DNA分析技术在法科学中的应用及展望

本综述对DNA指纹、PCR -VNTR、PCR -STR、PCR -mtDNA测序等技术的发展 ,以及其在法科学中的应用领域和发展前景作了系统的阐述。认为由于DNA分析技术所具有的特点 ,使之已成为现今法科学生物检材检验的主要手段之一。阐述了现阶段DNA分析技术已向标准化、自动化和高鉴别机率方向发展 ,以及建立DNA罪犯数据库的必要性和应用价值     

中国法庭科学DNA数据库

本文综述了中国法庭科学DNA数据库的建立和发展过程、DNA数据库结构、内容、特点、作用以及存在的问题、发展方向、展望,目的是为如何进一步建设好具有中国特色的DNA数据库提供借鉴。     

The use of wildcards in forensic DNA database searches

Forensic genetic databases contain millions of DNA profiles worldwide. An allelic drop-out at a heterozygous locus (two different alleles) erroneously results in an observed homozygous profile. To guard against this, wildcards are induced for homozygous profiles. The wildcard represents any allele including the observed allele.In this paper, theoretical expressions for the number of matching loci are derived, results shown from a Danish dataset with more than 50,000 DNA profiles and simulations used to link homozygosity with the drop-out probability, which best mimics wildcard matching.     

The impact of human-technology cooperation and distributed cognition in forensic science: biasing effects of AFIS contextual information on human experts

Experts play a critical role in forensic decision making, even when cognition is offloaded and distributed between human and machine. In this paper, we investigated the impact of using Automated Fingerprint Identification Systems (AFIS) on human decision makers. We provided 3680 AFIS lists (a total of 55,200 comparisons) to 23 latent fingerprint examiners as part of their normal casework. We manipulated the position of the matching print in the AFIS list. The data showed that latent fingerprint examiners were affected by the position of the matching print in terms of false exclusions and false inconclusives. Furthermore, the data showed that false identification errors were more likely at the top of the list and that such errors occurred even when the correct match was present further down the list. These effects need to be studied and considered carefully, so as to optimize human decision making when using technologies such as AFIS.     

A standard procedure for accommodating forensic anthropological and genetic analysis of decomposing human remains from tropical climates

At the Medical Legal Center in Ribeirão Preto, Brazil (CEMEL/FMRP-USP), unidentified decomposing bodies routinely undergo soft tissue removal (by immersion in water at 80–90 °C for 24 h) prior to an anthropological analysis intended to yield a biological profile of age, sex, ancestry, height, pathology and so on. In the event that this analysis is unsuccessful, samples may be submitted for DNA profiling. The tropical climate and the defleshing process may confound preservation, recovery and analysis of DNA, however. In order to establish an optimal standardized protocol for identification of decomposing human remains from a tropical climatic region, the outcome of anthropological and genetic analyses was compared, along with the utility of bone (mainly femur and sternum) and teeth (mainly molar) specimens for DNA analysis. In a sample (n = 39) of partially skeletonized remains, anthropological analysis was sufficient for identification in eight cases. In further six cases, DNA profiling was successfully attempted. As a consequence of our study, we recommend collection of 1–2 well preserved teeth prior to defleshing and anthropological analysis in these circumstances.     

Quadruplex real-time PCR for forensic DNA quantitation

Forensic DNA quantitation is an important initial step preceding PCR amplification of the STR loci even though information concerning the quality of the DNA is not revealed. A quadruplex real-time PCR (qPCR) assay was developed to quantify four DNA targets: (1) the human RB1 gene in nuclear DNA, (2) the DAZ gene present on the human Y chromosome, (3) the ATPase8 gene present in human mitochondrial DNA and (4) an artificial internal positive control to reveal possible PCR inhibition. Primers labeled with four different fluorophores are used together with a single quencher using the antiprimer quenching-based qPCR method in one reaction, in which the resultant amplicons are less than 127 bp in size. Sensitivity was shown to be less than ten copies for all four targets in the absence of amplification inhibition. The amplification remained sensitive in the presence of an excess of non-human DNA.     

A fast analysis system for forensic DNA reference samples

On January 1st, 2006, the Swedish legislation on obtaining DNA reference samples from suspects and the recording of DNA profiles in databases was changed. As a result the number of samples analysed at the Swedish National Laboratory of Forensic Science (SKL) increased from about 4500 in 2005 to more than 25,000 in 2006. To meet this challenge, SKL launched a new analysis system to create an unbroken chain, from sampling to incorporation of a profile in the national DNA database and subsequent automatic generation of digitally signed hit reports. The system integrates logistics, digital data transfer, new functions in LIMS (ForumDNA Version 4, Ida Infront AB) and laboratory automation. Buccal swab samples are secured on a FTA^® card attached to an identity form, which is barcoded with a unique sample ID. After sampling, the police officer sends a digital request to SKL. The sample is automatically registered in LIMS and processed on delivery. The resulting DNA profiles are automatically classified according to quality using a custom-made expert system. Building the evaluation around mathematical rules makes it reproducible, standardised and minimises manual work and clerk errors. All samples are run in duplicate and the two profiles are compared within LIMS before incorporation in the database. In the first year of operation, the median time for completion of an analysis was 3 days, measured from delivery of the sample to incorporation of the profile in the national DNA database. In spite of the dramatic increase in the number of reference samples there was no backlog.     

Application of BioRobot M48 to forensic DNA extraction

The development of a nucleic acid extraction method based on magnetic separation has opened up possibilities forl automation of DNA extraction. The BioRobot M48 is one of robotic stations applicable to automated DNA extraction in forensics. However, each new method should be thoroughly validated before application to routine casework. Our aim was to compare the effectiveness of the currently utilized organic/Microcon 100 based extraction procedure and magnetic extraction with BioRobot M48. The DNA concentration of DNA extracts obtained from different kinds of typical forensic material was evaluated followed by amplification with the SGM Plus or Identifiler kit and capillary electrophoresis using ABI 3100 Avant. We can conclude that BioRobot M48 is a very effective instrument for DNA extraction from most specimens and can be successfully applied in forensic laboratories.     

Visual attention and expertise for forensic signature analysis

Eye tracking was used to measure visual attention of nine forensic document examiners (FDEs) and 12 control subjects on a blind signature comparison trial. Subjects evaluated 32 questioned signatures (16 genuine, eight disguised, and eight forged) which were compared, on screen, with four known signatures of the specimen provider while their eye movements, response times, and opinions were recorded. FDEs' opinions were significantly more accurate than controls, providing further evidence of FDE expertise. Both control and FDE subjects looked at signature features in a very similar way and the difference in the accuracy of their opinions can be accounted for by different cognitive processing of the visual information that they extract from the images. In a separate experiment the FDEs re-examined a reordered set of the same 32 questioned signatures. In this phase each signature was presented for only 100 msec to test if eye movements are relevant in forming opinions; performance significantly dropped, but not to chance levels indicating that the examination process comprises a combination of both global and local feature extraction strategies.     

Trends in forensic DNA database:transnational exchange of DNA data

The transnational exchange of forensic DNA data has become a modern trend in fighting cross-border crime,terrorism and illegal immigration.Forensic DNA data all...     

Use of subpopulation data in Australian forensic DNA casework

DNA profiling evidence presented in court should be accompanied by a reliable estimate of its evidential weight. In calculating such statistics, allele frequencies from commonly employed autosomal microsatellite loci are required. These allele frequencies should be collected at a level that appropriately represents the genetic diversity that exists in the population. Typically this occurs at broadly defined bio-geographic categories, such as Caucasian or Asian. Datasets are commonly administered at the jurisdictional level. This paper focuses on Australian jurisdictions and assesses whether this current practice is appropriate for Aboriginal Australian and Caucasian populations alike. In keeping with other studies we observe negligible differences between Caucasian populations within Australia when segregated geographically. However segregation of Aboriginal Australian population data along contemporary State and Territory lines appears to mask the diversity that exists within this subpopulation. For this reason datasets collated along more traditional lines may be more appropriate, particularly to distinguish the most genetically differentiated populations residing in the north of the continent.     

人线粒体DNA序列分析在法医学中的应用研究及其进展

综述人线粒体DNA(m tDNA)序列分析在法医学种属鉴别、个体识别,以及个体年龄推断中的应用研究及其进展,展望对m tDNA异质性的研究及建立人m tDNA数据库,并具有重要的法医学实践意义。     

中国法医学会物证专业委员会法医DNA分析的若干建议

中国法医学会法医物证学专业委员会与国际法医遗传学会中文专委会于2006年10月在成都召开学术会议。我们的讨论强调有必要将国际法医遗传学会的信息及时传递到中国。因此,按照国际法医遗传学会的指南,我们推荐混合斑分析,法医DNA数据库及新遗传标记选择标准供同行参考。     

人类线粒体DNA异质性研究进展及在法医学中的应用

线粒体DNA(mtDNA)异质性的存在使其在法医学应用变得复杂。本文对mtDNA异质性形成的可能原因、异质性的分布和遗传特点、异质性的筛查和定量方法、异质性对法医学的影响以及异质性的研究和展望等方面进行综述,探讨异质性在法医学上的应用价值。     

Validation studies of rapid stain identification-blood (RSID-blood) kit in forensic caseworks

When bloodstains are detected at crime scene using presumptive tests (e.g. luminol, phenolphthalein, leuchomalachite green), it is important to establish the real human nature of each stain. This is possible using confirmatory tests. One of these is rapid stain identification-blood (RISD-blood) a lateral flow immuno-chromatographic strip test format which allows the identification of human blood by detection of glycophorin A, a red blood cell membrane antigen, using two anti-human glycophorin A (GPA) monoclonal antibodies.The aim of this study is to assess the sensitivity of RSID-blood test in old, degraded bloodstains and in some bloodstains previously treated with BlueStar Forensic, a presumptive test which is often used in crime scene investigations to detect latent bloodstains. The genetic analysis of all bloodstains of confirmed human nature was subsequently performed using the AmpF1STR Identifiler PCR Amplification Kit (Applied Biosystems), to validate the possibility of obtain a consistent and reliable DNA typing results.     

中国蒙古族群体mtDNA测序的聚类分析及其法医学意义

目的建立一种既节省模板、又能延长测序长度的m tDNA单倍型(群)分析方法,构建中国蒙古族mtDNA单倍型类型关系树。方法用复合扩增、巢式PCR对201名中国蒙古族m tDNA样本进行D-环区、3010~3460、4640~5204、10171~10659和14478~15204编码区域的测序分析,部份样品进行L3953/H4508等区域的测序;根据其多态界定各样本单倍型并进行聚类分析。结果L15996/H107等巢式PCR扩增产物经测序检验结果互不干扰,其分型以A等东亚人群常见的单倍型(群)为主,包括部份HV、K、J、I和U等欧洲人群优势单倍型(群),23个单倍群和共53个单倍型全部归为欧亚人群特有的M和N两大类单倍类群并呈巢式聚类。结论本研究选取的测序区域适用于构建我国各民群的m tDNA单倍型(群);复合扩增、巢式PCR法既节省模板DNA,又延长测序的长度,适用于法医学、考古学研究中的微量样本的检测。     

Y- STRs and forensic parameters in African populations

Short Tandem Repeat polymorphisms have been widely studied in the world, since specific databases are required to produce correct estimates of forensic statistical parameters. In this regard, Y-chromosome STRs have been studied mainly in Europe but are relatively scarce for sub-Saharan populations, despite these populations are represented in most of the Western countries. The aim of this work is to detect groups of populations with the lowest genetic variability within the African context. This allows to establish the relative homogeneity of Y-STRs databases for forensic casework and eventually to provide a wider insight into the African genetic history.     

The efficiency of Y-chromosome markers in forensic trace analysis and their inclusion in the Austrian National DNA Database

Y-STR markers are a valuable tool in the analysis of biological traces in which a mixture of male and female trace material is to be expected. It is possible to generate a Y-chromosome DNA profile, even if all the prior sperm tests are negative and no sign of any male component is found in amelogenin. In 38 of a total of 239 sexual offences a perpetrator trace was identified solely using Y-STR analysis. Based on these findings, the Austrian National DNA Database was expanded to include Y-STRs in 2012 with the primary objective to identify serial sexual offences.