生物科学总论
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Q生物科学总论 200810401 0 生命之树的原核枝… 一组分矢量方法的贡献=Prokary— otic branch of the rl1ree of Life:A composition vector approachl英J/郝柏林(T L fe Research Center Fudan Univm‘sity Shanghai 200433;China),高雷//植物分类学 报.一2008,46(3).一258~262 The Cornposition Vectol’ I、‘ee(CVTree)is a parameter— fi-ce and alignrnent--仟ce method to infer prokaryotic phy— Iogeny frOm theil‘complete genomes.It is distinct fTom the tl’ad tiOlla1 l 6S rRNA ana1ysis in both the input data and the methodology.The prokal‘yotic phylogenetic trees COIl— structed by using the CV_rI.ee method agl‘ee WeI1 with the Bel’gey’s taxonomy 11]all majol’gl‘oupings and fine branch— ilag pattel’IIS Th LIS.conlbined LISe of tile CVT1‘ce approach and the】6S l’RNA allaIVSiS may provide an ob1ect ve and rel!able reconstl‘uction ot’the pl‘okra’yotic bl‘anch of the Tree of1 j佗. 1参23 O11 20O810401 1 真核生物s M c基因家族中拷贝数目的长期稳定进 化爿 ong—term maintenance of stable copy nuinber in the eukaryotic SMC famih,:origin of a vertebrate meiotic SMC1 and fate of recent segmental duplicates[英]/Surcel A ’he In!el’co1]ege G1’aduate P1‘ogram in Cetl and Develop— nlental 13ielogy,The I Iuck hastjtufts of the I 1fc Sc ences、 The Pennsvlvallia State 1.311ivel’s1tv,UniVeFSity Pal’k PA 1 6802:【 SA),Zou Xiaofan…//植物分类学报.一2008,46 (3).一405 ̄423 Membei’s ot’the St;‘uctul‘al Maintenance of Chromo— SOrtie(SMC) rfii1Y have Iong been ofjnterest to meleculal‘ and evelutional‘Y bio1ogj sis fbl‘the!r re1e in chromosome sn‘uctu!’al d3manlics.particulal’ly sistcl—chromatid cohesion. CODdensation.an(i l)NA 1.epaii’.SMC and 1.olatcd protejns arc found in al1 majO1 gl’oups of living el’gani snls and share a COITInlon stl‘LICtUl’e ot’conSC1’ved N and C globulal’domains sepal’ated fiom the COflSC[’ved hingc domain by long coiled—— coil regions.In eukaryotes thel’e are six paralogous pi’oteins that form!hi’ee hetel’odimel’ic pairs whereas in prokaryotes there is 011lY one SMC protein that homed!mel’izes.From IIeccntly completed genome sequences,we have identifled SMC genes fi’om 34 ellkal‘yotes that have not been de— SCl‘ibed in pl‘evieLlS reports.Our phylogenetic analysts of these and pl’c、 !oustY!dent!fied SMC genes supports an origin FOl the vertebt ate meiotic SMC 1 in the most recent common ancestol‘sinee the divergence from jnvertebrate alli1"11a1s Additional1Y.we have dentifled dupljcate copies due to segreenta1 duPl1cations for some of the SMC pal alogs in plants and yeast,mainly SMC2 and SMC6,and detected evidence that dup1icares ot’ethel‘para1ogs were lost,suggesting diffel‘ential evolution for these genes.Oul’ analysis indicates thai the SMC pal’alogs have been stab1y maintained at、,e1.v IOW copy numbers.even aflel。segmentaI (genome—wide)duplications.It j s possihie that such IOW copy numbel‘s might be selected during cukaryotic evolution, although ethel‘possibilities al‘e not ruled out.图1 0表3参45 Ql3 20081 0401 2 高时空分辨的脑功能光学成像研究进展=Progress 0n optical imaging of functional brain with high temporal and spatial resolution/王珍(华中科技火学生命科学与技术学 院.湖北,武汉430074),刘庆茕//生物化学与生物物理进 展.一2008,35(5)一488 ̄495 脑功能成像技术对深入分析脑的信息加工过程,揭示 脑的高级功能至关重要,是同前国际石)『究热点,已经在{Ij1经 科学研究和神经系统疾病的临床诊断方面取得_r很大的 进展。已有腑功能成像技术如:功能磁共振成像 (fMRI)、正}乜子断层成像(1’ ’)、脑电 (1-;EG)、腑磁 (M EG)等等,虽然已被成功Jf』】:腑功能研究,但是I {哺这 些方法也存在着nCtll或空问分辨率不够的局限。比较 f 言,光学成像方法表现 其独特魅力。激光散斑衬比成 像和内源信号光学成像由f能提供空问取样、【Ilj问分辨 率及空间分辨率三者的最佳组合和不需加入外源性标记 物等特点,与其他脑功能成像技术相比其优势可能更为突 出。具有较高的时间和空间分辨率的这两种J】f{i功能光学 成像技术及其应用都取得_r亟大发展,成为研究脑皮层功 能构筑和脑病理生删的有力工具。但是目前这两种成像 方法也面临着一些挑战。表2参36 el9 20081 0401 3 类群取样与系统发育分析精确度之探索一 l1axOn saHi— piing and Ihe accuracy of’ph),Iogenetic analyses]英}/I!call1 r A(Section of Integ ̄‘at!ve Biology and Centel‘fbl‘Col1lpu— tational Bielegy and Bioinfo ̄’matics.One Unive1.sity Sta— tion(20930, Fhe UniversityofTexas,Austin, rX 7871 2;USA), Hedtke S M…//植物分类学报.一2008,46(3).一23%257 Appropriate and extensive taxon sampling is one of tile most impol lant delta’minants el、accul’ate phylogel ̄etic estimation.In addition accul‘acy ot‘infel‘ences about eve— hltionary pl’ocesses obtained仔om phylogenetic analyses is improved significantlY by thol ough taxon sarnpl1ng efforts.Many 1’ecent efforts to improve phylogenctiC est卜 mates have focused instead on increasing sequence length or the nunlbel‘OfOVCI’all charactel’s in the analysis,and this often does have a beneficial effect on the accuracy of phy— Iogenetic analyses.flowevei ,phytogenetic analyses of few taxa(but each 1’epresented by many chin actel‘s)can be sub— ject to stl’ong systematic biases,which in tlirn produce higi1 measul’es of 1.epeatability(such as I)oolstl’ap pl‘oportions) in support of incorrect or misleading phylogenetic 1.csults. Thus,it is important for phylogenetic sts to consider both the sampling of taxa.as welj as tile samptin2 ofchal actcl‘s, in designing phylogenetic studies.Taxon sampling also improves estimates ofevolutionary pal‘ametel’s del‘Ned ’om phylogenetic trees.and is thus important r()r impI‘eyed ap— plications of phylogenetic analyses.Analysis of scnsith ity