Variation of anthropometric traits in normal newborns]

Variation of the set of anthropometric traits was studied in 302 normal singleton newborns (174 boys, 128 girls). Birth order has a significant effect on birth weight, body length and circumference of head and breast. The number of minor deviations from development per newborn (stigma) is negatively correlated with body weight and size. The number of stigma is significantly higher in a group of newborns deviated in normal body proportions. The index of fluctuating asymmetry is negatively correlated with body weight and size.     

The S-leut anthropometric traits: Genetic analysis

Genetic analyses were conducted on 51 anthropometric measurements and on four factors derived from them by factor analysis. These variables were obtained on 784 members of a religious isolate, the S-leut. Correlations were computed between relatives, and heritabilities were estimated using information on extended families. Longitudinal measurements generally exhibited the highest heritabilities. The test for fit of a major gene model was significant for 13 of the 55 variables, the circumferential and breadth measurements giving the strongest evidence for major gene control. In another approach to establishment of genetic control, linkage analysis was performed between the anthropometric variables and blood group and serum protein polymorphisms. Several traits showed some evidence for linkage but none achieved statistical significance.     

Genome size variation in North American minnows (Cyprinidae). II. Variation among 20 species

Genome sizes (nuclear DNA contents) from 200 individuals representing 20 species of North American cyprinid fishes (minnows) were examined spectrophotometrically. The distributions of DNA values of individuals within populations of the 20 species were essentially continuous and normal; the distribution of DNA values among species was continuous and overlapping. These observations suggest that changes in DNA quantity in cyprinids are small in amount, involve both gains and losses of DNA, and are cumulative and independent in effect. Significant heterogeneity in mean genome size occurs both between individuals within populations of species and among species. The former averages maximally around 6% of the cyprinid genome and is nearly the same as the amount of DNA theoretically needed for the entire cyprinid structural gene component. The majority of the DNA content variation among the 20 species is distributed above the level of individuals within populations. Comparisons of average genome size difference or distance between individuals drawn from different levels of taxonomic organization indicate that considerably greater divergence in genome size has occurred in the extremely speciose cyprinid genus Notropis as compared with other North American cyprinid genera. This may suggest that genome size change is concentrated in speciation episodes. Finally, no associations were found between interspecific variation in genome size and five life-history characters. This suggests that much of the variation in genome size within and among the 20 species may be phenotypically inconsequential.     

Age-related changes of the craniofacial skeleton: an anthropometric and histologic analysis.

With the development of increasingly sophisticated methods for the alteration of bony facial form consequent to age, it is imperative that the surgeon have a fundamental knowledge of the age-related changes the skeleton may undergo. To understand these changes better, a detailed anthropometric and histomorphic analysis of the craniofacial skeleton as a function of age was undertaken. The study consisted of a detailed craniometric analysis of 160 skulls selected randomly from a Caucasian population of skeletal remains totaling 1500 specimens. Additionally, a histologic analysis of the supraorbital ridge in a separate preserved cadaver population was performed. Although the results showed individual variation as expected, definite changes in craniofacial morphology were observed. These included (1) appreciable reduction of facial height, most marked in the maxilla and mandible, and strongly correlated with loss of teeth, (2) modest increase in facial width, (3) modest increase in facial depth, except in those regions associated with tooth loss, and (4) general coarsening of bony prominences. Histomorphic analysis demonstrated increasing porosity with age, more marked in the female population. Although these changes represent population trends, in any given patient, any or all of them may be present to varying degrees. Surgeons should be aware of these possibilities and consider selective alterations of the skeletal foundation, either separately or in concert with the overlying soft-tissue envelope, in order to optimize the results of surgery for the aging face.     

Variation in life-history characteristics among populations of North American wood turtles: a view from the north

Life-history traits such as age at maturity, body size and clutch size tend to vary across a species' distribution. The purpose of our study was to describe the demography of a newly discovered population of North American wood turtles Glyptemys insculpta at the species' northern range limit, and to compare our findings to those of other studies to test hypotheses about adaptive life-history variation. Turtles were hand-captured from May to October 2005 and 2006 along a 4.5 km stretch of river located in the Sudbury District, ON, Canada (46°N). Fifty-five captured individuals provided a population density estimate of 1.3 turtles/100 m of river. Juveniles comprised 35% of wood turtles captured, and growth ring counts (i.e. age estimates) indicated recruitment in each of the past 11 years. Among populations, we found a nonlinear pattern in body size variation with the largest turtles in the north, smallest turtles in the centre of the range, and intermediate-sized turtles in the south. This nonlinear pattern in body size was reflected in clutch size variation. Selective pressures to overcome years of low recruitment may have resulted in larger body sizes and hence large clutch sizes at northern latitudes while conspecifics at southern latitudes can achieve larger body sizes because they live in a more productive environment. Population density decreased with latitude, likely as a result of a gradient in habitat productivity.     

Association among obesity-related anthropometric phenotypes: analyzing genetic and environmental contribution

Obesity has become a public-health and policy problem in many parts of the world. Epidemiological and population studies in this field are usually based on different anthropometric measures; however, common genetic and environmental factors between these phenotypes have been scarcely studied. The objective of this article is to assess the strength of these factors on the covariation among a large set of obesity-related traits. The subject group consisted of 533 nuclear families living in the Greater Bilbao (Spain), and included 1,702 individuals aged 2-61 years. Detailed anthropometric measurements (stature, breadths, circumferences and skinfolds) were carried out in each subject. Bivariate quantitative genetic analyses were performed using a variance-components procedure implemented in the software SOLAR. The results revealed that the majority of these traits is affected by common genetic and environmental factors. All correlations were significantly different from 1 and varied from non-significant to very high (>0.90, P < 0.0001), with clearly lower pleiotropic effects among pairs including fat-distribution traits. Despite the strong common genetic effects detected among phenotypes determining the amount of body fat and mass, there is a residual genetic influence on the local fatness measures that cannot be explained exclusively by the genetic influence on overall fatness. Moreover, the observed relationships confirm a partially different genetic control of truncal and peripheral fat. In conclusion, our findings highlight the relevance of considering different types of traits in the prevention and treatment of obesity, as well as in the search for genes involved in its development.     

Spatial Variation in Soil Properties among North American Ecosystems and Guidelines for Sampling Designs

Soils are highly variable at many spatial scales, which makes designing studies to accurately estimate the mean value of soil properties across space challenging. The spatial correlation structure is critical to develop robust sampling strategies (e.g., sample size and sample spacing). Current guidelines for designing studies recommend conducting preliminary investigation(s) to characterize this structure, but are rarely followed and sampling designs are often defined by logistics rather than quantitative considerations. The spatial variability of soils was assessed across ∼1 ha at 60 sites. Sites were chosen to represent key US ecosystems as part of a scaling strategy deployed by the National Ecological Observatory Network. We measured soil temperature (T_s) and water content (SWC) because these properties mediate biological/biogeochemical processes below- and above-ground, and quantified spatial variability using semivariograms to estimate spatial correlation. We developed quantitative guidelines to inform sample size and sample spacing for future soil studies, e.g., 20 samples were sufficient to measure T_s to within 10% of the mean with 90% confidence at every temperate and sub-tropical site during the growing season, whereas an order of magnitude more samples were needed to meet this accuracy at some high-latitude sites. SWC was significantly more variable than T_s at most sites, resulting in at least 10× more SWC samples needed to meet the same accuracy requirement. Previous studies investigated the relationship between the mean and variability (i.e., sill) of SWC across space at individual sites across time and have often (but not always) observed the variance or standard deviation peaking at intermediate values of SWC and decreasing at low and high SWC. Finally, we quantified how far apart samples must be spaced to be statistically independent. Semivariance structures from 10 of the 12-dominant soil orders across the US were estimated, advancing our continental-scale understanding of soil behavior.     

HLA and mate selection: no evidence in South Amerindians.

There have been reports of nonrandom mating (negative-assortative mating) or preference for individuals of different major histocompatibility complex (MHC) genotypes in both mice and humans. We have examined the association of HLA-A and HLA-B genotypes, both for each locus by itself and for two-locus genotypes, in mates of 194 couples from 11 South Amerindian tribes. The proportion of couples sampled averaged >50% of the total matings with progeny for 10 of the tribes. In nearly all cases, HLA-sharing proportions were very close to those expected from random mating, suggesting strong negative-assortative mating for MHC is not present in these South Amerindians.     

Dental caries, enamel composition, and subsistence among prehistoric Amerindians of Ohio

Six populations of prehistoric Amerindians from Ohio are sampled to establish the relationship of enamel composition and dental caries experience. The populations used included groups practicing hunting-gathering-fishing and maize horticulture, and they represent at least two major cultural traditions, the Late Archaic/Glacial Kame (1000-500 BC) and the Fort Ancient and Sandusky Bay Traditions (AD) 1200-1600). Characterization of enamel composition is achieved using scanning electron microscopy energy-dispersive X-ray analysis. Thirteen elements present are quantified, and they are analyzed with respect to each population's subsistence base using correspondence analysis. Evaluations of cariogenic and cariostatic effects of elements are made on the basis of caries frequency comparisons among the populations. Results indicate that zinc, copper, iron, nickel, and calcium-phosphorus ratio distinguish populations exhibiting high, moderate, and low caries frequency as well as discriminate hunter-gathers from maize horticulturalists.