分子诊断学概论

分子診斷學概論第一章綜說overview疾病發生原因的影響層次DNA、RNA或蛋白質分子診斷的目的偵測這些致病因子是那個層次發生變化本書著重DNA、RNA的變化蛋白質層次由原文書章節提供TheApplicationofProteomicsToDiseaseDiagnostics遺傳分子的基礎生物巨分子：DNA、RNA、蛋白質、糖類、脂質遺傳物質DNA的發現1928格里夫茲(Griffith)肺炎雙球菌轉形試驗1942艾佛瑞(Avery)研究格里夫茲轉形的物質為何?1952赫希-卻斯(Hershey-Chase)以放射線標示噬菌體的蛋白質（S35）和DNA（P32），感染大腸桿菌的實驗1953雙螺旋結構的發現2003人類基因體計畫的完成參考資料：~cmallery/150/gene/sf11x1b.jpg參考資料：~cmallery/150/gene/sf11x1b.jpg參考資料：Presentedhereisagenomesequenceofanindividualhuman.Itwasproducedfrom~32millionrandomDNAfragments,sequencedbySangerdideoxytechnologyandassembledinto4,528scaffolds,comprising2,810millionbases(Mb)ofcontiguoussequencewithapproximately7.5-foldcoverageforanygivenregion.WedevelopedamodifiedversionoftheCeleraassemblertofacilitatetheidentificationandcomparisonofalternatealleleswithinthisindividualdiploidgenome.ComparisonofthisgenomeandtheNationalCenterforBiotechnologyInformationhumanreferenceassemblyrevealedmorethan4.1millionDNAvariants,encompassing12.3Mb.Thesevariants(ofwhich1,288,319werenovel)included3,213,401singlenucleotidepolymorphisms(SNPs),53,823blocksubstitutions(2–206bp),292,102heterozygousinsertion/deletionevents(indels)(1–571bp),559,473homozygousindels(1–82,711bp),90inversions,aswellasnumeroussegmentalduplicationsandcopynumbervariationregions.Non-SNPDNAvariationaccountsfor22%ofalleventsidentifiedinthedonor,howevertheyinvolve74%ofallvariantbases.Thissuggestsanimportantrolefornon-SNPgeneticalterationsindefiningthediploidgenomestructure.Moreover,44%ofgeneswereheterozygousforoneormorevariants.Usinganovelhaplotypeassemblystrategy,wewereabletospan1.5Gbofgenomesequenceinsegments.200kb,providingfurtherprecisiontothediploidnatureofthegenome.Thesedatadepictadefinitivemolecularportraitofadiploidhumangenomethatprovidesastartingpointforfuturegenomecomparisonsandenablesaneraofindividualizedgenomicinformation.AuthorSummaryWehavegeneratedanindependentlyassembleddiploidhumangenomicDNAsequencefrombothchromosomesofasingleindividual(J.CraigVenter).Ourapproach,basedonwhole-genomeshotgunsequencingandusingenhancedgenomeassemblystrategiesandsoftware,generatedanassembledgenomeoverhalfofwhichisrepresentedinlargediploidsegments(.200kilobases),enablingstudyofthediploidgenome.Comparisonwithpreviousreferencehumangenomesequences,whichwerecompositescomprisingmultiplehumans,revealedthatthemajorityofgenomicalterationsarethewell-studiedclassofvariantsbasedonsinglenucleotides(SNPs).However,theresultsalsorevealthatlesserstudiedgenomicvariants,insertionsanddeletions,whilecomprisingaminority(22%)ofgenomicvariationevents,actuallyaccountforalmost74%ofvariantnucleotides.Inclusionofinsertionanddeletiongeneticvariationintoourestimatesofinterchromosomaldifferencerevealsthatonly99.5%similarityexistsbetweenthetwochromosomalcopiesofanindividualandthatgeneticvariationbetweentwoindividualsisasmuchasfivetimeshigherthanpreviouslyestimated.Theexistenceofawell-characterizeddiploidhumangenomesequenceprovidesastartingpointforfutureindividualgenomecomparisonsandenablestheemergingeraofindividualizedgenomicinformation.Identificationandanalysisoffunctionalelementsin1%ofthehumangenomebytheENCODEpilotproject.Nature.2007Jun14;447(7146):799-816TheEncyclopediaofDNAElements(ENCODE)Projectprovideamorebiologicallyinformativerepresentationofthehumangenomebyusinghigh-throughputmethodstoidentifyandcataloguethefunctionalelementsencoded.First,ourstudiesprovideconvincingevidencethatthegenomeispervasivelytranscribed,suchthatthemajorityofitsbasescanbefoundinprimarytranscripts,includingnon-protein-codingtranscripts,andthosethatextensivelyoverlaponeanother.Second,systematicexaminationoftranscriptionalregulationhasyieldednewunderstandingabouttranscriptionstartsites,includingtheirrelationshiptospecificregulatorysequencesandfeaturesofchromatinaccessibilityandhistonemodification.Third,amoresophisticatedviewofchromatinstructurehasemerged,includingitsinter-relationshipwithDNAreplicationandtranscriptionalregulation.Finally,integrationofthesenewsourcesofinformation,inparticularwithrespecttomammalianevolutionbasedoninter-andintra-speciessequencecomparisons,hasyieldednewmechanisticandevolutionaryinsightsconcerningthefunctionallandscapeofthehumangenome.Together,thesestudiesaredefiningapathforpursuitofamorecomprehensivecharacterizationofhumangenomefunction.ThehighlightsofourfindingstodateincludeThehumangenomeispervasivelytranscribed,suchthatthemajorityofitsbasesareassociatedwithatleastoneprimarytranscriptandmanytranscriptslinkdistalregionstoestablishedprotein-codingloci.Manynovelnon-protein-codingtranscriptshavebeenidentified,withmanyoftheseoverlappingprotein-codinglociandotherslocatedinregionsofthegenomepreviouslythoughttobetranscriptionallysilent.Numerouspreviouslyunrecognizedtranscriptionstartsiteshavebeenidentified,manyofwhichshowchromatinstructureandsequence-specificprotein-bindingpropertiessimilartowell-understoodpromoters.Regulatorysequencesthatsurroundtranscriptionstartsites