FTA卡直接扩增缓冲增强剂的研制

目的研制一种能够配合非直接扩增试剂应用的PCR缓冲增强剂,实现对FTA卡保存样本的直接扩增。方法基于常规STR复合扩增试剂盒的扩增体系及引物组,加入增强剂对FTA卡类样本进行直接扩增。结果获得样本STR分型结果清晰、完整、平衡性好,无明显抑制现象存在。结论所研制的FTA卡直扩增强剂能达到FTA卡保存样本的直接扩增检验要求,可应用于法医STR检验。     

AGCU免提取STR荧光检测试剂盒的验证

目的考察AGCU免提取STR荧光检测试剂盒．对保存在滤纸片或FTA卡上血液样本的直接扩增检测情况。方法使用人GCU免提取STR荧光检测试剂盒,对未经提取的滤纸片血液样本、FTA卡血液样本675份进行直接扩增和18个基因座的DNA分型,并对结果的可靠性进行研究。结果18个基因座检测结果与PP16和ID试剂盒分型结果一致,2000年数据库样本成功率92．3％,2001年数据库样本成功率92．6％,2004以后年数据样本及案件样本、亲子鉴定样本成功率在99％以上。结论AGCU试剂盒可以成功地对滤纸片、FTA卡样本的18个STR基因座进行直接扩增检测,检验结果稳定,分型准确。     

DNATyper^(TM) 15试剂盒直接扩增检验纸质样本的研究

目的检验DNATyperTM15直接扩增系统的有效性。方法使用DNATyperTM15直接扩增系统对我国DNA数据库建库4种常见样本类型进行直接扩增检验。结果获得了血滤纸、公安部物证鉴定中心采血卡、博坤采血卡和FTA卡等样本类型的完整DNA分型。结论 DNATyperTM15直接扩增系统能够用于常见纸质样本的检验。     

AmpF(l)STR(R) Identifiler(R) Plus试剂盒快速直接PCR扩增初探

目的 探索可应用于法医实践的快速直接PCR扩增方法,以缩短扩增时间,提高STR分型速率.方法 联合运用AmpF(l)STR(R) Identifiler(R) Plus试剂盒与TaKaRa快速PCR检测试剂构建快速直接PCR体系,以FTA血卡为模板,采用优化后的扩增程序在快速PCR仪上进行扩增,分型结果与常规直接扩增方法相比较.结果 AmpF(l)fSTR(R) Identifiler(R) Plus试剂盒与TaKaRa的快速PCR检测试剂针对血卡的联合扩增,所得STR分型结果与常规方法一致,扩增用时由常规直接扩增所需的175 min缩短为55 min.结论 采用快速直接PCR方法进行扩增,可得到与常规直接扩增一致的DNA分型,扩增时间明显缩短,DNA分型速率大幅提高.     

FTA-DNA直接提取法的研究与应用

目的建立一种简约且易于自动化操作的Whatman FTA卡血样DNA提取方法。方法取直径1．2mm FTA卡血样，分别用FTA-DNA直接提取法及FTA常规提取方法提取DNA，AB-Identifiler^TM试剂盒分别进行10山和25山体系检测比较，并筛选批量grA卡血样DNA自动化提取程序。结果200份grA卡血样分别采用2种方法提取DNA模板，25μl体系PCR-STR检测，分型结果均良好。10μl体系检测，FTA-DNA直接提取法优于FTA常规提取方法，图谱RFU值为1000～2000，采用自动化工作站运行该提取程序较手工操作DNA分型图谱均衡性更佳；采用FTA常规提取方法检测，图谱RFU值100～2000，小片段优先扩增现象明显，且有19％的样本出现丢峰现象，采用自动化工作站运行该程序对其结果改善不明显。经工作站运行FTA-DNA直接提取法自动程序及10山体系检测本2万余份FTA卡采集的血样，均获得16个STR基因座DNA分型结果。结论本文建立的FTA-DNA直接提取法适用于FTA卡血样自动化DNA建库。     

华夏白金系统用于血斑直扩检验效果的评价

目的测试华夏白金直扩系统性能。方法采用华夏白金系统对270份2014年-2015年间采集的滤纸血卡进行10微升体系直扩,采用不同的循环数寻找最佳扩增方案,分析结果。结果该系统用于血卡扩增效果良好,全部样本均获得完整STR基因座分型结果,各基因座等位基因荧光信号扩增均衡,检验成功率达到100%。结论华夏白金系统适合应用于DNA数据库建设工作。     

新鲜血痕样本直接扩增试验条件比较

目的探讨新鲜血痕在不同直接扩增试剂盒的试验条件。方法存放2d内的新鲜血痕FTA卡540份和存放1~3m的陈旧性血痕FTA卡270份,各分别随机均分为3组,每份血痕打3片1.0mm纸片,分别用DNATyperTM15Plus试剂盒、GoldeyeTM20A试剂盒和华夏TM试剂盒在标准条件(说明书条件)、优化条件1(标准条件+1μL DMSO)和优化条件2(标准条件+室温浸泡1h)扩增检验,比较在3种条件下各组STR检验成功率。结果陈旧血痕样本用3种直扩试剂盒,在3种条件下,检验成功率均97.00%,且均高于新鲜血痕。新鲜血痕在标准条件和优化条件1下,成功率为27.22%~31.67%,在优化条件2下,检验成功率相似(97.00%),与标准条件和优化条件1比较,有统计学差异(P0.01)。结论新鲜血痕在加入直接扩增试剂后于室温浸泡1h,可有效提高STR检验成功率。     

荧光STR复合扩增试剂盒的评估过程探索

STR复合扩增检验技术是目前法医DNA检验技术中最重要也是最常用的技术种类之一，随着荧光检测技术和毛细管电泳技术的发展，特别是DNA数据库建设中丰要采用STR复合扩增技术进行基因分型，大大拓展了STR复合扩增检验应用范围。与此同时，STR复合扩增检验试剂成为影响检验质量的重要因素，关系到样本检验分型结果，而分型数据是为法庭提供证据的直接依据，     

基于切口酶的等温全基因组扩增体系的建立与应用

目的 建立依赖切口酶Nt.BstNBI的等温全基因组扩增体系，并对该体系的微量生物物证STR分型效能进行验证。方法 选用切口酶Nt.BstNBI（识别序列为GAGTC）和等温扩增的聚合酶Bst，建立切口酶依赖的扩增体系（NDA）。对DNA样本进行NDA并纯化NDA产物，对NDA前后的样本进行复合扩增和毛细管电泳，检测该方法的有效性、灵敏性。结果 007标准品12个常染色体基因座的扩增效率提高2倍以上，灵敏度约为3 pg/μL;19个Y染色体个基因座的扩增效率提高2倍以上，灵敏度约为6 pg/μL。8个人血样本扩增效率提高2倍以上的常染色体基因座与007标准品一致。结论 本文建立的NDA体系准确性好，能够对包含特定侧翼序列的STR基因座进行有效的线性扩增，对法医微量生物物证的高效扩增检测具有重要意义。     

人体组织在非缓冲福尔马林固定剂中的STR检测时限

目的评估经非缓冲福尔马林固定不同时间后的人体组织STR分型有效性,了解各种人体组织在非缓冲福尔马林固定剂中可获得完全STR分型位点的时限。方法市售40%福尔马林溶液经1∶9稀释后在室温(15～20℃)下固定人体组织,不同时间后取样。以QIAamp DNA法和IQTMDNA System法提取DNA,用quantifiler humanTaqman探针法进行DNA定量,用常规16 STR位点的AmpFSTR identifiler kit和短小片段9 STR位点的AmpFSTR Min-iFiler kit进行PCR扩增,在3100遗传分析仪进行扩增DNA片段长度检测,用GeneMapper ID v3.2对STR位点检出率进行分析。结果福尔马林固定时间、组织类型以及DNA提取方法、PCR的DNA模板终浓度均影响非缓冲福尔马林固定后人体组织STR分型效能。DNA提取用QIAgen法为优,DNA模板终浓度的最佳范围在1～3ng/μL。各类型组织在非缓冲福尔马林固定剂中的降解速率有差异,肺组织的降解速率最慢,肝、肠组织最快。固定时间在4d内的组织可以获得常规STR的完整位点数;固定时间在15d内的组织可以获得miniSTR的完整位点数。结论非缓冲福尔马林固定人体组织时间是影响STR分型的最主要因素,其次组织类型、提取方法、DNA模板浓度及STR基因座的选择也是此类降解样品成功检测的关键因素。     

DNA Typer~(TM)15 plus直扩试剂盒在DNA数据库建设中的应用

目的测试DNA TyperTM15 plus直扩试剂盒的技术性能指标,评价其在DNA数据库建设中的应用价值。方法采用DNA TyperTM15 plus试剂盒,并使用IdentifilerTM和DNA TyperTM15试剂盒进行比较,设定不同体系和引物量、不同退火温度和循环次数以进行方法验证;设定不同模板量标准品、不同比例混合样本,取猪、狗、兔等动物的血液样品,血痕、骨骼、唾液斑等常见检材样本以及不同建库样本,以验证试剂盒灵敏度、特异性、稳定性以及混合样本、常见检材及建库样本的检测能力。结果直扩试剂盒分型结果准确,重复性好,灵敏度可达0.125ng,不同批次间试剂检测结果稳定,对不同检材有很好的适应性。10μL扩增体系时FTA卡和加强型血液采集卡取样直径应为0.5mm,而血滤纸、血液采集卡样本和经典型血液采集卡取样直径应为1.0mm。结论 DNA TyperTM15 plus直扩试剂盒的性能可以满足DNA数据库建设及检案的需要,可在相关实验中选择使用。     

Direct STR amplification from whole blood and blood- or saliva-spotted FTA without DNA purification

The DNA purification step has been thought to be essential for typing of STR DNA. However, this process is time-consuming, and there is a risk of unexpected cross-contamination during purification. We report a new method for direct short tandem repeat (STR) amplification using a newly developed direct PCR buffer, AnyDirect, which can amplify STR loci from whole blood and blood- or saliva-spotted FTA cards without DNA purification. The autosomal and Y chromosomal STR loci were analyzed for whole blood and blood or saliva spots of random individuals, followed by comparison of the results with those of corresponding purified DNA. The results from whole blood and blood spots showed perfect concordance with those from purified DNA without allele or locus drop-out. However, in the case of saliva spots, no amplification or locus drop-out was observed in some of the samples, which offers a topic for further study. Additionally, some commercial hot-start DNA polymerases other than AmpliTaq Gold DNA polymerase were also found to be compatible with this buffer system. Therefore, this direct PCR buffer was demonstrated to be useful for fast forensic DNA analysis or criminal DNA databases for which there is no need to store DNA samples.     

Development of the Investigator STR GO! Kits for the direct amplification of reference samples

STR analysis of forensic reference samples can be performed using a novel direct amplification method. Two assays have been developed for this purpose. One covers the CODIS set of markers and the other covers the ESS including SE33. The method gives balanced DNA profiles with high first pass rates for buccal swabs and blood and buccal cells on FTA paper. The addition of SNP primers compensates for profile imbalances caused by three known binding site mutations.     

微腔型PCR芯片用于法医DNA分析的初步研究

目的为了克服传统PCR热循环仪体积大,运行电压高,耗时长,只能在实验室中应用的缺点,研究了一种微腔型PCR芯片,以期实现现场对STR片段的复合扩增。方法采用在PCR反应缓冲液中加入不同浓度的BSA溶液对芯片进行表面优化处理的方法及不同酶量优化实现对STR片段的有效扩增。结果使用浓度为0．5mg／mL的BSA可得到清晰完整的STR分型结果;加大酶量有益于扩增效率的提高。结论该种微腔型PCR芯片经初步优化后可有效地对STR片段进行复合扩增,经进一步优化可真正实现法医DNA分析的更加微量化和快速化。     

A dedicated automated system for extraction, quantification and STR amplification of forensic evidence samples

Forensic DNA analysis is a multi-step process involving extraction of DNA, quantification of human DNA in the extract, amplification using multiplex STR systems, separation of products, and data analysis. The backlog of forensic casework is increasing worldwide. Automation is one significant way to alleviate the bottleneck of sample processing in forensic labs. The HID EVOlution™ Combination System described here is a robust, reliable sample processing platform, easily adapted to forensic laboratory workflows. Using a variety of forensic sample types including: blood stained FTA paper, cotton fabric and denim, dried blood spiked with known PCR inhibitors, saliva on cotton swabs, and semen stains, we found that yields of human DNA and STR profiles obtained with AmpFlSTR^® Idenitfiler^® kits were complete, highly reproducible, and equivalent to results obtained using the manual PrepFiler™ reagent extraction method. Automated operation was clean, and no cross-contamination was detected between extraction blanks and interspersed high DNA content samples.     

Internal validation of reduced PCR reaction volume of the Qiagen Investigator® Argus X-12 QS Kit from blood samples on FTA cards

The onus of proof in criminal cases is beyond any reasonable doubt, and the issue on the lack of complete internal validation data can be manipulated when it comes to justifying the validity and reliability of the X-chromosomal short tandem repeats analysis for court representation. Therefore, this research evaluated the efficiency of the optimized 60% reduced volumes for polymerase chain reaction (PCR) amplification using the Qiagen Investigator® Argus X-12 QS Kit, as well as the capillary electrophoresis (CE) sample preparation for blood samples on Flinder's Technology Associates (FTA) cards. Good-quality DNA profile (3000–12,000 RFU) from the purified blood sample on FTA card (1.2 mm) were obtained using the optimized PCR (10.0 μL of PCR reaction volume and 21 cycles) and CE (9.0 μL Hi-Di™ Formamide and 0.3 μL DNA Size Standard 550 [BTO] and 27 s injection time) conditions. The analytical and stochastic thresholds were 100 and 200 RFU, respectively. Hence, the internal validation data supported the use of the optimized 60% reduced PCR amplification reaction volume of the Qiagen Investigator® Argus X-12 QS Kit as well as the CE sample preparation for producing reliable DNA profiles that comply with the quality assurance standards for forensic DNA testing laboratories, while optimizing the analytical cost.     

Recovery and STR amplification of DNA from RFLP membranes

Restriction fragment length polymorphism (RFLP) techniques were utilized in the forensic DNA community until the mid 1990s when less labor-intensive polymerase chain reaction short tandem repeat (PCR STR) techniques became available. During the transition from RFLP technology to PCR-based STR platforms, a method for comparing RFLP profiles to STR profiles was not developed. While the preferred approach for applying new technology to old cases would be to analyze the original biological stain, this is not always possible. For unsolved cases that previously underwent RFLP analysis, the only DNA remaining may be restriction cut and bound to nylon membranes. These studies investigate several methods for obtaining STR profiles from membrane bound DNA, including removal of bound DNA with bases, acids, detergents, various chemicals, and conventional cell extraction solutions. Direct multiplex STR amplification of template in the membrane-bound state was also explored. A partial STR profile was obtained from DNA that was recovered from an archived membrane using conventional extraction buffer components, indicating promise for recovering useful STR information from RFLP membranes that have been maintained in long-term frozen storage.     

Isolation of DNA from saliva of betel quid chewers using treated cards

Betel quid (BQ) chewing, a common tradition in tropical areas, often poses a problem during collection and DNA analysis of buccal samples from many indigenous communities for population genetic studies and in forensic analysis of chewed BQ residues. This study evaluated the use of FTA card, a chemically treated filter paper, in collecting buccal samples from long-term BQ users and subsequent PCR-based analysis using nine STR markers. A low overall success rate of amplification was observed in the samples extracted using a standard organic extraction procedure (7%) as compared with those prepared using the FTA card (89%). The presence of inhibitors in liquid DNA samples was verified when control DNA failed to amplify in the presence of an equal volume of liquid BQ samples. The use of the FTA card is more practical during field sampling than handling tubes containing buccal swabs.