简介:摘要目的讨论DNA鉴定结果探究。方法查阅文献资料并结合个人经验进行归纳总结。结论如果办案人员不能正确理解DNA鉴定结论的概率性含义,尤其是不能正确区分三种不同类型的DNA鉴定结论,就可能会对案件事实作出错误的认定。对此,法医学学者指出“关于线粒体DNA鉴定结论,不同的实验室可能会有不同的表述……这些结论的理解对侦查和判案有重要的影响,理解偏颇会将案件向错误方向引导。
简介:DNAisthegeneticmaterialofvariousorganisms.ExtracellularDNAadsorbedorboundonsurface-activeparticlesinsoilshasbeenshowntopersistforlongperiodsagainstnucleasesdegradationandstillretaintheabilitytotransformcompetentcells.ThispaperreviewssomerecentadvancesonthebindingandtransformationofextracellularDNAinsoils,whichisfundamentaltounderstandingthenatureofthesoil,regulatingbiodiversity,andassessingtheriskofreleasinggeneticallyengineeredmicroorganisms(GEMs)aswellasbeinghelpfulfordevelopmentofthegeneticevolutionaltheoryofbacteria.Severalinfluencingfactors,suchassoilpH,ionicstrength,soilsurfaceproperties,andcharacteristicsoftheDNApolymer,arediscussed.Todate,theunderstandingofthetypeofmolecularbindingsitesandtheconformationofadsorbedandboundDNAtosoilparticlesisstillinitsinfancy.
简介:Colorectalcarcinoma(CRC)isacommoncauseofmorbidityandmortalityworldwide.TwopathogenicpathwaysareinvolvedinthedevelopmentofadenomatoCRC.ThefirstpathwayinvolvesAPC/β-catenincharacterizedbychromosomalinstabilityresultingintheaccumulationofmutations.ThesecondpathwayischaracterizedbylesionsinDNAmismatchrepairgenes.AberrantDNAmethylationinselectedgenepromotershasemergedasanewepigeneticpathwayinCRCdevelopment.CRCscreeningisthemostefficientstrategytoreducedeath.SpecificDNAmethylationeventsoccurinmultistepcarcinogenesis.EpigeneticgenesilencingisacausativefactorofCRCdevelopment.DNAmethylationshavebeenextensivelyexaminedinstoolfromCRCandprecursorlesions.ManymethylatedgeneshavebeendescribedinCRCandadenoma,althoughnodefiniteDNAmethylationbiomarkerspanelhasbeenestablished.MultipleDNAmethylationbiomarkers,includingsecretedfrizzled-relatedprotein2,secretedfrizzled-relatedprotein1,tissuefactorpathwayinhibitor2,vimentin,andmethylguanineDNAmethyltransferase,havebeenfurtherinvestigated,andobservationshaverevealedthatDNAmethylationbiomarkersexhibitwithhighsensitivityandspecificity.ThesemarkersmayalsobeusedtodiagnoseCRCandadenomainearlystages.Realtimepolymerasechainreaction(qPCR)issensitive,scalable,specific,reliable,timesaving,andcosteffective.Stoolexfoliatedmarkersprovideadvantages,includingsensitivityandspecificity.AstoolqPCRmethylationtestmayalsobeanenhancedtoolforCRCandadenomascreening.
简介:目的研究DNAIQ磁珠法结合MaxwellTM16自动仪对接触DNA提取的应用价值。方法151份案件接触DNA检材95℃裂解后,采用DNAIQ磁珠法结合MaxwellTM16自动仪提取DNA,然后进行DNA定量和STR分型检测,统计各种类型的接触DNA含量I、PCCT值和STR分型成功率。结果151份案件接触DNA检材中,除果核平均DNA获得量为9.51ng以外,其它接触检材的平均DNA获得量均大于10ng,烟蒂检验成功率最高为93%,果核检验成功率较低,为60%。所有DNA样品的IPCCT值均在27左右,纯度高。结论大部分接触DNA检材采用DNAIQ磁珠法结合MaxwellTM16自动仪可提取到足以进行STR分型的DNA。