法医DNA分型的可重复性

为了了解国内法医DNA分型的可靠性，选择酪氨酸羟化酶基因第1内含子什＂mantyrosinehydroxylasegene,intron1）的短串联重复序列（STR）TH01基因座为遗传标记，在国内5个法医实验室进行了DNA分型的可重复性研究，报道如下。材料与方法一、样本制备和分送国内5个法医实验室参加本次研究工作，由华西医科大学法医学系作为协调单位，负责制备与分送盲测样本。每个法医实验室4份样本，2份为纯化DNA，2份为血痕。血液样品采自成都地区无血缘关系汉族个体，常规方法提取DNA；血痕样本由另外两名个体新鲜血液0．5ml滴于滤纸上制成，室温晾干…     

荧光原位杂交技术在法庭科学DNA检验中的应用

目的运用荧光原位杂交技术结合激光显微切割技术,分离法医物证男女混合样本中的男性细胞和女性细胞,并进行DNA分型。方法通过双色荧光原位杂交,Y染色体标记上绿色信号,X染色体标记上红色信号,在荧光显微镜下识别男性细胞和女性细胞,并通过激光显微切割技术分别获得男性细胞和女性细胞进行DNA分型。结果运用荧光原位杂交技术,能够分别标记法医物证男女混合样本中的男性细胞和女性细胞,并通过激光显微切割技术获得各自的DNA分型。结论荧光原位杂交技术结合激光显微切割技术,可应用于法医物证男女混合样本的检验,提高个体识别能力。     

法庭科学DNA实验室规范化建设的初体验

近几年来,法庭科学DNA分析技术及其数据库建设在国内发展迅速,各类刑事案件的侦破及法庭举证中该技术的应用日趋广泛。各地法医DNA实验室检验量持续增加,专业技术人员长期超负荷工作,鉴定质量难以保障,已成为普遍面临的问题。因此,尽快开展法庭科学DNA实验室的规范化建设显得尤为重要。现将本实验室开展规范化建设情况及工作中的体会介绍如下,供同行交流、参考。1天津市法医DNA实验室规范化建设情况本实验室自1990年组建以来,历经RFLP、VN-TR、STR等法医DNA分析技术各个发展时期的磨砺,逐步走上了标准化、规范化的发展轨道。针对…     

澳大利亚联邦警察局法医DNA实验室管理与质量控制简介

在国家留学基金委资助下，笔者于2011年作为国家公派访问学者赴澳大利亚联邦警察局（Austral—ianFederalPolice，简称AFP）法医及数据中心（Fo—rensicandDataCentre）交流学习。本文重点介绍最新的澳大利亚联邦警察局法医DNA实验室管理的基本情况及其目前质量控制（QualityControl，简称QC）的主要措施，结合我国的实际国情及法医DNA实验室管理及发展现状，探讨我国可以借鉴的法医DNA实验室管理制度、运行机制、质量管理等方面先进经验，供同行们借鉴和参考。     

一核酸清洁剂在法医DNA实验室防污染上的应用

法医DNA实验室污染是导致鉴定结论错误的重要因素,DNA实验室应加强实验室管理,重点防范实验室的DNA污染,并解决污染问题。一核酸清洁剂由A、B两种组分构成,两种组分配合使用能破坏DNA结构,防止DNA在PCR中的复制。该核酸清洁剂能有效防范DNA实验室的污染,并解决实验室的污染问题,能很好的应用于法医DNA实验室质量监控管理。本文通过实验对比分析,阐明了该核酸清洁剂的作用效果。     

动物DNA分析技术及其法医学应用

动物DNA分析是法医非人源DNA分析的重要内容,对提供侦查线索和审判依据具有特殊的法医学价值.法医动物DNA分析主要涉及家养动物和野生动物两大类别.本文以动物DNA分析在法庭科学中的应用为切入点,综述了动物个体识别、亲缘鉴定、物种鉴定等,动物DNA分析中的遗传标记、检测技术等,并提出法医动物DNA分析存在的问题以及未来...     

限制性组合分析法推定男女混合斑中个体分型初探

混合斑是指包含两私或两名以上个体的混合生物检材，红多数情况下，此类检材的DNA分型往往表现为两人或多人的混合分型，使结果分析较为复杂[1]．本义尝试采川2005年国际法医遗传学会（ISFG）推荐的关于混合斑结果分析中的计算方法对混合斑案件中单一个体DNA分型结果进行分析。     

基于下一代测序的全解析度STR分型研究进展与展望

下一代测序技术具有高通量、高速度、集成化、低成本等显著优势,近年来已在科研和临床诊断领域得到广泛应用,在法医遗传学领域亦具有重要应用前景。当前主流的STR分型方法仅关注序列的长度多态性,然而由于核心重复结构存在差异或扩增区段内存在SNP,序列长度相等的等位基因可能是具有遗传稳定性的完全不同的等位基因,此类STR序列多态性是个体识别或亲缘关系分析的宝贵资源。基于下一代测序的STR分型在现有数据输出方式基础上,允许进一步关注STR的序列多态性,对STR基因座进行全解析度分型,显著提升STR基因座的个体识别能力。本文以法医STR遗传标记和下一代测序技术为关注焦点,系统综述基于下一代测序的全解析度STR分型领域国际最新研究进展,深入探讨该技术在法医DNA实验室的实际应用潜力和可能面临的挑战,希冀对相关研究和实践提供参考。     

STR复合扩增及荧光检测技术在个体识别中的应用

目的 :使用 310型遗传分析仪对D3S1358等 10个位点进行基因型检测并应用于法医物证学个体识别案件。方法 :用PCR复合扩增结合四色荧光检测技术对样本DNA进行基因分型。结果 :常见物证检材可成功地得到检验。结论 :这些位点适用于法医物证学个体识别。     

二代测序技术在法医遗传学中的应用研究进展(2011～2016)

对生物检材进行DNA分型是解决法医遗传学实践中个体识别和亲权鉴定问题的重要步骤,法医学实践中复杂生物检材和复杂亲缘关系鉴定等一直是现有的检测分析技术的难点和挑战。随着DNA技术的发展,新的检测分析技术不断引入到法医遗传学领域,以期提高检测效能。二代测序技术具有测序通量高、成本低等特点,能够获得样本DNA详细序列和相对含量等信息,有助于生物检材的检测和案件的分析。二代测序技术在法医遗传学领域的应用受到广泛关注,相关的应用研究逐渐增多。本文就目前法医遗传学领域借助二代测序技术对遗传标记分析的研究进展进行总结,希望能为相关研究和应用提供参考。     

Isolation of deoxyribonucleic acid (DNA) from saliva and forensic science samples containing saliva.

Saliva and saliva-stained materials were examined as potential sources of deoxyribonucleic acid (DNA) for DNA analysis and identity testing. In this paper, the authors demonstrate that DNA was isolated and DNA banding patterns suitable for DNA typing were obtained from fresh saliva and various saliva-stained materials, such as envelopes, buccal swabs, gags, and cigarettes. Furthermore, DNA and DNA banding patterns were obtained from actual forensic evidentiary samples containing mixed saliva/semen stains. The DNA banding patterns obtained from saliva or saliva-stained material were indistinguishable from the patterns obtained from blood or hair from the same individual. Intact DNA was readily isolated and DNA banding patterns were obtained from saliva stored at -20 degrees C and dried saliva stains stored under varying conditions. We conclude that saliva and saliva-stained material can be good sources of DNA for analysis and for DNA typing in certain forensic settings.     

Chelex法和两种磁珠法提取接触DNA效果的比较

目的比较Chelex法、DNA IQ磁珠法、EQ国产磁珠法对接触DNA的提取效果。方法将稀释为10ng、100ng的标准品DNA,分别采用Chelex法、DNA IQ磁珠法、EQ国产磁珠法处理;对30例烟蒂和30例牙刷分别采用Chelex法、DNA IQ磁珠法和EQ国产磁珠法提取DNA,然后进行PCR定量和STR检测。结果Chelex法对DNA的提取无损失,DNA IQ磁珠法、EQ国产磁珠法对DNA的提取均有不同程度的损失;烟蒂、牙刷等检材采用Chelex法提取的接触DNA量和IPC CT值显著高于IQ磁珠法、EQ国产磁珠法,但STR检验成功率却低于IQ磁珠法、EQ国产磁珠法。2种磁珠法提取的DNA量、IPC CT值和STR检验成功率无显著性差异。结论污染轻、杂质少的接触DNA检材,用Chelex法提取最为方便快捷;IQ磁珠法、EQ国产磁珠法更适合污染接触DNA检材的提取及自动化操作。     

Forensic human identification: Investigation into tooth morphotype and DNA extraction methods from teeth

When a body is decomposed, hard tissues such as teeth may provide the only DNA source for human identification. There is currently no consensus as to the best DNA extraction method, and there is a lack of empirical data regarding tooth morphotype and condition that may impact DNA recovery. Therefore, this study sought to investigate which variables significantly improved DNA concentration, integrity and profiling success. A total of 52 human teeth were assessed, representing all tooth morphotypes from three deceased individuals. DNA was extracted using both the QIAamp® DNA Investigator Kit and the phenol-chloroform method. DNA concentration and degradation index were assessed using real time PCR, prior to conventional DNA profiling. Contrary to international guidelines promoting the use of molars, DNA profiling from molars was the least successful, with premolars, followed by canines, performing the best. The presence of fillings reduced the DNA quantity and quality obtained and may explain the poor performance of molars. DNA from the maxillae were significantly less degraded when the QIAamp® was used, although this did not influence DNA profiling success. A significant increase in DNA concentration, integrity and profiling success was observed in diseased teeth (periodontitis) compared to those without disease. This may be due to increased white blood cell presence at the site. There was no significant difference in DNA profiling success between the two DNA extraction methods. However, different teeth yielded failed DNA profiles for each extraction method, suggesting that repeated attempts, using alternative DNA extraction methods, is recommended. The recovery of additional DNA profiling information from degraded samples may help to ultimately reduce the burden of unidentified human remains.     

4种固相颗粒吸附法提取滤纸血痕DNA效果的比较

目的探讨4种固相颗粒吸附法提取滤纸血痕样本DNA的效果。方法含有1μL静脉血的滤纸血痕180份,分为4组,每组45份。分别采用4种固相颗粒吸附法(DNAIQ~(TM)系统、D盾超敏DNA提取试剂盒、超高效硅珠纯化DNA提取试剂盒和常规的硅珠法)对上述样本进行DNA提取,对比各组DNA溶液的浓度及STR分型检验结果。结果 D盾超敏DNA提取试剂盒[(3.764±1.790)μg/mL]、超高效硅珠纯化DNA提取试剂盒(3.634±1.112)及常规硅珠法(3.350±1.250)提取到DNA溶液的浓度无统计学差异(P0.05),但均高于DNA IQ~(TM)系统(1.864±1.207)(P0.001);D盾超敏DNA提取试剂盒、超高效硅珠纯化DNA提取试剂盒及常规硅珠法样本图谱峰高大于DNA IQ~(TM)系统(P0.001),超高效硅珠纯化DNA提取试剂盒和常规硅珠法样本图谱峰高大于D盾超敏DNA提取试剂盒(P0.01)。结论 D盾超敏DNA提取试剂盒、超高效硅珠纯化DNA提取试剂盒及常规硅珠法对于滤纸血痕的DNA提取效率高于DNA IQ~(TM)系统;超高效硅珠纯化DNA提取试剂盒和常规硅珠提取到的DNA溶液可能具有更高的质量。     

Quantification of forensic DNA from various regions of human teeth

When the use of traditional forensic identification methods such as fingerprints or dental radiographs is difficult or impossible, identification by DNA analysis has proven valuable. In situations such as explosions or airplane crashes, identification is even more difficult because human remains are often fragmented and may be commingled. Teeth are a useful source of DNA and can often survive extreme environmental conditions. However, teeth may be fragmented into several identifiable regions. Therefore it is important to determine if DNA is present in forensically significant yields in all regions of the tooth. The main objectives of this study were to determine which region(s) of the tooth contains quantifiable DNA, if all regions contain similar yields of DNA and whether there is enough DNA in all regions to justify DNA extraction from a found tooth fragment. Results demonstrate that there is sufficient quantity of DNA in the crown body, root body, and root tip to support DNA extraction. Additionally, the root body is the region with the highest yield of DNA. This information will aid forensic DNA analysts in producing a useful DNA profile in a timely and cost-effective manner.     

Comparison of five DNA quantification methods

Six commercial preparations of human genomic DNA were quantified using five quantification methods: UV spectrometry, SYBR-Green dye staining, slot blot hybridization with the probe D17Z1, Quantifiler™ Human DNA Quantification kit and RB1 rt-PCR. All methods measured higher DNA concentrations than expected based on the information by the manufacturers. UV spectrometry, SYBR-Green dye staining, slot blot and RB1 rt-PCR gave 39, 27, 11 and 12%, respectively, higher concentrations than expected based on the manufacturers’ information. The DNA preparations were quantified using the Quantifiler™ Human DNA Quantification kit in two experiments. The measured DNA concentrations with Quantifiler were 125 and 160% higher than expected based on the manufacturers’ information. When the Quantifiler™ human DNA standard (Raji cell line) was replaced by the commercial human DNA preparation G147A (Promega) to generate the DNA standard curve in the Quantifiler™ Human DNA Quantification kit, the DNA quantification results of the human DNA preparations were 31% higher than expected based on the manufacturers’ information. The results indicate a calibration problem with the Quantifiler™ human DNA standard for its use with the Quantifiler™ Human DNA Quantification kit. The possible reasons for the problem are discussed and a solution is suggested. The results emphasise the need for standard reference DNA material and standard methods for DNA quantification.     

An innovative transfer DNA experimental design and qPCR assay: Protocol and pilot study

Forensic “touch” DNA samples are low-quantity samples that are recovered from surfaces that have been touched by single or multiple individuals. These samples can include DNA from primary contributors who directly touched the surface, as well as secondary contributors whose DNA was transferred to the surface through an intermediary. It is difficult to determine the type of transfer, or how often and under what conditions DNA transfer occurs. In this paper, we present an innovative protocol that combines (1) a paired male and female transfer DNA experimental design in which the presence of male DNA indicates secondary transfer and (2) a cost-effective quantitative PCR (qPCR) assay of a sex-specific region in the Amelogenin gene to detect male and female DNA. We evaluate the ability of the Amelogenin qPCR assay to detect low concentrations of male and female DNA in mixed samples. We also test experimental DNA samples using our transfer DNA protocol to differentiate primary and secondary DNA transfer. Male DNA was detected in the majority of known mixed samples, even in samples with 4× more female DNA—this result demonstrates the ability to detect low concentrations of male DNA and the presence of secondary transfer DNA in our experimental design. Primary DNA transfer was detected in 100% of our experimental trials and secondary DNA transfer was detected in 37.5% of trials. Our innovative protocol mimics realistic case scenarios to establish rates of primary and secondary DNA transfer in an inexpensive and simplified manner.     

Recovery of DNA for forensic analysis from lip cosmetics.

To obtain a reference DNA profile from a missing person, we analyzed a variety of personal effects, including two lip cosmetics, both of which gave full DNA profiles. Further investigations were undertaken to explore this previously unreported source of DNA. We have tested a range of brands and types of lip cosmetics. Our studies have revealed that lip cosmetics are an excellent source of DNA, with almost 80% of samples giving a result. However, artifacts are frequently observed in the DNA profiles when Chelex is used for the DNA extraction and additional DNA purification procedures are required to ensure that an accurate DNA profile is obtained.     

The value of DNA material recovered from crime scenes

Abstract:  DNA material is now collected routinely from crime scenes for a wide range of offenses and its timely processing is acknowledged as a key element to its success in solving crime. An analysis of the processing of approximately 1500 samples of DNA material recovered from the property crime offenses of residential burglary, commercial burglary, and theft of motor vehicle in Northamptonshire, U.K. during 2006 identified saliva and cigarette ends as the main sources of DNA recovered (approximately 63% of samples) with blood, cellular DNA, and chewing gum accounting for the remainder. The conversion of these DNA samples into DNA profiles and then into matches with offender profiles held on the U.K. National DNA database is considered in terms of the ease with which Crime Scene Examiners can recover DNA rich samples of different sources, the location of the DNA at the crime scene, and its mobility. A logistical regression of the DNA material recovered has revealed a number of predictors, other than timeliness, that greatly influence its conversion into a DNA profile. The most significant predictor was found to be Crime Scene Examiner accreditation with offense type and DNA sample condition also being relevant. A similar logistical regression of DNA samples profiled that produced a match with an offender on the U.K. National DNA database showed no significance with any of the predictors considered.     

利用AutoMate Express~(TM)自动化法医DNA提取系统提取骨骼及牙齿DNA

目的探讨建立骨骼及牙齿DNA自动化提取的新方法。方法将33份骨骼及15份牙齿样本分别用冷冻研磨和手工处理两种方法研磨成粉,采用AutoMate ExpressTM自动化法医DNA提取系统提取DNA并定量。结果 AutoMate ExpressTM自动化法医DNA提取系统能够在3h左右完成骨骼、牙齿DNA的提取,两种方法处理的骨骼样本所得DNA质量浓度差异无统计学意义。冷冻研磨处理的骨骼和牙齿样本均获得了较好的STR分型结果,且牙齿样本所得DNA质量浓度高于手工提取所得。结论应用AutoMate ExpressTM自动化法医DNA提取系统是自动化提取骨骼、牙齿DNA的一种新方法,可应用于法医实际案件检验。