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51.
荷叶铁线蕨自然居群的遗传多样性研究 总被引:6,自引:0,他引:6
荷叶铁线蕨(Adiantumreniformevar. sinense)为我国特有植物,具有重要的经济价值,目前仅分布于重庆的少数地区。近几十年来,由于过度开发,该种的分布范围日益缩小,已处于灭绝的边缘。本研究利用等位酶标记检测了荷叶铁线蕨 6个自然居群共 136个个体的遗传多样性,共检测到了 5个酶系统的 14个位点,获得了 7个多态位点。结果表明:与其他蕨类植物相比,荷叶铁线蕨居群内的遗传多样性水平比较低。平均每位点的有效等位基因数(Ae)为 1. 778,多态位点百分率(P)为 0. 441,期望杂合度(He)为 0. 199,观察杂合度 (Ho)为 0. 235。其居群间的遗传分化也很低,居群间的遗传变异仅占总变异的 1. 49%,而 98. 51%的变异存在于居群内部。采用Hardy Wein berg平衡和固定指数F对荷叶铁线蕨的居群遗传结构进行了分析,结果表明其种群可能是以配子体间异交为主的混合交配体系。导致荷叶铁线蕨濒危的主要原因是生境的破坏以及过度开采所导致的生境片断化使其居群变小、近交率加大、遗传变异趋低,降低了其生存以及进化的潜力。 相似文献
52.
Dumonteil E Ruiz-Piña H Rodriguez-Félix E Barrera-Pérez M Ramirez-Sierra MJ Rabinovich JE Menu F 《Memórias do Instituto Oswaldo Cruz》2004,99(3):253-256
In most countries, Chagas disease transmission control remains based on domestic insecticide application. We thus evaluated the efficacy of intra-domicile cyfluthrin spraying for the control of Triatoma dimidiata, the only Chagas disease vector in the Yucatán peninsula, Mexico, and monitored potential re-infestation every 15 days for up to 9 months. We found that there was a re-infestation of houses by adult bugs starting 4 months after insecticide application, possibly from sylvatic/peridomicile areas. This points out the need to take into account the potential dispersal of sylvatic/peridomestic adult bugs into the domiciles as well as continuity action for an effective vector control. 相似文献
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Rafael Jaime Julio M. Alc ntara Jesú s M. Bastida Pedro J. Rey 《Journal of Plant Ecology》2015,8(5):457
Aims This study explores the patterns of niche differentiation in a group of seven closely related columbines (genus Aquilegia, Ranunculaceae) from the Iberian Peninsula. Populations of these columbines are subject to complex patterns of divergent selection across environments, which partly explain the taxonomic structure of the group. This suggests the hypothesis that niche divergence must have occurred along the process of diversification of the group.Methods We used MaxEnt to build environmental niche models of seven subspecies belonging to the three species of Aquilegia present in the Iberian Peninsula. From these models, we compared the environmental niches through two different approaches: ENMtools and multivariate methods.Important findings MaxEnt distributions conformed closely to the actual distribution of the study taxa. ENMtools methods failed to uncover any clear patterns of niche differentiation or conservatism in Iberian columbines. Multivariate analyses indicate the existence of differentiation along altitudinal gradients and along a gradient of climatic conditions determined by the summer precipitation and temperatures. However, climatic conditions related to winter temperature and precipitation, as well as soil properties, were equally likely to show conservatism or divergence. The complex patterns of niche evolution we found suggest that Iberian Columbines have not been significantly constrained by forces of niche conservatism, so they could respond adaptively to the fast and profound climate changes in the Iberian Peninsula through the glacial cycles of the Pleistocene. 相似文献
59.
Reddy RE Pan Y Johnson DD Chen YY Datwyler SA Hauptman MS Thottathil JK 《Bioorganic & medicinal chemistry》2005,13(10):3467-3473
An efficient method was developed for the preparation of polyanionic affinity agent (3), a key component in the measurement of glycated hemoglobin (GHb). Glycated hemoglobin is an important clinical marker for diagnosis of patients with diabetes and useful to monitor the management of disease. The affinity agent (3) was prepared based on coupling reaction between poly(acrylic acid) (1) and 3-aminophenylboronic acid (2) in water. The critical features of this polymeric affinity agent (3), such as size, boronic acid incorporation ratio and concentration, on the measurement of glycated hemoglobin were evaluated. It was found that the agent (3) prepared using poly(acrylic acid) (1) with 225 kDa molecular weight gave optimal GHb measurement. The performance test results demonstrated that the boronic acid incorporation ratio and concentration of affinity agent (3) play a critical role in the assay and determines the precision of glycated hemoglobin measurement. 相似文献
60.
The spontaneous germinal activation of quiescent Uq transposable elements is reported. Thirty-nine spotted exceptions were observed at a rate of about 2 x 10(-4) from 687 otherwise colorless ears produced from the cross of a-ruq/a-ruq (colorless or occasionally sectored) X an a-ruq tester (colorless). All exceptions had spotting patterns distinct from the pattern of our original standard Uq (Uq1)-a-ruq spotting. From these spotted exceptions five new Uq elements (Uq2, Uq3, Uq4, Uq5 and Uq6) have been isolated. Genetic evidence for the Uq nature of the five germinal isolates is presented. First, each of the five spotted exceptions was homozygous for the a-ruq reporter allele. Second, four new Uq isolates (Uq2, Uq3, Uq4 and Uq5), after being reconstituted into a alpha degrees sh2/alpha degrees sh2 (no Uq) line, could transactivate the standard a-ruq allele and continue to produce their distinct spotting phenotypes. Third, these five new Uqs are also capable of transactivating the c-ruq65 and c-ruq67 alleles. However, the transactivation of c-ruq is generally weaker than that of a-ruq. 相似文献