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排序方式: 共有86条查询结果,搜索用时 15 毫秒
31.
32.
Languages, like molecules, document evolutionary history. Darwin observed that evolutionary change in languages greatly resembled the processes of biological evolution: inheritance from a common ancestor and convergent evolution operate in both. Despite many suggestions, few attempts have been made to apply the phylogenetic methods used in biology to linguistic data. Here we report a parsimony analysis of a large language data set. We use this analysis to test competing hypotheses--the "express-train" and the "entangled-bank" models--for the colonization of the Pacific by Austronesian-speaking peoples. The parsimony analysis of a matrix of 77 Austronesian languages with 5,185 lexical items produced a single most-parsimonious tree. The express-train model was converted into an ordered geographical character and mapped onto the language tree. We found that the topology of the language tree was highly compatible with the express-train model. 相似文献
33.
Chin K de Solorzano CO Knowles D Jones A Chou W Rodriguez EG Kuo WL Ljung BM Chew K Myambo K Miranda M Krig S Garbe J Stampfer M Yaswen P Gray JW Lockett SJ 《Nature genetics》2004,36(9):984-988
Transition through telomere crisis is thought to be a crucial event in the development of most breast carcinomas. Our goal in this study was to determine where this occurs in the context of histologically defined breast cancer progression. To this end, we assessed genome instability (using fluorescence in situ hybridization) and other features associated with telomere crisis in normal ductal epithelium, usual ductal hyperplasia, ductal carcinoma in situ and invasive cancer. We modeled this process in vitro by measuring these same features in human mammary epithelial cell cultures during ZNF217-mediated transition through telomere crisis and immortalization. Taken together, the data suggest that transition through telomere crisis and immortalization in breast cancer occurs during progression from usual ductal hyperplasia to ductal carcinoma in situ. 相似文献
34.
Tomlinson IP Webb E Carvajal-Carmona L Broderick P Howarth K Pittman AM Spain S Lubbe S Walther A Sullivan K Jaeger E Fielding S Rowan A Vijayakrishnan J Domingo E Chandler I Kemp Z Qureshi M Farrington SM Tenesa A Prendergast JG Barnetson RA Penegar S Barclay E Wood W Martin L Gorman M Thomas H Peto J Bishop DT Gray R Maher ER Lucassen A Kerr D Evans DG;CORGI Consortium Schafmayer C Buch S Völzke H Hampe J Schreiber S John U Koessler T Pharoah P van Wezel T Morreau H Wijnen JT Hopper JL 《Nature genetics》2008,40(5):623-630
To identify colorectal cancer (CRC) susceptibility alleles, we conducted a genome-wide association study. In phase 1, we genotyped 550,163 tagSNPs in 940 familial colorectal tumor cases (627 CRC, 313 high-risk adenoma) and 965 controls. In phase 2, we genotyped 42,708 selected SNPs in 2,873 CRC cases and 2,871 controls. In phase 3, we evaluated 11 SNPs showing association at P < 10(-4) in a joint analysis of phases 1 and 2 in 4,287 CRC cases and 3,743 controls. Two SNPs were taken forward to phase 4 genotyping (10,731 CRC cases and 10,961 controls from eight centers). In addition to the previously reported 8q24, 15q13 and 18q21 CRC risk loci, we identified two previously unreported associations: rs10795668, located at 10p14 (P = 2.5 x 10(-13) overall; P = 6.9 x 10(-12) replication), and rs16892766, at 8q23.3 (P = 3.3 x 10(-18) overall; P = 9.6 x 10(-17) replication), which tags a plausible causative gene, EIF3H. These data provide further evidence for the 'common-disease common-variant' model of CRC predisposition. 相似文献
35.
Quantitative mapping of amplicon structure by array CGH identifies CYP24 as a candidate oncogene 总被引:21,自引:0,他引:21
Albertson DG Ylstra B Segraves R Collins C Dairkee SH Kowbel D Kuo WL Gray JW Pinkel D 《Nature genetics》2000,25(2):144-146
We show here that quantitative measurement of DNA copy number across amplified regions using array comparative genomic hybridization (CGH) may facilitate oncogene identification by providing precise information on the locations of both amplicon boundaries and amplification maxima. Using this analytical capability, we resolved two regions of amplification within an approximately 2-Mb region of recurrent aberration at 20q13.2 in breast cancer. The putative oncogene ZNF217 (ref. 5) mapped to one peak, and CYP24 (encoding vitamin D 24 hydroxylase), whose overexpression is likely to lead to abrogation of growth control mediated by vitamin D, mapped to the other. 相似文献
36.
新的设计方法是用一块MOS LSI芯片将模拟和数字功能合在一起,这样既能降低线性放大器、模-数与数-模转换器和精密频率滤波器这一类电路的成本,缩小其尺寸,又可提高它的可靠性。制作模拟电路的方法与制作如数字逻辑、存储器和微处理器这类 相似文献
37.
Cancer cells have diverse biological capabilities that are conferred by numerous genetic aberrations and epigenetic modifications. Today's powerful technologies are enabling these changes to the genome to be catalogued in detail. Tomorrow is likely to bring a complete atlas of the reversible and irreversible alterations that occur in individual cancers. The challenge now is to work out which molecular abnormalities contribute to cancer and which are simply 'noise' at the genomic and epigenomic levels. Distinguishing between these will aid in understanding how the aberrations in a cancer cell collaborate to drive pathophysiology. Past successes in converting information from genomic discoveries into clinical tools provide valuable lessons to guide the translation of emerging insights from the genome into clinical end points that can affect the practice of cancer medicine. 相似文献
38.
Greenman C Stephens P Smith R Dalgliesh GL Hunter C Bignell G Davies H Teague J Butler A Stevens C Edkins S O'Meara S Vastrik I Schmidt EE Avis T Barthorpe S Bhamra G Buck G Choudhury B Clements J Cole J Dicks E Forbes S Gray K Halliday K Harrison R Hills K Hinton J Jenkinson A Jones D Menzies A Mironenko T Perry J Raine K Richardson D Shepherd R Small A Tofts C Varian J Webb T West S Widaa S Yates A Cahill DP Louis DN Goldstraw P Nicholson AG Brasseur F Looijenga L Weber BL Chiew YE DeFazio A 《Nature》2007,446(7132):153-158
Cancers arise owing to mutations in a subset of genes that confer growth advantage. The availability of the human genome sequence led us to propose that systematic resequencing of cancer genomes for mutations would lead to the discovery of many additional cancer genes. Here we report more than 1,000 somatic mutations found in 274 megabases (Mb) of DNA corresponding to the coding exons of 518 protein kinase genes in 210 diverse human cancers. There was substantial variation in the number and pattern of mutations in individual cancers reflecting different exposures, DNA repair defects and cellular origins. Most somatic mutations are likely to be 'passengers' that do not contribute to oncogenesis. However, there was evidence for 'driver' mutations contributing to the development of the cancers studied in approximately 120 genes. Systematic sequencing of cancer genomes therefore reveals the evolutionary diversity of cancers and implicates a larger repertoire of cancer genes than previously anticipated. 相似文献
39.
选用了四组催化体系,并以不同的配比对甲基化短梗霉多糖进行了还原裂解,其产的用GC,IR和NMR进行了分析测试。结果表明,用这四组催化体系对甲基化短梗霉多糖的还原裂解都能得到了予期的产品,当Et3SiH:TMSOMS:BF3OEt2=5:5:1时效果好,同时测定了短梗霉多糖的结构。 相似文献
40.
Corey DP García-Añoveros J Holt JR Kwan KY Lin SY Vollrath MA Amalfitano A Cheung EL Derfler BH Duggan A Géléoc GS Gray PA Hoffman MP Rehm HL Tamasauskas D Zhang DS 《Nature》2004,432(7018):723-730
Mechanical deflection of the sensory hair bundles of receptor cells in the inner ear causes ion channels located at the tips of the bundle to open, thereby initiating the perception of sound. Although some protein constituents of the transduction apparatus are known, the mechanically gated transduction channels have not been identified in higher vertebrates. Here, we investigate TRP (transient receptor potential) ion channels as candidates and find one, TRPA1 (also known as ANKTM1), that meets criteria for the transduction channel. The appearance of TRPA1 messenger RNA expression in hair cell epithelia coincides developmentally with the onset of mechanosensitivity. Antibodies to TRPA1 label hair bundles, especially at their tips, and tip labelling disappears when the transduction apparatus is chemically disrupted. Inhibition of TRPA1 protein expression in zebrafish and mouse inner ears inhibits receptor cell function, as assessed with electrical recording and with accumulation of a channel-permeant fluorescent dye. TRPA1 is probably a component of the transduction channel itself. 相似文献