Real-time forensic DNA analysis at a crime scene using a portable microchip analyzer

An integrated lab-on-a-chip system has been developed and successfully utilized for real-time forensic short tandem repeat (STR) analysis. The microdevice comprises a 160-nL polymerase chain reaction reactor with an on-chip heater and a temperature sensor for thermal cycling, microvalves for fluidic manipulation, a co-injector for sizing standard injection, and a 7-cm-long separation channel for capillary electrophoretic analysis. A 9-plex autosomal STR typing system consisting of amelogenin and eight combined DNA index system (CODIS) core STR loci has been constructed and optimized for this real-time human identification study. Reproducible STR profiles of control DNA samples are obtained in 2 h and 30 min with ≤0.8 bp allele typing accuracy. The minimal amount of DNA required for a complete DNA profile is 100 copies. To critically evaluate the capabilities of our portable microsystem as well as its compatibility with crime scene investigation processes, real-time STR analyses were carried out at a mock crime scene prepared by the Palm Beach County Sheriff's Office (PBSO). Blood stain sample collection, DNA extraction, and STR analyses on the portable microsystem were conducted in the field, and a successful “mock” CODIS hit was generated on the suspect's sample within 6 h. This demonstration of on-site STR analysis establishes the feasibility of real-time DNA typing to identify the contributor of probative biological evidence at a crime scene and for real-time human identification.     

New resources for the forensic genetics community available on the NIST STRBase website

For more than a decade, the U.S. National Institute of Standards and Technology (NIST) has maintained the short tandem repeat DNA Internet database (STRBase), which is located at http://www.cstl.nist.gov/biotech/strbase/. The purpose of STRBase has been and continues to be an attempt to bring together the abundant literature and information in the forensic genetics field in a cohesive fashion to make current and future work easier. New materials are regularly added to expand the valuable information contained on the STRBase website.     

浙江畲族人群9个STR基因座的遗传多态性

目的调查浙江畲族人群STR基因座的遗传多态性,为群体遗传学和法医学个人识别、亲子鉴定提供基础数据。方法采用AmpFlSTRProfilerPlus试剂盒(ABI公司),ABI310基因自动分析仪对浙江畲族120名无关个体血样的D3S1358、VWA、FGA、D8S1179、D21S11、D18S51、D5S818、D13S317和D7S820等9个STR基因座进行等位基因频率和基因型频率调查。结果获得浙江畲族人群9个STR基因座的基因频率分布资料,所有基因座基因型频率分布均符合Hardy—Weinberg平衡,计算得杂合度(H)0.655～0.960,个人识别率(DP)0.878～0.960,非父排除率(PE)0.363～0.677,多态信息总量(PIC)0.68～0.86。结论该9个STR基因座在浙江畲族人群中呈高度多态性,在法医学及人类遗传学研究中具有重要意义。     

岫岩满族9个STR基因座遗传多态性

目的用复合荧光扩增体系调查辽宁鞍山岫岩满族无关个体D6S1043、D7S3048、D9S925、D11S2368、D14S608、D15S659、D17S1290、D20S470和GATA198B05等9个STR基因座的遗传多态性。方法用本实验室构建的9个常染色体STR基因座荧光复合扩增体系,对辽宁鞍山岫岩满族252个无关个体的DNA进行PCR扩增,3130型基因分析仪电泳检测扩增产物及等位基因分型标准物,GeneMapper誖3.2分析软件中导入本体系Panel和Bin,对电泳结果进行分析,按照重复序列重复次数命名等位基因,使用Power-StatsV12和GENEPOP软件进行统计学分析。结果 9个STR基因座在辽宁鞍山岫岩满族基因型频率分布均符合Hardy-Weinberg平衡(P﹥0.05),多态性信息含量在0.750～0.860之间,杂合度在0.794～0.881之间,个体识别力在0.918～0.968之间,非父排除概率在0.587～0.757之间,累积非父排除率为0.999 96,累积个体识别能力为0.999 999 999 999 1。结论这9个非CODIS系统STR基因座在鞍山岫岩满族群体中等...     

VWA基因座在一个三代家系发生的两次突变

目的探讨短串联重复序列遗传变异的方式。方法用Identifiler^TM试剂盒和DNATyper15^TM试剂盒进行检测,用变性聚丙烯酰胺凝胶电泳法对VWA基因座突变家系中3代父、母、子的DNA样本进行STR基因分型,将需测序的等位基因条带从凝胶上切下,再进行PCR扩增,产物经纯化后进行测序。结果此3代家系中Ⅱ-7、Ⅲ-8发生等位基因变异表现为一个重复单位的增加或减少。其中Ⅱ-7的一条发生突变的等位基因具体来源可知,Ⅲ-8的一条突变等位基因无法确定。结论本文中VWA基因座等位基因突变主要表现为一个重复单位的增加,没有碱基的插入或缺失,突变主要来自父亲,突变等位基因无TCTA（TCTG）3（TCTA）n、TCTA（TCTG）5-6（TCTA）n突变类型,均为TCTA（TCTG）4（TCTA）n型突变。     

A Y‐Chromosomal Haplotype with Two Short Tandem Repeat Mutations*

Abstract:  The male‐specific Y‐chromosomal short tandem repeat (STR) is a useful tool in forensic casework. The Y haplotype comprised of 16 loci, which is amplified simultaneously by AmpFlSTR^® Yfiler^TM PCR kit and provides strong exculpatory evidence in individual identification. We reported a rare Y‐STR profile with a null allele at the DYS448 locus and an off‐ladder allele at the DYS456 locus, when genotyping material from a vaginal swab in an alleged rape case. Sequence analysis revealed that the DYS448 null allele was a true type of null allele because of a total deletion of 11 upstream repeats and 9 bp of the N₄₂ region, and there were numerous primer binding site mutations as well. The amplicon of the DYS456 locus was a small 92‐bp fragment that was off‐ladder, and sequencing analysis showed that there were only 10 repeats (AGAT)₁₀. This Y chromosome haplotype that was comprised of two variations provided helpful evidence for personal identification.     

STR melting curve analysis as a genetic screening tool for crime scene samples

In this proof-of-concept study, high-resolution melt curve (HRMC) analysis was investigated as a postquantification screening tool to discriminate human CSF1PO and THO1 genotypes amplified with mini-STR primers in the presence of SYBR Green or LCGreen Plus dyes. A total of 12 CSF1PO and 11 HUMTHO1 genotypes were analyzed on the LightScanner HR96 and LS-32 systems and were correctly differentiated based upon their respective melt profiles. Short STR amplicon melt curves were affected by repeat number, and single-source and mixed DNA samples were additionally differentiated by the formation of heteroduplexes. Melting curves were shown to be unique and reproducible from DNA quantities ranging from 20 to 0.4 ng and distinguished identical from nonidentical genotypes from DNA derived from different biological fluids and compromised samples. Thus, a method is described which can assess both the quantity and the possible probative value of samples without full genotyping.     

中国汉族人群17个Y-STR基因座突变情况分析

目的 调查分析17个Y-STR基因座等位基因突变的情况.方法 收集中国汉族人群867对父子共1 649份男性血样本.采用YfilerTM复合扩增试剂盒进行17个Y-STR基因座分型,共检测出14 739次等位基因传递,统计各基因座发生等位基因突变的频率.结果 在17个基因座中发现涉及13个基因座共41次突变,其中一步突变40次(97.6％),两步突变1次(2.4％);突变共涉及40对父子,其中39对仅1个基因座发生突变(97.5％),1对同时有2个基因座发生突变(2.5％);平均突变率为2.8×10-3(95％CI 2.0～3.8×10-3).等位基因突变时获得重复单位数19次,丢失重复单位数22次,两者比例接近.结论 中国汉族人群Y-STR基因座突变可涉及多数基因座,突变率在2.8×10-3左右,在数据库的建立与应用中应重视,注意采用相关方法进行甄别.     

河南汉族群体6个STR基因座遗传多态性研究

目的　通过研究 6个STR基因座FGA ,TPOX ,D3S135 8,vWA ,D8S1179,D2 1S11的遗传多态性 ,了解它们在河南汉族人群中的多态分布 ,与其他群体进行比较 ,得出遗传距离 ,并了解它在法医学中的应用价值。　方法　采用多聚酶链式反应扩增这 6个基因座 ,采用非变性聚丙烯酰氨凝胶电泳银染显色分析。　结果　得出这 6个基因座在河南汉族人群中的基因频率 ,并计算得出杂合度、个体识别率、非父排除率 ,与其他群体比较得出进化距离。　结论　这 6个基因座有较高的杂合度 ,并且具有相对遗传稳定性 ,在人群中的分布符合Hardy -Weinberge平衡 ,有较高的法医学价值 ,可以应用于个体识别和亲权鉴定。     

STR位点D19S253和D8S1179的法医学意义及应用研究

为评估STR位点D19S253和D8S1179的法医学应用价值，应用PCR和PAG垂直电泳技术对两位点的种属特异性，检测灵敏度，以及同一个体不同组织分型的同一性及不同基质和不同保存时间的斑痕分型等与法医应用有关的问题进行了研究，D19S253和D8S1179位点的检测灵敏度分别为0．25ng及0．5ng，同时两位点具有较高的种属特异性，同一性及较好重复性，且能够复合扩增，表明D19S253和D8S1179是法医学检案中较实用的两个STR标记。