computational+gene+prediction+by+combining+two+gene+finding+programs

《computational+gene+prediction+by+combining+two+gene+finding+programs》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

1、Chapter2GenePrediction2．1ReviewofBiologicalBackground2．1．1DNAisthecodeoflife．Thenamestemsfromdeoxyribonucleicacidwhichisanucleicacidthatc。ntainsthegeneticinstructi。nsforthedevel。pmentalpr。cess。f1iVing。rganisms·Proteins，whicharethebasis。flife，arec。nstr

2、uctedfr。mDNAbytranscriptionandtranslation．ThestructureofDNAisadoublehelixwheretwostrandswraparoundeachother．Chemically，DNAisamacromoleculecomposedofabackbonemadeofsugarsandphosphategroupsandalongpolymerofsimpleunitscallednucleotideseachofwnlcncontains

3、oneofthefournitrogenousbases．Thefourbasesareadenine(abbreVlatedA)，cytosine(C)，guanine(G)andthymine(T)．Eachsugarhasonebaseattachedtoit·Thebasesoneachstrandarebondedtothebasesontheotherstrandandthat1SthereasonwhyDNAformsadouble．strandedspiral．Asthecanon

4、icalwatson’Cnckbasepairingdescribes，AisbondedtoTandGisbondedtoC．ButNon。Watson-Crickbasepairingalsooccurs．Inaddition，usuallyeachstrandhastwodlfferentends：5’(fiveprime)endand3’(threeprime)end．DNAresidesinalllivingcellsandcontrolsthecellularactivities，su

5、chasgrowth，division,moVement，deathandSOforth．WhenacellneedstoproduceaparticularProteln，aslgnalwillstimulateanenzymetounwindtheDNA．Thenbythetwoprocessesoftranscriptionandtranslation，theDNAisencodedtoproteins．Intranscrlptlon，thetwostrandsofDNAareseparat

6、edandthecodingsequenceononestrandlstranscribedintoamessengerRNA(mRNA)sequence，whichwillactasatemplateforthefurthertransformation．TheonlydifferencebetweenmRNAandDNAISthatithasuracil(U)insteadofthymine(T)，withUbondingtoA．Aftertransc州10n，RNAmovesoutfromt

7、henucleus．Intranslation，bymRNAandtransferRNA(tRNA)，RNApassesitsgeneticmessagestotheoutsideofnucleus．EVerYthreeletterwords(triplets)，calledcodons，aretranslatedintooneaminoacid．Eventuallyaproteinisformedbylinkingsomeoftheaminoacids．4．硕士学位论文2．1．2GenesDNA

8、isaverylongmolecule，howevernotalloftheDNAwillbecomeproteins．GeneswiththegeneticmessageinDNAdeterminewhatanorganismlookslikeandhowitacts．Ageneisalocatableregionofgenomicsequencethatcorrespondstoaunitofinheritance，whichisassociatedwithregulatory