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1.
Two tribal groups from southern India--the Chenchus and Koyas--were analyzed for variation in mitochondrial DNA (mtDNA), the Y chromosome, and one autosomal locus and were compared with six caste groups from different parts of India, as well as with western and central Asians. In mtDNA phylogenetic analyses, the Chenchus and Koyas coalesce at Indian-specific branches of haplogroups M and N that cover populations of different social rank from all over the subcontinent. Coalescence times suggest early late Pleistocene settlement of southern Asia and suggest that there has not been total replacement of these settlers by later migrations. H, L, and R2 are the major Indian Y-chromosomal haplogroups that occur both in castes and in tribal populations and are rarely found outside the subcontinent. Haplogroup R1a, previously associated with the putative Indo-Aryan invasion, was found at its highest frequency in Punjab but also at a relatively high frequency (26%) in the Chenchu tribe. This finding, together with the higher R1a-associated short tandem repeat diversity in India and Iran compared with Europe and central Asia, suggests that southern and western Asia might be the source of this haplogroup. Haplotype frequencies of the MX1 locus of chromosome 21 distinguish Koyas and Chenchus, along with Indian caste groups, from European and eastern Asian populations. Taken together, these results show that Indian tribal and caste populations derive largely from the same genetic heritage of Pleistocene southern and western Asians and have received limited gene flow from external regions since the Holocene. The phylogeography of the primal mtDNA and Y-chromosome founders suggests that these southern Asian Pleistocene coastal settlers from Africa would have provided the inocula for the subsequent differentiation of the distinctive eastern and western Eurasian gene pools.  相似文献   

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Key message

Grain amaranth is an underutilized crop with high nutritional quality from the Americas. Emerging genomic and biotechnological tools are becoming available that allow the integration of novel breeding techniques for rapid improvement of amaranth and other underutilized crops.

Abstract

Out of thousands of edible plants, only three cereals—maize, wheat and rice—are the major food sources for a majority of people worldwide. While these crops provide high amounts of calories, they are low in protein and other essential nutrients. The dependence on only few crops, with often narrow genetic basis, leads to a high vulnerability of modern cropping systems to the predicted climate change and accompanying weather extremes. Broadening our food sources through the integration of so-called orphan crops can help to mitigate the effects of environmental change and improve qualitative food security. Thousands of traditional crops are known, but have received little attention in the last century and breeding efforts were limited. Amaranth is such an underutilized pseudocereal that is of particular interest because of its balanced amino acid and micronutrient profiles. Additionally, the C4 photosynthetic pathway and ability to withstand environmental stress make the crop a suitable choice for future agricultural systems. Despite the potential of amaranth, efforts of genetic improvement lag considerably behind those of major crops. The progress in novel breeding methods and molecular techniques developed in model plants and major crops allow a rapid improvement of underutilized crops. Here, we review the history of amaranth and recent advances in genomic tools and give a concrete perspective how novel breeding techniques can be implemented into breeding programs. Our perspectives are transferable to many underutilized crops. The implementation of these could improve the nutritional quality and climate resilience of future cropping systems.
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North American Indian Jewelry and Adornment: From Prehistory to the Present. Lois Sherr Dubin. New York: Harry N. Abrams. 1999 608 pp.  相似文献   

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India currently has the world's second-largest population along with a fast-growing economy and significant economic disparity. It also continues to experience a high rate of infectious disease and increasingly higher rates of chronic diseases. However, India cannot afford to import expensive technologies and therapeutics nor can it, as an emerging economy, emulate the health-delivery systems of the developed world. Instead, to address these challenges it is looking to biotechnology-based innovation in the field of genomics. The Indian Genome Variation (IGV) consortium, a government-funded collaborative network among seven local institutions, is a reflection of these efforts. The IGV has recently developed the first large-scale database of genomic diversity in the Indian population that will facilitate research on disease predisposition, adverse drug reactions and population migration.  相似文献   

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《Marine Micropaleontology》2006,60(2):157-166
Deep-sea benthic foraminifera have been quantitatively analyzed in samples (> 125 μm size fraction) from Ocean Drilling Program (ODP) Site 238, to understand paleoceanographic changes in the Central Indian Basin over the past 1.9 Myr. Factor and cluster analyses of the 25 highest-ranked species made it possible to identify five biofacies, characterizing distinct deep-sea environmental settings. The environmental interpretation of each biofacies is based on the ecology of recent deep-sea benthic foraminifera. The benthic faunal record indicates fluctuating deep-sea conditions in environmental parameters including oxygenation, surface productivity and organic food supply. These changes appear to be linked to Indian summer monsoon variability, the main climatic feature of the Indian Ocean region. The benthic assemblages show a major shift at ∼ 0.7 to 0.6 Ma, marked by major turnovers in the relative abundances of species, coinciding with an increased amplitude of glacial cycles. These cycles appear to have influenced low latitude monsoonal climate as well as deep-sea conditions in the Central Indian Ocean Basin.  相似文献   

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洋县范坝旧石器地点位于秦岭南麓汉江上游的汉中盆地汉江左岸支流溢水河右岸第二级阶地上。为配合西安-成都高铁项目建设,2016年对该地点进行发掘,揭露面积171 m2,出土不同类型的石制品784件。范坝地点加工石制品的原料为遗址附近河流及河漫滩中的石英、石英岩、细砂岩、火成岩和燧石等砾石材料。硬锤打击法是主要的剥片方法,另外还有部分砸击法标本。石制品类型包括石锤、石核、石片、经过二次加工修理的石器、断块、碎屑及备料,石器组合中既存在尺寸较小的轻型刮削器,也有砍砸器、石球和重型刮削器等大型器物。遗址地层初步的光释光测年结果表明,汉江及其北部支流——溢水河第二级阶地上覆的堆积物形成时间为距今22~2.5万年之间,旧石器遗存的埋藏年代约为距今18~2.5万年的中更新世晚期至晚更新世阶段。  相似文献   

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Bailer AJ  Piegorsch WW 《Biometrics》2000,56(2):327-336
As appreciation for human impact on the environment has developed, so have the experimental systems and associated statistical tools that quantify this impact. Toxicological study in particular has grown in its complexity and its need for advanced statistical support. Within this perspective, we describe statistical practice in environmental toxicology and risk assessment. We present two case studies, one from mammalian toxicology and one from aquatic toxicology, that highlight the evolution of statistical practice in environmental toxicology.  相似文献   

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Published evidence of Oldowan stone exploitation generally supports the conclusion that patterns of raw material use were determined by local availability. This is contradicted by the results of systematic studies of raw material availability and use among the earliest known archaeological sites from Gona, Afar, Ethiopia. Artifact assemblages from six Pliocene archaeological sites were compared with six random cobble samples taken from associated conglomerates that record pene-contemporaneous raw material availability. Artifacts and cobbles were evaluated according to four variables intended to capture major elements of material quality: rock type, phenocryst percentage, average phenocryst size, and groundmass texture. Analyses of these variables provide evidence of hominid selectivity for raw material quality. These results demonstrate that raw material selectivity was a potential component of Oldowan technological organization from its earliest appearance and document a level of technological sophistication that is not always attributed to Pliocene hominids.  相似文献   

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The serine/threonine phosphatase calcineurin complex has been considered a prospective target for developing novel drugs due to its importance in fungal growth, virulence, and stress responses in pathogenic fungi. Therefore, two well-known immunosuppressants, FK506 and cyclosporine A were successfully identified to inhibit calcineurin by combining with FK506-binding protein 12 and cyclophilin A, respectively. However, these drugs are immunosuppressive and may exhibit serious side effects. There is a growing number of literatures reported on further exploring functions of the calcineurin complex as promising antifungal targets. In general, the majority of the calcineurin complex structures are conserved but some functions are species-specific. Nevertheless, there still have a lot of functional motifs in the calcineurin complex that are unexplored. Therefore, further investigation and experimentation into the calcineurin complex are strongly required. This review not only has summarized previous findings but also explored bioinformatics analysis along with structural models of the calcineurin complex for finding fungal-specific regions as potential targets, laying the groundwork for future research into new therapeutics.  相似文献   

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How axons in the developing nervous system successfully navigate to their correct targets is a fundamental problem in neurobiology. Understanding the mechanisms that mediate axon guidance will give important insight into how the nervous system is correctly wired during development and may have implications for therapeutic approaches to developmental brain disorders and nerve regeneration. Achieving this understanding will require unraveling the molecular logic that ensures the proper expression and localization of axon guidance cues and receptors, and elucidating the signaling events that regulate the growth cone cytoskeleton in response to guidance receptor activation. Studies of axon guidance at the midline of many experimental systems, from the ventral midline of Drosophila to the vertebrate spinal cord, have led to important mechanistic insights into the complex problem of wiring the nervous system. Here we review recent advances in understanding the regulation of midline axon guidance, with a particular emphasis on the contributions made from molecular genetic studies of invertebrate model systems.  相似文献   

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Genetic studies of 540 Paraguayan Indians from nine tribal groups and 51 Mennonites are presented for ABO, MNSs, P1, Rh, Kell, Lewis, Duffy, Diego; for serum immunoglobulins and haptoglobins, G6PD-deficiency, and thalassemia trait. Group O gene frequencies for all Indian groups were 1.00; for r (cde), 0.00. Tapiete, Lengua, Toba, and Sanapana Rz (CDE) frequencies were among the highest ever reported. N frequencies were high for Ache Kwera (Guayaki), Lengua, Cheroti, Guarayu, Tapiete; N and s low for Ayore. MS frequencies were high for Sanapana, Lengua, Ayore; Ns for Tapiete. Diego was notably absent for Toba, Lengua, Guarayu, Tapiete, Ayore. Homogeneous frequencies for Fya (1.000) occurred among Guarayu and Tapiete, and for P1 among Guayaki. Inv(a) frequencies were low for Cheroti, Chulupi, Guayaki. Hp 1 among Guayaki (Ache Kwera 0.15) is lowest ever reported. G6PD deficiency and abnormal hemoglobins were uniformly absent from all groups. Mennonite results were homogeneous and point toward Dutch origins. Differences among groups studied, and between Paraguayan and other Amerinds emphasize importance of genetic drift and founder principle. Abandonment of their tribes by mixed-blood offspring is partly responsible for apparent genetic purity and homogeneity of groups.  相似文献   

17.
The Indian Purple frog, Nasikabatrachus sahyadrensis, occupies a basal phylogenetic position among neobatrachian anurans and has a very unusual life history. Tadpoles have a large ventral oral sucker, which they use to cling to rocks in torrents, whereas metamorphs possess adaptations for life underground. The developmental changes that underlie these shifts in habits and habitats, and especially the internal remodeling of the cranial and postcranial skeleton, are unknown. Using a nearly complete metamorphic series from free-living larva to metamorph, we describe the postembryonic skeletal ontogeny of this ancient and unique monotypic lineage. The torrent-dwelling larva possesses a dorsoventrally flattened body and a head with tiny dorsal eyes, robust lower and upper jaw cartilages, well-developed trabecular horns, and a definable gap between the trabecular horns and the tip of the snout. Unlike tadpoles of many other frogs, those of Nasikabatrachus retain larval mouthparts into late metamorphic stages. This unusual feature enables the larvae to maintain their clinging habit until near the end of metamorphosis. The subsequent ontogenetic shift from clinging to digging is correlated with rapid morphological changes and behavioral modifications. Metamorphs are equipped with a shortened tibiafibula and ossified prehallical elements, which likely facilitate initial digging using the hind limbs. Subsequently, the frogs may shift to headfirst burrowing by using the wedge-shaped skull, anteriorly positioned pectoral girdle, well-developed humeral crests and spatula-shaped forelimbs. The transition from an aquatic life in torrents to a terrestrial life underground entails dramatic changes in skeletal morphology and function that represent an extreme in metamorphic remodeling. Our analysis enhances the scope for detailed comparative studies across anurans, a group renowned for the diversity of its life history strategies.  相似文献   

18.
Recent results from the zooarchaeological analysis of faunal remains from Vogelherd Cave, southwestern Germany, provide new insight into the subsistence behavior of early modern human groups during the Aurignacian. The results presented here represent the first comprehensive study of the archaeofauna from this site. Several episodes of occupation are inferred at this site, taking place primarily between 31 and 32 ka. Although a wide spectrum of Pleistocene mammals is represented in the Aurignacian at Vogelherd, reindeer (Rangifer tarandus) and horse (Equus ferus) were the primary prey taxa, and they are the most appropriate data sets with which to understand human subsistence on an intrasite level. Hunting of both taxa took place during the late summer and fall, coinciding with reindeer migrations and local abundance of horses. Complete or nearly complete prey carcasses were then transported from the kill locations to the cave for processing. This study shows that Vogelherd was a preferred locale of Aurignacian groups for a broad range of activities, including the time- and labor-intensive exploitation of ungulate prey for meat, marrow, and fat resources, as well as the production and maintenance of artifacts such as figurative artwork, personal ornaments, bone and ivory armatures, and lithic tools. With its rich faunal and artifact assemblages, the Aurignacian deposit at Vogelherd provides a wealth of information on this critical period of the early Upper Paleolithic, when cultural innovations were flourishing.  相似文献   

19.
C I Doris 《CMAJ》1995,153(9):1297-1300
Since the discovery of x-rays by Wilhelm Conrad Röntgen 100 years ago, diagnostic imaging has profoundly influenced the practice of medicine. As a result of discoveries during this period, ultrasonography, nuclear imaging, computed tomography and magnetic resonance imaging, as well as conventional radiography, have assumed a major role in diagnostic medicine. In addition to their traditional role in diagnosis, imaging techniques are becoming an increasingly important factor in innovative treatment methods, and this role is likely to expand. In the current climate of rising health care costs, radiologists and other health care providers who use imaging must increasingly account to health care funders for the cost-effectiveness of imaging in relation to other diagnostic and interventional techniques. They must also assure minimum standards of quality and training, and determine the appropriate role for diagnostic imaging in health care systems of the future.  相似文献   

20.
Organ, tissue and cell banking is currently an important method used to prevent death of cells in replacement transplantation therapy. From 1975 to 1985 the author performed experimental transplantations of islets isolated by collagenase digestion through injection into the liver through the portal vein, or by transplantation of minced neonatal pancreases under the renal capsule of alloxan or spreptozotocin into severely chronic diabetic rats and mice. Seventy of the 256 transplanted rats and mice were cured for 1 year, i.e. one-third of their life span, at the 3rd to 15th inbreeding and only 2 weeks of immunosuppression by azathioprine or cyclosporin A. The author compares his results with those achieved later with diabetic patients by whole pancreas transplantation, including prevention of diabetic renal and ocular complications, infertility, health of progeny of cured rats, and slow rejection and possibility of cure by repeated transplantation. He welcomes the return to islet transplantation, and possibly also of immunologically tolerant pancreatic stem cell transplantation, or transplantation of subcutaneous fibroblasts, transfected with a complex insulin gene, which will produce adequate insulin to prevent hyperglycemia, as does hepatic pyruvate kinase from an insulin analog, a therapy that will not need permanent immunosuppression.  相似文献   

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