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排序方式: 共有296条查询结果,搜索用时 484 毫秒
161.
162.
Joron M Frezal L Jones RT Chamberlain NL Lee SF Haag CR Whibley A Becuwe M Baxter SW Ferguson L Wilkinson PA Salazar C Davidson C Clark R Quail MA Beasley H Glithero R Lloyd C Sims S Jones MC Rogers J Jiggins CD ffrench-Constant RH 《Nature》2011,477(7363):203-206
Supergenes are tight clusters of loci that facilitate the co-segregation of adaptive variation, providing integrated control of complex adaptive phenotypes. Polymorphic supergenes, in which specific combinations of traits are maintained within a single population, were first described for 'pin' and 'thrum' floral types in Primula and Fagopyrum, but classic examples are also found in insect mimicry and snail morphology. Understanding the evolutionary mechanisms that generate these co-adapted gene sets, as well as the mode of limiting the production of unfit recombinant forms, remains a substantial challenge. Here we show that individual wing-pattern morphs in the polymorphic mimetic butterfly Heliconius numata are associated with different genomic rearrangements at the supergene locus P. These rearrangements tighten the genetic linkage between at least two colour-pattern loci that are known to recombine in closely related species, with complete suppression of recombination being observed in experimental crosses across a 400-kilobase interval containing at least 18 genes. In natural populations, notable patterns of linkage disequilibrium (LD) are observed across the entire P region. The resulting divergent haplotype clades and inversion breakpoints are found in complete association with wing-pattern morphs. Our results indicate that allelic combinations at known wing-patterning loci have become locked together in a polymorphic rearrangement at the P locus, forming a supergene that acts as a simple switch between complex adaptive phenotypes found in sympatry. These findings highlight how genomic rearrangements can have a central role in the coexistence of adaptive phenotypes involving several genes acting in concert, by locally limiting recombination and gene flow. 相似文献
163.
164.
The developmental transcriptome of Drosophila melanogaster 总被引:2,自引:0,他引:2
Graveley BR Brooks AN Carlson JW Duff MO Landolin JM Yang L Artieri CG van Baren MJ Boley N Booth BW Brown JB Cherbas L Davis CA Dobin A Li R Lin W Malone JH Mattiuzzo NR Miller D Sturgill D Tuch BB Zaleski C Zhang D Blanchette M Dudoit S Eads B Green RE Hammonds A Jiang L Kapranov P Langton L Perrimon N Sandler JE Wan KH Willingham A Zhang Y Zou Y Andrews J Bickel PJ Brenner SE Brent MR Cherbas P Gingeras TR Hoskins RA Kaufman TC Oliver B Celniker SE 《Nature》2011,471(7339):473-479
165.
McLellan JS Pancera M Carrico C Gorman J Julien JP Khayat R Louder R Pejchal R Sastry M Dai K O'Dell S Patel N Shahzad-ul-Hussan S Yang Y Zhang B Zhou T Zhu J Boyington JC Chuang GY Diwanji D Georgiev I Kwon YD Lee D Louder MK Moquin S Schmidt SD Yang ZY Bonsignori M Crump JA Kapiga SH Sam NE Haynes BF Burton DR Koff WC Walker LM Phogat S Wyatt R Orwenyo J Wang LX Arthos J Bewley CA Mascola JR Nabel GJ Schief WR Ward AB Wilson IA Kwong PD 《Nature》2011,480(7377):336-343
Variable regions 1 and 2 (V1/V2) of human immunodeficiency virus-1 (HIV-1) gp120 envelope glycoprotein are critical for viral evasion of antibody neutralization, and are themselves protected by extraordinary sequence diversity and N-linked glycosylation. Human antibodies such as PG9 nonetheless engage V1/V2 and neutralize 80% of HIV-1 isolates. Here we report the structure of V1/V2 in complex with PG9. V1/V2 forms a four-stranded β-sheet domain, in which sequence diversity and glycosylation are largely segregated to strand-connecting loops. PG9 recognition involves electrostatic, sequence-independent and glycan interactions: the latter account for over half the interactive surface but are of sufficiently weak affinity to avoid autoreactivity. The structures of V1/V2-directed antibodies CH04 and PGT145 indicate that they share a common mode of glycan penetration by extended anionic loops. In addition to structurally defining V1/V2, the results thus identify a paradigm of antibody recognition for highly glycosylated antigens, which-with PG9-involves a site of vulnerability comprising just two glycans and a strand. 相似文献
166.
Catalytic activity of the caspase-8-FLIP(L) complex inhibits RIPK3-dependent necrosis 总被引:4,自引:0,他引:4
Oberst A Dillon CP Weinlich R McCormick LL Fitzgerald P Pop C Hakem R Salvesen GS Green DR 《Nature》2011,471(7338):363-367
Caspase-8 has two opposing biological functions--it promotes cell death by triggering the extrinsic pathway of apoptosis, but also has a survival activity, as it is required for embryonic development, T-lymphocyte activation, and resistance to necrosis induced by tumour necrosis factor-α (TNF-α) and related family ligands. Here we show that development of caspase-8-deficient mice is completely rescued by ablation of receptor interacting protein kinase-3 (RIPK3). Adult animals lacking both caspase-8 and RIPK3 display a progressive lymphoaccumulative disease resembling that seen with defects in CD95 or CD95-ligand (also known as FAS and FASLG, respectively), and resist the lethal effects of CD95 ligation in vivo. We have found that caspase-8 prevents RIPK3-dependent necrosis without inducing apoptosis by functioning in a proteolytically active complex with FLICE-like inhibitory protein long (FLIP(L), also known as CFLAR), and this complex is required for the protective function. 相似文献
167.
Dan Lindholm Beat C. Bornhauser Laura Korhonen 《Cellular and molecular life sciences : CMLS》2009,66(21):3399-3402
High blood low-density-lipoprotein (LDL) cholesterol is a serious health problem among an increased number of patients in
the Western world. Statins and other cholesterol lowering drugs have proven to be beneficial as therapy but are not optimal
and show adverse effects in some patients. The LDL receptor is a crucial determinant of cholesterol metabolism in the body
and amenable for drug interventions. Novel insights into the physiology of this receptor come from studies on the ubiquitination
and degradation of LDL receptor by the ubiquitin ligase Mylip/Idol that is induced in cells by the nuclear receptor, LXR.
This may open up new possibilities in the future to influence LDL receptor levels and cholesterol metabolism pharmacologically
in various diseases. 相似文献
168.
The diatom flora of Cowboy Hot Spring, Mono County, California, was studied. Two habitats, one at 37C and one at 41C, were examined. Fifty-six taxa were identified from our samples. These taxa were mostly broadly distributed forms, and no endemic species were encountered. The dominant taxon was Nitzschia frustulum, followed by Achnanthes gibberula, Achnanthes exigua, Nitzschia hantzschiana , and Navicula cincta . 相似文献
169.
By the middle of the nineteenth century, the opinion of science, as well as of philosophy and even religion, was, at least in Britain, firmly in the camp of the plurality of worlds, the view that intelligent life exists on other celestial bodies. William Whewell, considered an expert on science, philosophy and religion (among other areas), would have been expected to support this position. Yet he surprised everyone in 1853 by publishing a work arguing strongly against the plurality view. This was even stranger given that he had endorsed pluralism twenty years earlier in his contribution to the Bridgewater Treatises. In this paper I show that the shift in Whewell’s view was motivated by three factors: the influence of Richard Owen’s theory of archetypes on Whewell’s view of the argument from design, and Whewell’s perception of the need to strengthen such arguments in light of evolutionary accounts of human origins; important developments in his view of philosophy and his role as a scientific expert; and new findings in astronomy. An examination of the development of Whewell’s position provides a lens through which we can view the interplay of theology, philosophy and science in the plurality of worlds debate. 相似文献
170.
Deciphering the evolution and metabolism of an anammox bacterium from a community genome 总被引:15,自引:0,他引:15
Strous M Pelletier E Mangenot S Rattei T Lehner A Taylor MW Horn M Daims H Bartol-Mavel D Wincker P Barbe V Fonknechten N Vallenet D Segurens B Schenowitz-Truong C Médigue C Collingro A Snel B Dutilh BE Op den Camp HJ van der Drift C Cirpus I van de Pas-Schoonen KT Harhangi HR van Niftrik L Schmid M Keltjens J van de Vossenberg J Kartal B Meier H Frishman D Huynen MA Mewes HW Weissenbach J Jetten MS Wagner M Le Paslier D 《Nature》2006,440(7085):790-794
Anaerobic ammonium oxidation (anammox) has become a main focus in oceanography and wastewater treatment. It is also the nitrogen cycle's major remaining biochemical enigma. Among its features, the occurrence of hydrazine as a free intermediate of catabolism, the biosynthesis of ladderane lipids and the role of cytoplasm differentiation are unique in biology. Here we use environmental genomics--the reconstruction of genomic data directly from the environment--to assemble the genome of the uncultured anammox bacterium Kuenenia stuttgartiensis from a complex bioreactor community. The genome data illuminate the evolutionary history of the Planctomycetes and allow us to expose the genetic blueprint of the organism's special properties. Most significantly, we identified candidate genes responsible for ladderane biosynthesis and biological hydrazine metabolism, and discovered unexpected metabolic versatility. 相似文献