Affinities of the Swartkrans 847 hominid cranium

Further evidence of the presence of a second hominid species at the Swartkrans locality was obtained in 1969 when the SK.847 specimen was discovered by us to represent the same individual as the SK.80 maxilla. The SK.847 specimen had previously been regarded as robust australopithecine, whereas the latter was first attributed to Telanthropus capensis and subsequently to a species of the genus Homo. Recent criticism of our interpretation of these remains has not evaluated and analyzed critically the primary fossil evidence. Instead it relies on a strict adherence to an as yet unsubstantiated hypothesis that posits only a single hominid species at any point in space and time in the Cenozoic history of Hominidae.     

Geographical variations in the cranium ofSaguinus geoffroyi

In terms of craniometry, we examinedHershkovitz's hypotheses that, inSaguinus geoffroyi, populations on the western shore of the Rio Atrato were closely related toS. leucopus, and that a morphocline could be traced from the easternS. geoffroyi population to the western one. We detected a morphological sequence from east to west (or east to west) but did not find any evidence supporting the former hypothesis.     

The anthropological value of minor variants of the dental crown

The incidences of 31 minor variants of the dental crown were scored from dental casts of samples taken from six European populations. Although several variants showed significant sex bias in one or other sample, only one (pits instead of furrow on premolar₂) consistently favoured one sex. Associations between the variants were sought. Although few consistent associations were demonstrated, there was a possible tendency for extra cusps to occur together throughout the dentition. Distance statistics calculated between the samples were compatible with the expected genetical relationships of the samples, but only modern samples could be used since variants were destroyed by attrition in archeological samples. Before such distances can be considered reliable, it is necessary to know:

• i the extent to which environmental factors such as diet influence variant expression.
• ii whether or not variant bearing teeth are selectively destroyed by caries, which in civilised populations render a high proportion of most dentitions unscoreable.

     

Cryptic population structuring in Scandinavian lynx: reply to Pamilo

In a recent Commentary in this journal, Pamilo (2004) criticized our analysis of the spatial genetic structure of the Eurasian lynx in Scandinavia (Rueness et al. 2003). The analyses uncovered a marked geographical differentiation along the Scandinavian peninsula with an apparent linear gradient in the north-south direction. We used computer simulations to check on the proposition that the observed geographical structure could have arisen by genetic drift and isolation by distance in the approximate 25 generations that have passed since the last bottleneck. Pamilo disapproved of our choice of population model and also how we compared the outcome of the simulations with data. As these issues should be of interest to a wider audience we discuss them in some detail.     

Morphological variations of the cranium within the genusLeontopithecus

Multivariate analysis methods were applied to the cranial measurements ofLeontopithecus. InLeontopithecus chrysomelas, the face is generally narrow and the cranial shape is relatively unique. Especially, the male has extremely narrow face and quite unique cranial shape amongLeontopithecus. Leontopithecus rosalia has the broad face compared with the other species. The cranial size ofL. rosalia is as large as that ofL. chrysomelas. Male ofLeontopithecus chrysopygus is the largest in overall size of the cranium, and has the widest braincase.     

A geometric morphometric analysis of heterochrony in the cranium of chimpanzees and bonobos

Despite several decades of research, there remains a lack of consensus on the extent to which bonobos are paedomorphic (juvenilized) chimpanzees in terms of cranial morphology. This study reexamines the issue by comparing the ontogeny of cranial shape in cross-sectional samples of bonobos (Pan paniscus) and chimpanzees (Pan troglodytes) using both internal and external 3D landmarks digitized from CT scans. Geometric morphometric methods were used to quantify shape and size; dental-maturation criteria were used to estimate relative dental age. Heterochrony was evaluated using combined size-shape (allometry) and shape-age relationships for the entire cranium, the face, and the braincase. These analyses indicate that the bonobo skull is paedomorphic relative to the chimpanzee for the first principal component of size-related shape variation, most likely via a mechanism of postformation (paedomorphosis due to initial shape underdevelopment). However, the results also indicate that not all aspects of shape differences between the two species, particularly in the face, can be attributed to heterochronic transformation and that additional developmental differences must also have occurred during their evolution.     

A population study of the jugular foramen bridging of the human cranium

The author previously proposed a simple standard for diagnosing the jugular foramen bridging in man. The incidence of this bridging trait was investigated according to that standard in nine cranial series of East Indians, Micronesians, Japanese, Ainu, Mongols, Aleuts, Alaskan Eskimos, Canadian Eskimos, and Ontario Iroquois. No sex difference in incidence of the trait was recognized. Side difference in trait incidence was also slight but was statistically significant in the combined series of all the population samples examined. The bridging trait occurred more frequently on the right side than on the left side. Occurrences of the bridging trait were definitely associated between sides. Incidence of the trait was less in East Indians, Ontario Iroquois, and Micronesians, but greater in Alaskan Eskimos and Canadian Eskimos, the incidences in Japanese, Ainu, Aleuts, and Mongols being intermediate. The differences in trait incidence among the nine population samples were considered to reflect the differences in genetic compositions of these specific populations.     

Within and between race distances in population studies based on discrete traits of the human skull

A battery of 24 discrete cranial traits has been tested for its power to discriminate within- and between-race distances for the two principal North American indigenous populations: Indian (7 samples, N = 366) and Eskimo (7 samples, N = 451). One of the Indian samples, Dakota Sioux, has been split according to tribal subdivisions, the intra-tribal mean distance providing a parameter of very close relationship. In addition, two Negro samples provide a parameter of relationship phylogenetically remote from the Amerinds. Separate male-female analysis of the three largest samples indicates that distances for pooled samples are not seriously affected by the sex component. Within-race distances (C. A. B. Smith's Measure of Divergence, MD), are smaller than between-race at the .00001 level of significance (Mann-Whitney U test) for both Indian-Eskimo and Amerind-Negro comparisons. The features most powerful for Indian-Eskimo discrimination are revealed by their percent contribution to the mean of 49 MD's. The African heritage of American Blacks is reflected in a characteristic Negro pattern of trait frequencies different from the Amerind. This battery of features yields valid taxonomical information useful in conjunction with other physical data to reconstruct affinities of extinct populations.     

Frameworks of population obesity and the use of cultural consensus modeling in the study of environments contributing to obesity

Obesity in Eastern Europe has been linked to privilege and status prior to the collapse of communism, and to exposure to free-market economics after it. Neither formulation is a complete explanation, and it is useful to examine the potential value of other models of population obesity for the understanding of this phenomenon. These include those of: thrifty genotypes; obesogenic behaviour; obesogenic environments; nutrition transition; obesogenic culture; and biocultural interactions of genetics, environment, behaviour and culture. At the broadest level, obesity emerges from the interaction of thrifty genotype with obesogenic environment. However, defining obesogenic environments remains problematic, especially in relation to sociocultural factors. Furthermore, since different identity groups may share different values concerning the obesogenicity of the environment, a priori assumptions about group homogeneity may lead to flawed interpretations of the importance of sociocultural factors in obesogenic environments. A new way to identify cultural coherence of groups and populations in relation to environments contributing to obesity is put forward here, that of cultural consensus modeling.     

Mechanical surface analysis of bone: a case study of cut marks and enamel hypoplasia on a Neolithic cranium from Sweden

A method for measuring, recording, and studying fine surface irregularities in three dimensions is presented. The method, which involves recording the movements of a diamond-tipped stylus as it scans the surface being studied, is demonstrated on a Neolithic cranium from Sweden. The cranium emanates from a pile dwelling dated to about 3000 B.C. Its frontal bone exhibits distinct cut marks indicative of scalping, and the teeth show signs of enamel hypoplasia. The surface topography of the putative cut marks and hypoplastic enamel were investigated using the stylus method. Measurements of enamel hypoplasia were also carried out for comparison on a front tooth from the lower jaw, and the cut mark study was compared with scanning electron micrographs. The results of this case study demonstrate that the stylus method can obtain high-resolution measurements of fine surface details directly on the original bone without preparation of or damage to the specimen.     

The cranium of Proviverra typica (Mammalia,Hyaenodonta) and its impact on hyaenodont phylogeny and endocranial evolution

We describe the first endocast reconstruction of a hyaenodont mammal based on X‐ray microtomography. The endocast belongs to the type material of the European hyaenodont Proviverra typica. We performed phylogenetic analysis to contextualize the evolution of endocranial size and complexity in Hyaenodonta. We added several European hyaenodonts and modified several codings of the most recent character–taxon matrix established to question the relationships within Hyaenodonta. Including these new species in a phylogenetic analysis reveals a new clade: Hyaenodontoidea. Comparisons with several previously described endocasts show that there was an increase in complexity in the convolutions of the encephalon within Hyaenodontidae history. Moreover, the analysis of the encephalization quotient reveals that the endocranium of the Hyaenodonta is not smaller than those of fossil Carnivora or some extant Carnivora. Therefore, the extinction of Hyaenodonta may not be linked to the relative size of hyaenodont brains.     

The use of quantitative traits in the study of human population structure

Studies of human population structure and history have tended to use demographic and/or serological data for analysis. This paper reviews the methods and studies that incorporate quantitative traits (usually polygenic traits) in such analyses. Methods of assessing the degree and pattern of among-group variation are discussed, and are characterized as being model-free or model-bound. Model-free methods deal with the measure of overall populational differentiation and with comparative methods for describing the pattern of differentiation. Model-bound methods are used for direct incorporation into theoretical models of population structure in order to estimate genetic parameters, such as those in admixture and isolation by distance models. To date, studies have indicated that quantitative traits may often be used successfully in studies of human population structure, and show effects of microevolutionary forces on quantitative variation among populations.     

头骨三项非测量特征在中国古代人群中的分布差异

本文对11组中国古代人群头骨面部的犬齿窝、颧骨缘突和梨状孔上外侧部膨隆三项非测量特征进行了群体间出现率的差异性检验, 以探讨其在区分群体变异时是否有意义。应用两样本率差异的χ2检验,比较了这三项非测量特征在性别、人群和种族方面的差异。研究结果表明,男性犬齿窝的出现率所反映的种族差异比较明显。颧骨缘突的出现率在进行人群间比较时更具有意义。汉代以来, 梨状孔上外侧部膨隆在中国北方新疆地区的欧罗巴人种男性与华北北部地区及东北地区的蒙古人种男性间存在着显著性差异。笔者发现, 犬齿窝和梨状孔上外侧部膨隆这两项特征可能存在着比较紧密的相关性,即犬齿窝越发育, 梨状孔上外侧部也会较为膨隆。对于犬齿窝和梨状孔上外侧部膨隆的相关性及其产生机制, 笔者提出了两种假说: 其一是鼻部形态的改变引起了梨状孔上外侧部膨隆, 并进而导致了犬齿窝的发育; 其二是因为颌部特别是犬齿的功能减退,造成犬齿后上方的区域凹陷, 进而引起了梨状孔上外侧部膨隆状态。     

Genetic identification of immigrants to the Scandinavian wolf population

Continued gene flow is fundamental to the survival of small, isolated populations. However, geography and human intervention can often act contrary to this requirement. The Scandinavian wolf population is threatened with a loss of genetic variation yet limited in the accessibility to new immigrants by the geographical distance of this peninsular population from its nearest neighbouring population and by human reluctance to allow wolves in the northern reindeer-breeding areas. In this study, we describe the identification of immigrants into this population using autosomal microsatellites, and maternally inherited mtDNA. Samples of 14 wolves collected in the “dispersal corridor” in northern Sweden in 2002–2005 were compared with 185 resident Scandinavian wolves and 79 wolves from the neighbouring Finnish population. We identified four immigrant wolves, suggesting some westward migration, although only one of these is likely to still survive. The integration of such immigrants into the breeding population is necessary to assure the long-term survival of this isolated and inbred population and highlights the importance of genetics techniques to the management of threatened populations.     

The influence of geographic variations on the muscular activity in selected sports movements

Surface EMG (SEMG) has been used frequently to study motion techniques or skills, body positions, material or equipment used, training-methodology and learning processes in sports and ergonomics. Little if any information is available on the effect of the geographical environment on the neuromuscular control of an athlete or workman during his/her performance or effort.

Motions were chosen in Alpine skiing and cycling.

Thirty-one certified ski instructors and twelve professional road cyclists participated in the study of geographical variance and its impact on muscle activity.

SEMG was measured from the agonists and antagonists of the upper- and lower limb. Skiers were measured on downhill slopes ranging from 19 to 51% while the cyclists performed with different saddle positions on 2, 7 and 12% slope inclinations, respectively.

Verification of the variation of muscular intensity (IEMG) over the slope inclination during a simulated giant slalom indicated that the muscular activity increased with increasing slope angle and decreased with decreasing slope angle, while heart rate measured with short-range radio telemetry increased at a constant rate between start and finish independent of the geographical variations.

In a direct descent on different slopes % levels the integrated EMG is well related to the inclination (r=0.82) confirming the findings of the giant slalom.

In cycling we found that, regardless of the pelvis position, the muscular intensity of lower limb muscles increased with increasing slope inclination, while the muscular intensity of the arms decreased with the same increasing slope inclination. In addition the decreased intensity of the arm muscles remained significantly higher with the pelvis (saddle) fully forward.

The geography of the terrain did influence the neuromuscular work and therewith probably the performance also. The influence however, varies with specific circumstances and is coupled with items of variability of the equipment used and the body regions involved.     

Experimental study of the stability of expression of non-metrical threshold skeletal traits in inbred mice

The influence of some environmental factors during prenatal development on manifestation of non-metrical threshold skeletal traits in BALB/c inbred mice was studied. The factors under study were: introduction of metilthiouracil into the diet of pregnant females; injections of pregnant females with adrenocorticotropic or parathyreoid hormones; keeping the females at low temperatures (two regimens). Offsprings of the females treated were examined for twenty five skeletal characters using Berry-Sj?vold's method. Despite the fact that their body weights decreased in all experimental groups, phenetical distances between the treated and control groups were much smaller than those between different inbred strains. Reliability of genetical interpretation of interpopulational differences in non-metrical skeletal traits is higher for the characters which are not correlated with total body sizes.     

中国西北潜在蒸散时空演变特征及其定量化成因

潜在蒸散是区域干湿状况评价、作物需水量估算和水资源合理规划的关键因子。基于FAO推荐的Penman-Monteith公式和126个台站1961—2009年逐日气象观测资料估算西北干旱半干旱区的潜在蒸散量ET0,并对其空间分布特征进行了讨论。通过非参数化Sen趋势分析法和M-K统计检验法方法分析潜在蒸散的时间演变规律,并定量探讨了西北地区影响ET0变化的主导因素。结果表明:49 a来,西北地区ET0的年平均值约为980.63 mm,其中夏季的值最大,冬季的值最小。年平均ET0的大值区位于西北日照时数的高值中心,低值区主要位于海拔高,气温低的山区。西北地形和气候的多样性导致多年平均潜在蒸散的变化及其原因具有明显的时空差异。ET0的变化主要归因于风速和气温,而相对湿度和日照时数的作用较小。由于风速的负贡献超过气温的正贡献,导致年平均ET0整体上呈下降趋势。四季中,春冬两季的ET0缓慢上升,冬季的变化率是春季的两倍;夏秋两季的ET0有所下降,但只有夏季的变化趋势显著。春、夏、秋三季ET0变化的首要主导因子是风速,而冬季的首要主导因子是气温。空间上,西风带气候区ET0降低主要归因于风速的减小,陕南地区ET0下降主要归因于日照时数的减少,其它地区ET0上升的主要原因是气温的增加。     

A population genetic study in the Ochamchir region, Abkhazia, SSR

The reported longevity of residents of the Soviet Socialist Republic of the Caucasus has focused considerable attention on this population. However, little is known of the genetic composition of this population. With this in mind, several village populations of the Ochamchir Region, Abkhazia, SSR, were typed for 37 discrete genetic blood groups, erythrocyte and plasma protein loci. Gene and haplotype frequencies calculated for the polymorphic markers were determined and the results used in an analysis of intervillage heterogeneity and genetic distance analysis comparing the Abkhazians to European and Asian reference populations. The Abkhazians are approximately equal distance from European and West Asian populations in a genetic sense, and this is consistent with their geographical location. In addition to the usual genetic polymorphisms, rare electrophoretic variants were encountered at the lactate dehydrogenase A and phosphohexose isomerase loci. These results suggest that the population of the Ochamchir Region is relatively homogeneous and not distinctly different from its geographical neighbors.     

Surnames in Chile: a study of the population of Chile through isonymy

In Chile, the Hispanic dual surname system is used. To describe the isonymic structure of this country, the distribution of 16,277,255 surnames of 8,178,209 persons was studied in the 15 regions, the 54 provinces, and the 346 communes of the nation. The number of different surnames found was 72,667. Effective surname number (Fisher's α) for the entire country was 309.0, the average for regions was 240.8 ± 17.6, for provinces 209.2 ± 8.9, and for communes 178.7 ± 4.7. These values display a variation of inbreeding between administrative levels in the Chilean population, which can be attributed to the 'Prefecture effect' of Nei and Imaizumi. Matrices of isonymic distances between units within administrative levels were tested for correlation with geographic distance. The correlations were highest for provinces (r = 0.630 ± 0.019 for Euclidean distance) and lowest for communes (r = 0.366 ± 0.009 for Lasker's). The geographical distribution of the first three-dimensions of the Euclidean distance matrix suggests that population diffusion may have taken place from the north of the country toward the center and south. The prevalence of European plus European-Amerindian (95.4%) over Amerindian ethnicity (4.6%, CIA World Factbook) is compatible with diffusion of Caucasian groups over a low-density area populated by indigenous groups. The significant excess of maternal over paternal indigenous surnames indicates some asymmetric mating between nonAmerindian and Amerindian Chileans. The available studies of Y-markers and mt-markers are in agreement with this asymmetry. In the present work, we investigate the Chilean population with the aim of detecting its structure through the study of isonymy (Crow and Mange,1965) in the three administrative levels of the nation, namely 15 regions, 54 provinces, and 346 communes.