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1.
The incidence of 30 minor non-metrical cranial variants in Australian Aborigines discussed in a previous publication is compared with incidence in crania from Melanesia and Polynesia. With the qualification that the sample sizes from Melanesia and Polynesia are rather small, the data indicate that the differences between Australia and Melanesia and Polynesia exceed those between the three areas into which Australia was divided. The area of Australia made up of the Northern Territory and northern Western Australia has more association with Melanesia than Polynesia as expected, while the more southern regions of Australia have more association with Polynesia than Melanesia perhaps by migrations from Asia. Because the southern Australian Aborigines are now largely extinct, it seems difficult to prove this.  相似文献   

2.
A nearly complete human skeleton dating to the Early Holocene (epi-Paleolithic culture) excavated from Gua Gunung Runtuh, Malaysia, is described. Cranial, dental, and limb bone measurements are recorded on the skeleton, and compared with early and modern skeletal samples from Southeast Asia and Australia. The comparisons demonstrate that the Gua Gunung specimen is most similar to Australian Aborigines in dental and limb measurements, while the cranial measurements indicate a close affinity to Mesolithic samples from Malaysia and Flores. These findings further suggest that the Gua Gunung skeleton, as well as other fossils from Tabon and Niah, are representative of an early group of people who occupied Sundaland during the late Pleistocene, and may be the ancestors of Australian Aborigines. Some of the dental and limb bone measurements exhibited by the ancestors persist in Southeast Asian populations until the early Holocene. Differences in cranial traits have, however, accumulated since the late Pleistocene in Australian Aborigines and early Southeast Asian peoples. Am J Phys Anthropol 109:327–340, 1999. © 1999 Wiley-Liss, Inc.  相似文献   

3.
We examined the population structure and genetic variation of four genomic regions within and between 30 Citrus tristeza virus (CTV) isolates from Spain and California. Our analyses showed that most isolates contained a population of sequence variants, with one being predominant. Four isolates showed two major sequence variants in some genomic regions. The two major variants of three of these isolates showed very low nucleotide identity to each other but were very similar to those of other isolates, suggesting the possibility of mixed infections with two divergent isolates. Incongruencies of phylogenetic relationships in the different genomic regions and statistical analyses suggested that the genomes of some CTV sequence variants originated by recombination events between diverged sequence variants. No correlation was observed between geographic origin and nucleotide distance, and thus from a genetic view, the Spanish and Californian isolates analyzed here could be considered members of the same population.  相似文献   

4.
Heterochrony is widely regarded as an important evolutionary mechanism, one that may underlie most, if not all, morphological evolution, yet relatively few studies have examined variation in the sequence of development. Even fewer studies have been designed so that intraspecific variation in the relative sequence of developmental events can be assessed, although this variation must be the basis for evolutionary change. Intraspecific variation in developmental ossification sequences was documented from the zebrafish (Danio rerio) by Cubbage and Mabee (1996) and from the Siamese fighting fish (Betta splendens) by Mabee and Trendler (1996), but a quantitative analysis of the patterns within this variation was not made. Here, we quantify the effect of rearing temperature on the sequence of ossification and characterize the levels and patterns of intraspecific variation in these fishes. For Danio, there were no temperature effects on the sequence of bone development across the cranium, cranial region development, cartilage versus dermal bones, or lateral line bone versus nonassociated bones. Likewise the level of variation in relative sequence (position) of ossification was low, about two ranks, across temperatures. At higher temperatures, we found higher levels of variation in iterated cranial bones and less in bones forming early in the sequence. No temperature effects on variation were found among regions, between lateral line-associated bones and nonassociated bones, between median and paired bones, or across the entire sequence, indicating concordant variability among the three temperatures. Individual bones with the highest levels of variability were not consistent among temperatures. Baseline patterns of intraspecific variation in Danio were compared to those of Betta. For both species, the level of intraspecific variation in sequence position was low and the variability of cranial bones was concordant. Individual bones with the highest levels of variability were not consistent between species. In both species, variation was widespread (distributed evenly across the sequence). We used comparisons (among regions, between dermal and cartilage bones, between lateral line-associated and other bones, between median and paired bones, between iterated and noniterated bones, between feeding-associated bones and others) to see which subsets were most variable and thus potentially useful in predicting high levels of evolutionary change. The only subset of bones that was significantly more variable than others was cartilage bones. If interspecific patterns are parallel to these intraspecific differences, cartilage bones would be expected to show higher levels of heterochrony. Although concordance across the cranial ossification sequence and among regions in Danio, Betta, and two other teleosts, Oryzias and Barbus, suggests an evolutionarily conserved pattern of ossification, identity in sequence position across taxa was not observed for any bone. Thus, variation existed in sequence position across temperatures and species. Intraspecific variation of this sort may influence the morphological outcome and evolutionary trajectories of species.  相似文献   

5.
孙虎  韩良  佟连军  孔凡娥 《生态学报》2006,26(5):1597-1604
通过生态意义下区域竞争力的研究,提出了经济自由空间的概念.在进行模型静态和动态的分析后,得出科技的进步对区域潜在竞争力具有决定性作用的结论.在实证研究方面,运用因子分析的方法,根据生态水平、人均国内生产总值和生态科技进步等13个指标,对全国31个省(自治区、直辖市)的生态经济水平以及区域竞争力进行了排名.结果发现,由于经济发展水平和自然生态环境等原因,在生态意义下我国各个区域的区域竞争力也成空间上的东、中、西分布格局.在上述理论和实证探讨的基础上,还分别就生态条件下区域发展的公平和效率以及生态条件下有关不发达地区的区域政策进行了探讨.认为生态条件下,如果政策制定不得当,不发达地区会处于更加不平等的地位,所以政策制定者应该重新认识传统的区域理论和区域政策.  相似文献   

6.
A tribal aboriginal community, the Mowanjum, from the Kimberley region in Western Australia has been screened to determine the extent of genetic variation in the products of genes coding for apolipoproteins, which are intimately involved in lipid metabolism. Of the seven systems tested, APOE and APOH revealed common structural variations, but their distribution patterns are significantly different from those found in European populations. Australian Aborigines were found to be unique because they have no APOE*2 and APOH*3 alleles and have strikingly high frequencies of the APOE*4 (26%) and APOH*1 (13%) alleles. The contrast in variation observed at these apolipoprotein loci between Australian Aborigines and Europeans not only makes these loci useful genetic markers in biologic anthropology studies but also provides a unique opportunity to investigate the role of genetic-environment interaction in determining interpopulation differences in cardiovascular disease risk factors.  相似文献   

7.
The number of "private" electrophoretic variants of enzymes controlled by 25 loci has been used to obtain estimates of mutation rate in Australian Aborigines. Three different methods yield values of 6.11 X 10(-6), 2.78 X 10(-6), and 12.86 X 10(-6)/locus per generation for the total sample of Aborigines. One tribal population of Waljbiri in central Australia gives values of 2.99 X 10(-6) and 2.04 X 10(-6) for two of the methods, the third being unapplicable. The mean mutation rate for the total Aboriginal sample of 7.25 X 10(-6) is very similar to the value obtained by Neel and his colleagues for Amerindians in South America.  相似文献   

8.
The vertebral column of fishes has traditionally been divided into just two distinct regions, abdominal and caudal. Recently, however, developmental, morphological, and mechanical investigations have brought this traditional regionalization scheme into question. Alternative regionalization schema advocate the division of the abdominal vertebrae into cervical, abdominal, and in some cases, transitional regions. Here, we investigate regional variation at the level of the vertebrae and intervertebral joint (IVJ) tissues in the striped bass, Morone saxatilis. We use gross dissection, histology, and polarized light imaging to quantify vertebral height, width, length, IVJ length, IVJ tissue volume and cross‐sectional area, and vertical septum fiber populations, and angles of insertion. Our results reveal regional differences between the first four (most rostral) abdominal vertebrae and IVJs and the next six abdominal vertebrae and IVJs, supporting the recognition of a distinct cervical region. We found significant variation in vertebral length, width, and height from cranial to caudal. In addition, we see a significant decline in the volume of notochordal cells and the cross‐sectional area of the fibrous sheath from cranial to caudal. Further, polarized light imaging revealed four distinct fiber populations within the vertical septum in the cervical and abdominal regions in contrast with just one fiber population found in the caudal region. Measurement of the insertion angles of these fiber populations revealed significant differences between the cervical and abdominal regions. Differences in vertebral, IVJ, and vertical septum morphology all predict greater range of motion and decreased stiffness in the caudal region of the fish compared with the cervical and abdominal regions. J. Morphol., 2012. © 2011 Wiley Periodicals, Inc.  相似文献   

9.
Ian Abbott 《Oecologia》1979,44(3):347-354
Summary The occurrence of kangaroos, wallabies and related species (Family Macropodidae) on islands of area 90 ha or more round Australia is non-random. Few islands adjacent to the northwestern, northern and eastern coasts have macropods present in contrast to a large number of islands near the mid-and southwestern coasts and most of the southern coastline. The latter group of islands was not visited by aborigines because they lacked watercraft, and most of the islands were apparently too small to support human populations. It is argued that Aboriginal man, through direct predation, his introduction of the Dingo, and his frequent use of fire, was chiefly responsible for the difference in representation of macropods on the two groups of islands.The median area of islands with at least one macropod species present and which are used by Aborigines is about six times larger than that of islands with at least one macropod species present and not visited or occupied by Aborigines. Several possible alternative hypotheses to account for the distribution pattern described above are discussed. For two of these hypotheses inadequate data are at hand to assess their significance.It is suggested that the median area of islands visited or occupied by Aborigines provides a guide to reserve sizes necessary for the conservation of macropods on mainland Australia. Areas of at least 5,000 ha are probably needed for the local long-term persistence of at least one species of macropod, and areas of 9,000 ha for the long-term survival in reserves of at least two macropod species.  相似文献   

10.
To get a better understanding of the effect of interelement selection on the variation of long terminal repeat retrotransposon families, we have investigated the evolutionary history of blood in the Drosophila melanogaster species complex. We carried out a PCR approach to amplify the 5′ untranslated region from blood in the four species of the complex. This procedure revealed two main classes of size variants. Phylogenetic analyses of nucleotide sequences from these variants and blood elements from the Drosophila Genome Projects database show that elements are grouped according to their size, so that they probably correspond to two subfamilies. These two subfamilies arose prior to the split of the complex, and several facts indicate that the expansion of one of them is leading to the competitive exclusion of the other, at least from the euchromatic regions of the genome. Received: 17 August 2000 / Accepted: 20 November 2000  相似文献   

11.
The people associated with the Jomon culture, the Neolithic inhabitants of Japan, are one of the key groups in the population history of East Asia, because they retain many archaic characters that may be traced back to Eurasian Upper Palaeolithic hunter–gatherers. In this study, the regional diversity of the Jomon skeletal series was estimated by applying the R‐matrix method to 34 craniofacial measurements. The patterns of intraregional variation indicate little effect on the genetic structure of the Jomon from long‐term gene flow stemming from an outside source. The regional diversities were further estimated by pooling all individuals into regional aggregates, and by computing the mean variance within local groups in each region. Although the pattern of phenotypic variation differs depending on the unit of analysis, the gradient of the diversity retains its identity. The Hokkaido region, the northernmost part of the Japanese archipelago, has the highest variance, followed by the regions of eastern Japan, while the southwestern regions have the lowest variance. These findings suggest that the Jomon ancestors of the northern part of Japan might have expanded southward to Honshu Island. Global analyses including samples from Eurasia, Africa, and Australia dating roughly to the same chronological periods as those of the Jomon samples, indicate that the Jomon cranial series share part of their ancestral gene pool with early northeastern Asians. The present findings support the archeologically suggested population growth and expansion in the northern half of the Eurasian continent during the late Pleistocene and early Holocene periods. Am J Phys Anthropol, 2009. © 2008 Wiley‐Liss, Inc.  相似文献   

12.
The number of variants that have a non-zero effect on a trait (i.e. polygenicity) is a fundamental parameter in the study of the genetic architecture of a complex trait. Although many previous studies have investigated polygenicity at a genome-wide scale, a detailed understanding of how polygenicity varies across genomic regions is currently lacking. In this work, we propose an accurate and scalable statistical framework to estimate regional polygenicity for a complex trait. We show that our approach yields approximately unbiased estimates of regional polygenicity in simulations across a wide-range of various genetic architectures. We then partition the polygenicity of anthropometric and blood pressure traits across 6-Mb genomic regions (N = 290K, UK Biobank) and observe that all analyzed traits are highly polygenic: over one-third of regions harbor at least one causal variant for each of the traits analyzed. Additionally, we observe wide variation in regional polygenicity: on average across all traits, 48.9% of regions contain at least 5 causal SNPs, 5.44% of regions contain at least 50 causal SNPs. Finally, we find that heritability is proportional to polygenicity at the regional level, which is consistent with the hypothesis that heritability enrichments are largely driven by the variation in the number of causal SNPs.  相似文献   

13.
14.
Abstract

Blue penguins, Eudyptula minor, breeding on Penguin Island, Western Australia are considerably larger than other blue penguins in Australia. If genetic isolation is the cause, it may have implications for the conservation status of some blue penguin populations. We compared the sequences of two mitochondrial gene regions (cytochrome‐b and the control region) from Western Australian blue penguins with other populations of blue penguins from Australia and New Zealand. We found few differences between sequences from Western Australia, Phillip Island, Victoria and Otago, New Zealand, although all three differed considerably from other New Zealand blue penguins. Sequences for the control region from the Western Australian blue penguins and 30 more birds breeding at various Australasian sites provided further support for two major clades within Eudyptula; an Australian clade (including Otago) and a New Zealand clade.  相似文献   

15.
Summary Sodium dodecyl sulphate (SDS) gel electrophoresis shows distinct differences in the number and mobility of the major salivary proteins produced by various stocks of Drosophila melanogaster. Genetic analysis showed that the variation was due to the presence of allelic forms of these proteins and demonstrated the absence of certain types of modifying genes. The variation in the mobility of two non-allelic proteins is so large that it is not possible to group variants of these proteins into specific mobility classes. Some results from the genetic analysis of these variants are of relevance to similar analyses of groups of genes determining related proteins in Drosophila.  相似文献   

16.
Aboriginal fire management in south-eastern Australia: aims and frequency   总被引:2,自引:0,他引:2  
Aim To examine the purpose of burning by Aborigines of south‐eastern Australia. Location South‐eastern Australia. Methods A survey of the ethnography and ecology relating to Aboriginal fire. Results Ecologists have only recently acknowledged the past history of Aboriginal burning. Its purpose was to maximise plant and animal food resources. Main Conclusions The seasonal timing and frequency of Aboriginal burning is embedded in various ecosystems.  相似文献   

17.
Following the elucidation by geneticists of the nature of minor skeletal variants in the mouse, anthropologists have stressed the potential of these traits for tracing the affinities and movements of extinct human populations. Earlier Sullivan observed that discrete traits could be particularly valuable where artificial cranial deformation limits the use of craniometry. Twenty-eight minor variants were studied in bifronto-occipitally deformed and undeformed skulls of a sample of 78 from a single Hopewell mound. The pattern of frequency differences between deformed and undeformed with respect to traits at the back of the vault and in the frontal region, interpreted in developmental terms, reveals a hypostotic effect in these regions in the deformed skull; while, in contrast, traits of the lateral vault, facial skeleton and cranial base point to a general hyperostotic effect in these regions. Each of three emissaria tends to be more constant in the deformed. That minor cranial variants manifest a plastic response to this type of environmentally-imposed stress is consistent with the nature of such variants as elucidated by genetics research in mice. The findings suggest that deformed crania should be excluded from population studies in which genetic divergence between groups is estimated in terms of cranial trait frequencies.  相似文献   

18.
Introductory comments concern the duality of some Australian Aboriginal social organi-zations, particularly with respect to ritual action and the enunciation of rights to land. Ethnographic data are presented from the north of Western Australia. Aborigines in this region own land which they inherit and members of a patri-moiety realize their rights in land through subsequent ritual performances. However, members of their opposed patrimoiety who are also land owners play an indispensible role in any ritual action, so that members of both moieties are dependent upon one anothelr in the exercise of rights to land. Further data are provided which show the complex ritual and social relationship between four landowners in the region. It is concluded that the four men are mutually dependent in matters relating to their land. Consequently, Aborigines in the region stress the joint ownership and sharing of land, rather than their independence.  相似文献   

19.
Despite the fact that heterochronic processes seem to be an important process determining morphological evolution of the delphinid skull, previous workers have not found allometric scaling as relevant factor in the differentiation within the genus Sotalia. Here we analyzed the skull ontogeny of the estuarine dolphin S. guianensis and investigate differential growth and shape changes of two cranial regions – the neurocranium and the face – in order to evaluate the relevance of cranial compartmentalization on the ontogeny of this structure. Our results show that, even though both cranial regions stop growing at adulthood, the face has higher initial growth rates than the neurocranium. The rate of shape changes is also different for both regions, with the face showing a initially higher, but rapidly decreasing rate of change, while the neurocranium shows a slow decreasing rate, leading to persistent and localized shape changes throughout adult life, a pattern that could be related to epigenetic regional factors. The pattern of ontogenetic shape change described here is similar to those described for other groups of Delphinidae and also match intra and interspecific variation found within the family, suggesting that mosaic heterochrony could be an important factor in the morphological evolution of this group.  相似文献   

20.
W. Stephan  S. J. Mitchell 《Genetics》1992,132(4):1039-1045
We have estimated DNA sequence variation within and between two populations of Drosophila ananassae, using six-cutter restriction site variation at vermilion (v) and furrowed (fw). These two gene regions are located close to the centromere on the left and right X chromosome arms, respectively. In the fw region, no DNA polymorphism was detected within each population. In the v region, average heterozygosity per nucleotide was very low in both populations (pi = 0.0005 in the Burma population, and 0.0009 in the India population). These estimates are significantly lower than those from loci in more distal gene regions. The distribution of DNA polymorphisms between both populations was also striking. At fw, three fixed differences between the Burma and India populations were detected (two restriction site differences and one insertion/deletion of approximately 2 kb). At v, each DNA polymorphism in high frequency in the total sample was nearly fixed in one or the other population, although none of them reached complete fixation. The observed pattern of reduced variation within populations and fixed differences between populations appears to correlate with recombination rate. We conclude that recent hitchhiking associated with directional selection is the best explanation for this pattern. The data indicate that different selective sweeps have occurred in the two populations. The possible role of genetic hitchhiking in rapid population differentiation in gene regions of restricted recombination is discussed.  相似文献   

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