共查询到20条相似文献,搜索用时 15 毫秒
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FLIES AND FLOWERS IN DARWIN'S RACE 总被引:2,自引:0,他引:2
Anton Pauw Jaco Stofberg Richard J. Waterman 《Evolution; international journal of organic evolution》2009,63(1):268-279
The idea of coevolution originated with Darwin's proposal that long-proboscid pollinators and long-tubed flowers might be engaged in reciprocal selection, but this has not been demonstrated. Here we test key aspects of Darwin's hypothesis of reciprocal selection in an experiment with naturally interacting populations of extremely long-proboscid flies ( Moegistorhynchus longirostris : Nemestinidae) and long-tubed irises ( Lapeirousia anceps : Iridaceae). We show that the benefit derived by both the fly (volume of nectar consumed) and the plant (number pollen grains received) depends on the relative length of their interacting organs. Each trait is shown to act both as agent and target in directional reciprocal selection, potentially leading to a race. This understanding of how fitness in both species varies in relation to the balance of their armament allows us to make tentative predictions about the nature of selection across multiple communities. We find that in each community a core group of long-tubed plant species might together be involved in diffuse coevolution with the fly. In poorly matched populations, the imbalance in armament is too great to allow reciprocal selection to act, and these species might instead experience one-sided selection that leads to convergence with the core species. Reciprocal selection drives the evolution of the community, then, additional species become attached to the network of interacting mutualists by convergence. 相似文献
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Kawachi R Koike Y Watanabe Y Nishio T Sakuda S Nagasawa H Oku T 《Molecular biotechnology》2004,27(3):179-186
This article describes a simple method for accurate rapid amplification of complementary deoxyribonucleic acid (cDNA) ends
(RACE), the distinctive feature being that only a gene-specific primer is used, without an anchor or adapter primer. Under
these conditions, Thermus aquaticus (Taq) polymerase synthesizes cDNA ends exactly, so that amplified products obtain a characteristic structure: a terminal inverted
repeat composed of a gene-specific primer and occasionally several nucleotides from its 3′ flanking sequence. These structures
suggest a hypothetical mechanism of cDNA end synthesis in which Taq DNA polymerase synthesizes a sequence complementary to the gene-specific primer at the 3′ end of the daughter strand by switching
the template to the 5′ terminal region through circularization of the DNA. As a result, the targeted cDNA will be efficiently
amplified with only a single gene-specific primer. This technique, which provides highly specific amplification of the 5′
and 3′ ends of a cDNA, is especially useful for isolation of cDNA when the corresponding messenger ribonucleic acid is scarce. 相似文献
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John Solomos 《Ethnic and racial studies》2013,36(1):231-232
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SØREN HOLM 《Developing world bioethics》2008,8(2):82-88
This paper discusses the link between pharmacogenetics and race, and the global justice issues that the introduction of pharmacogenetics in pharmaceutical research and clinical practice will raise. First, it briefly outlines the likely impact of pharmacogenetics on pharmaceutical research and clinical practice within the next five to ten years and then explores the link between pharmacogenetic traits and ‘race’. It is shown that any link between apparent race and pharmacogenetics is problematic and that race cannot be used as a proxy for pharmacogenetic knowledge. The final section considers the implications of the development of pharmacogenetics for health care systems in low‐ and middle‐income countries. 相似文献
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RACE技术研究进展与展望 总被引:3,自引:1,他引:2
近年来,RACE(rapid amplification of cDNA ends)技术,即cDNA末端快速扩增技术,是一种快速扩增cDNA的5′和3′末端的有效方法,在扩增全长cDNA方面得到了广泛的应用。综述了RACE技术的研究进展,总结了优化RACE技术几个关键环节。最后展望了RACE技术的发展。 相似文献
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J. R. KANTOR 《American anthropologist》1925,27(2):267-283
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目的:为筛选和克隆大乳头水螅发育调控相关基因的全长cDNA,构建大乳头水螅RACE cDNA文库.方法:提取大乳头水螅总RNA后从其中分离mRNA,运用SMART技术构建RACE cDNA文库.为鉴定所构建文库的质量,根据GenBank中大乳头水螅actin基因cDNA序列设计5'RACE和3'RACE的引物及用于扩增actin基因编码区全长序列的引物.结果:琼脂糖凝胶电泳结果表明,RACE cDNA文库中全长cDNA的长度集中在500-2 000bp之间.5'RACE、3'RACE PCR及扩增actin基因编码区全长序列时均以本文构建的大乳头水螅RACE cDNA文库为模板,这3个PCR反应均能扩增出产物,产物大小与目标片段预计大小相似.PCR产物分别经T/A克隆及测序后证明为大乳头水螅actin基因cDNA的相应序列.结论:RACE cDNA文库的成功构建为通过RACE方法获得大乳头水螅功能基因cDNA全长序列奠定了基础. 相似文献
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5' end cDNA amplification using classic RACE 总被引:1,自引:0,他引:1
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Having knowledge of the entire 3' sequence of a cDNA is often important because the non-coding terminal region can contain signals that regulate the stability or subcellular localization of the mRNA. Also, some messages use alternative genomic sites for cleavage and polyadenylation that can alter the above properties, or change the encoded protein. Full-length cDNAs can be obtained from complex mixtures of cellular mRNA using rapid amplification of cDNA ends (RACE) PCR as long as part of the mRNA sequence is known; adding non-specific tags to the ends of the cDNA allows the regions between the known parts of the sequence and the ends to be amplified. In 3' RACE, the poly(A) tail functions as a non-specific tag at the 3' end of the mRNA. cDNA ends can be obtained in 1-3 days using this protocol. 相似文献
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Vicki Harman 《Ethnic and racial studies》2013,36(12):2218-2219