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1.
Here we present evidence of phytoliths preserved in carbonised food deposits on prehistoric pottery from the western Baltic dating from 6,100 cal BP to 5750 cal BP. Based on comparisons to over 120 European and Asian species, our observations are consistent with phytolith morphologies observed in modern garlic mustard seed (Alliaria petiolata (M. Bieb) Cavara & Grande). As this seed has a strong flavour, little nutritional value, and the phytoliths are found in pots along with terrestrial and marine animal residues, these findings are the first direct evidence for the spicing of food in European prehistoric cuisine. Our evidence suggests a much greater antiquity to the spicing of foods than is evident from the macrofossil record, and challenges the view that plants were exploited by hunter-gatherers and early agriculturalists solely for energy requirements, rather than taste.  相似文献   

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Abstract The presence of distinctive types of JC virus (JCV) in the main ethnic groups suggests a close coevolution with the human host. However, phylogenetic trees of JCV show a basal clade of European lineages (Types 1/4), whereas trees of human genes are coherent in placing the first split between African and non-African populations. This discrepancy places into question the effectiveness of JCV as a marker of human population history. The present study investigates the evolution of JCV using a large set of fully sequenced strains. Their relationships are first elucidated by principal coordinates analysis. It is suggested that Type 6 from West Africa could represent the ancestral type, while the peculiar phylogeny of Types 1/4 could reflect their direct origin from the ancestral lineage. Further credit to the African origin of JCV is provided by a neighbor-joining analysis based on slow-evolving sites. Sequence analysis of fast-evolving sites reveals that the deep emergence of Types 1/4 in the tree does not reflect a real evolutionary divergence; rather it is the implicit result of a remarkably different G + C content. The hypothesis that Types 1/4 originated directly from Type 6 is confirmed by examining the pattern of variation at a few specific fast-evolving sites. On the basis of this approach, a twofold exit of JCV from Africa is hypothesized: one in the direction of the Eurasian continent and another limited to Europe. These findings suggest that two distinct migrations of individuals played a key role in the peopling of Europe during prehistoric times.  相似文献   

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Iceman: Uncovering the Life and Times of. Prehistoric Man Found in an Alpine Glacier. Brenda Fowler. New York: Random House, 2000.296 pp.  相似文献   

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Deedu (DU) Mongolians, who migrated from the Mongolian steppes to the Qinghai-Tibetan Plateau approximately 500 years ago, are challenged by environmental conditions similar to native Tibetan highlanders. Identification of adaptive genetic factors in this population could provide insight into coordinated physiological responses to this environment. Here we examine genomic and phenotypic variation in this unique population and present the first complete analysis of a Mongolian whole-genome sequence. High-density SNP array data demonstrate that DU Mongolians share genetic ancestry with other Mongolian as well as Tibetan populations, specifically in genomic regions related with adaptation to high altitude. Several selection candidate genes identified in DU Mongolians are shared with other Asian groups (e.g., EDAR), neighboring Tibetan populations (including high-altitude candidates EPAS1, PKLR, and CYP2E1), as well as genes previously hypothesized to be associated with metabolic adaptation (e.g., PPARG). Hemoglobin concentration, a trait associated with high-altitude adaptation in Tibetans, is at an intermediate level in DU Mongolians compared to Tibetans and Han Chinese at comparable altitude. Whole-genome sequence from a DU Mongolian (Tianjiao1) shows that about 2% of the genomic variants, including more than 300 protein-coding changes, are specific to this individual. Our analyses of DU Mongolians and the first Mongolian genome provide valuable insight into genetic adaptation to extreme environments.  相似文献   

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The physico-chemical characterization of a teleonomic event and the nature of the physico-chemical process by which teleonomic systems could emerge from non-teleonomic systems are addressed in this paper. It is proposed that teleonomic events are those whose primary directive is discerned to be non-thermodynamic, while regular (non-teleonomic) events are those whose primary directive is the traditional thermodynamic one. For the archetypal teleonomic event, cell multiplication, the non-thermodynamic directive can be identified as being a kinetic directive. It is concluded, therefore, that the process of emergence, whereby non-teleonomic replicating chemical systems were transformed into teleonomic ones, involved a switch in the primacy of thermodynamic and kinetic directives. It is proposed that the step where that transformation took place was the one in which some pre-metabolic replicating system acquired an energy-gathering capability, thereby becoming metabolic. Such a transformation was itself kinetically directed given that metabolic replicators tend to be kinetically more stable than non-metabolic ones. The analysis builds on our previous work that considers living systems to be a kinetic state of matteras opposed to the traditional thermodynamic states that dominate the inanimate world  相似文献   

8.
白莺山古茶的化学成分分析与栽培茶树的起源   总被引:3,自引:0,他引:3  
应用高压液相色谱(HPLC)技术,对白莺山古茶的大理茶素、儿茶素类、茶掊素、没食子酸、咖啡因和茶氨酸的含量进行分析.同时,应用分光光度法测定茶多糖和茶多酚含量.在与野生大理茶及栽培大叶茶(普洱生茶)进行多成分比较的基础上,结合形态性状的变异与进化,讨论白莺山古茶种质资源的多样性与野生大理茶和栽培大叶茶的相互关系.分析研究结果不仅为白莺山古茶的品质评价提供可靠的科学数据,为白莺山丰富的古茶种质资源的深人系统研究和合理开发利用提供基础,同时,通过多种过渡类型的化学成分分析与比较,为栽培大叶茶的起源和大理茶作为大叶茶的野生基源之一的假说提供了植物化学方面的证据.  相似文献   

9.
Based on mitochondrial DNA (mtDNA), it has been estimated that at least 15 founder haplogroups peopled the Americas. Subhaplogroup C1d3 was defined based on the mitogenome of a living individual from Uruguay that carried a lineage previously identified in hypervariable region I sequences from ancient and modern Uruguayan individuals. When complete mitogenomes were studied, additional substitutions were found in the coding region of the mitochondrial genome. Using a complete ancient mitogenome and three modern mitogenomes, we aim to clarify the ancestral state of subhaplogroup C1d3 and to better understand the peopling of the region of the Río de la Plata basin, as well as of the builders of the mounds from which the ancient individuals were recovered. The ancient mitogenome, belonging to a female dated to 1,610±46 years before present, was identical to the mitogenome of one of the modern individuals. All individuals share the mutations defining subhaplogroup C1d3. We estimated an age of 8,974 (5,748–12,261) years for the most recent common ancestor of C1d3, in agreement with the initial peopling of the geographic region. No individuals belonging to the defined lineage were found outside of Uruguay, which raises questions regarding the mobility of the prehistoric inhabitants of the country. Moreover, the present study shows the continuity of Native lineages over at least 6,000 years.  相似文献   

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The contents of dalichasu (1,2-di-O-galloyl-4,6-O-(S) hexahydroxydiphenoyl-β-D-glucopyranose), catechins, theogallin, gallic acid, caffeine and theanine in old tea trees from Bai Ying Shan mountain were quantitatively analyzed by HPLC method, while their total polysaccharides and polyphenols were measured by an UV Vis spectrophotometer. Based on the chemical composition and morphological variation, the germplasm resource diversity of tea trees in Bai Ying Shan Mountain and their relationship with wild Camellia taliensis and cultivated tea (Csinensis var assamica) were discussed. The results provided not only the scientific data of quality evaluation of the old tea trees in Bai Ying Shan Mountain, but also the chemical evidence for the origin of cultivated tea and the hypothesis that Ctaliensis might be one of the origins of cultivated tea during the long natural variation and artificial breeding.  相似文献   

13.
We investigated the possible existence of chemical shift of water nuclei in Artemia cysts using high resolution nuclear magnetic resonance (NMR) methods. The results conducted at 60, 200, and 500 MHz revealed an unusually large chemical shift for intracellular water protons. After correcting for bulk susceptibility effects, a residual downfield chemical shift of 0.11 ppm was observed in fully hydrated cysts. Similar results have been observed for the deuterium and 17O nuclei.

We have ruled out unusual intracellular pH, diamagnetic susceptibility of intracellular water, or interaction of water molecules with lipids, glycerol, and/or trehalose as possible origins of the residual chemical shift. We conclude that the residual chemical shift observed for water nuclei (1H, 2H, and 17O) is due to significant water-macromolecular interactions.

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于2010~2013年的繁殖季节,在中国科学院海北高寒草甸生态系统定位站收集了9种青藏高原常见雀形目鸟类的卵,分别进行了反射率测量。测量光谱范围为可见光(400~750 nm)和短波近红外(750~1050 nm)。卵在两个波段光谱的反射率分别是0.066和0.123,二者差异极显著。在可见光范围内,除赭红尾鸲Phoenicurus ochruros的波峰在绿色光范围内,其他物种都在黄色光范围内;在短波近红外范围内,反射率明显分为3个组,以角百灵和小云雀的地面开放巢较高,黄嘴朱顶雀和黄腹柳莺的灌丛巢较低,其他种居中;开放巢及封闭巢的卵反射率在可见光范围无显著差异,但在短波近红外范围有显著差异。我们认为,在青藏高原高寒草甸生态系统中,植被郁闭度低,地面营巢环境不利于巢与卵的遮阳,造成营开放度高的地面巢的鸟卵近红外反射率相对较高,而灌丛巢和封闭巢的雀形目鸟类鸟卵相对较低,但对可见光谱的卵反射率各物种差异不显著。  相似文献   

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An ecosystem is generally sustained by a set of integrated physical elements forming a functional landscape unit—ecotope, which supplies nutrients, microclimate, and exchanges matter and energy with the wider environment. To better predict environmental change effects on ecosystems, particularly in critically sensitive regions such as high altitudes, it is imperative to recognise how their natural landscape heterogeneity works at different scales to shape habitats and sustain biotic communities prior to major changes. We conducted a comprehensive survey of catchment physical, geological and ecological properties of 380 high-altitude lakes and ponds in the axial Pyrenees at a variety of scales, to formulate and test an integrated model encompassing major flows and interactions that drive lake ecosystems. Three composite drivers encompassed most of the variability in lake catchment characteristics. In order of total percentage of variance explained, they were (i) hydrology/hydrodynamics—responsible for type and discharge of inlets/outlets, and for waterbody size; (ii) bedrock geomorphology, summarising geology, slope and fractal order—all dictating vegetation cover of catchment slope and lake shore, and the presence of aquatic vegetation; and (iii) topography, that is, catchment formation type—driving lakes connectivity, and the presence of summer snow deposits. Although driver (i) appeared to be local, (ii) and (iii) showed gradient changes along altitude and latitude. These three drivers differentiated several lake ecotopes based on their landscape similarities. The three-driver model was successfully tested on a riparian vegetation composition dataset, further illustrating the validity and fundamental nature of the concept. The findings inform on the relative contribution of scale-dependent catchment physical elements to lake ecotope and ecosystem formation in high-altitude lakes, which should be considered in any assessment of potentially major deleterious effects due to environmental/climate change.  相似文献   

18.
One of the important assumptions of compositional analysis is that the elemental composition of an artifact reflects the source of the materials used to make it. Thus, pottery from a particular source will be chemically similar to the raw materials from that source. This "commonsense" assumption seems beyond dispute, but the fact that pottery is a mixture of clay, water, and often temper added by the potter, complicates the interpretation of compositional data from ceramics. This article examines the relationship between potters' behavior in obtaining and using raw materials, on the one hand, and the chemical composition of their finished pottery, on the other, by comparing the elemental composition of ethnographic pottery and raw materials from contemporary pottery-making communities in the Valley of Guatemala. The results of this research show that the relationship between pottery and its constituent raw materials is not as obvious as was first supposed. The article concludes with an alternative approach to compositional analysis that is more in line with the realities of real-world pottery production.  相似文献   

19.
The Chemical Origin of Free Radicals in Coffee and Other Beverages   总被引:1,自引:0,他引:1  
Sugars or carbohydrates are identified as the source of free radicals in coffees, ersatz coffees, a number of other food flavouring and colouring agents formed by processes involving heating, and in beers and stouts. The radicals are not derived from phenolic constituents, in contrast to those in wine, and are unlikely to be due solely to the occurrence of Maillard reactions.  相似文献   

20.
G. May  L. L. Chevanton    P. J. Pukkila 《Genetics》1991,128(3):529-538
We report here the molecular cloning of the A43 mating type factor from Coprinus cinereus, a basidiomycetous fungus. Our molecular analyses revealed an unexpected source of variation in the A factor. Though genetic studies have demonstrated that A has two subunits, alpha and beta, we located three nonoverlapping fragments in the A43 region that have A factor function following DNA-mediated transformation. The three fragments demonstrate no similarity to one another as judged by restriction enzyme maps and by hybridization on Southern blots. We conclude that the A43 factor is composed of at least three subunits. When strains carrying different A factors are examined by hybridization to the cloned subunits, extensive polymorphism is seen. Both intensity of hybridization and restriction fragment lengths vary between strains. Some strains fail to show any hybridization to a probe. In contrast, other strains from widely separated geographic locations apparently share very similar subunits. From comparative restriction enzyme mapping of A43 and a mutated A43 factor, we inferred that a 12-kb deletion in the A factor was responsible for the constitutive, dominant phenotype of the mutated A factor. The results of transformation experiments support an activator model for the activity of the A factor in regulating the A pathway.  相似文献   

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