10个STR基因座荧光复合扩增体系的研制

目的建立10个STR基因座荧光标记复合扩增体系,并评价其法医学应用价值。方法在北京、山西、广东汉族,辽宁满族、西藏藏族群体中调查STR基因座遗传多态性,筛选出9个具有高度多态性和法医应用价值的STR基因座及性别基因座。构建四色荧光素标记复合扩增体系,制备等位基因分型标准物,编制分析软件,并对体系的种属特异性、灵敏度、稳定性、混合样本等检测能力进行考察。结果建立的复合扩增体系遗传稳定好,累积非父排除率可达0.999 96,累积个体识别率可达0.999 999 999 999 3;与CODIS系统均不存在连锁遗传;各基因座间布局合理、无杂峰、扩增结果清晰易辨,并可实现检测分析自动化。体系种属特异性较好,灵敏度为0.1ng,稳定性好,混合样本检出范围在2∶8～8∶2之间。实际案例检材检测结果好。结论本文建立的复合扩增体系在法医学实践中有较好的应用价值。     

RNA/DNA co-analysis from blood stains—Results of a second collaborative EDNAP exercise

A second collaborative exercise on RNA/DNA co-analysis for body fluid identification and STR profiling was organized by the European DNA Profiling Group (EDNAP). Six human blood stains, two blood dilution series (5-0.001 μl blood) and, optionally, bona fide or mock casework samples of human or non-human origin were analyzed by the participating laboratories using a RNA/DNA co-extraction or solely RNA extraction method. Two novel mRNA multiplexes were used for the identification of blood: a highly sensitive duplex (HBA, HBB) and a moderately sensitive pentaplex (ALAS2, CD3G, ANK1, SPTB and PBGD). The laboratories used different chemistries and instrumentation. All of the 18 participating laboratories were able to successfully isolate and detect mRNA in dried blood stains. Thirteen laboratories simultaneously extracted RNA and DNA from individual stains and were able to utilize mRNA profiling to confirm the presence of blood and to obtain autosomal STR profiles from the blood stain donors. The positive identification of blood and good quality DNA profiles were also obtained from old and compromised casework samples. The method proved to be reproducible and sensitive using different analysis strategies. The results of this collaborative exercise involving a RNA/DNA co-extraction strategy support the potential use of an mRNA based system for the identification of blood in forensic casework that is compatible with current DNA analysis methodology.     

Assessing a novel room temperature DNA storage medium for forensic biological samples

The ability to properly collect, analyze and preserve biological stains is important to preserving the integrity of forensic evidence. Stabilization of intact biological evidence in cells and the DNA extracts from them is particularly important since testing is generally not performed immediately following collection. Furthermore, retesting of stored DNA samples may be needed in casework for replicate testing, confirmation of results, and to accommodate future testing with new technologies.A novel room temperature DNA storage medium, SampleMatrix™ (SM; Biomatrica, Inc., San Diego, CA), was evaluated for stabilizing and protecting samples. Human genomic DNA samples at varying amounts (0.0625-200 ng) were stored dry in SM for 1 day to 1 year under varying conditions that included a typical ambient laboratory environment and also through successive freeze-thaw cycles (3 cycles). In addition, spiking of 1-4× SM into samples prior to analysis was performed to determine any inhibitory effects of SM. Quantification of recovered DNA following storage was determined by quantitative PCR or by agarose gel electrophoresis, and evaluation of quantitative peak height results from multiplex short tandem repeat (STR) analyses were performed to assess the efficacy of SM for preserving DNA.Results indicate no substantial differences between the quality of samples stored frozen in liquid and those samples maintained dry at ambient temperatures protected in SM. For long-term storage and the storage of low concentration samples, SM provided a significant advantage over freezer storage through higher DNA recovery. No detectable inhibition of amplification was observed at the recommended SM concentration and complete profiles were obtained from genomic DNA samples even in the presence of higher than recommended concentrations of the SM storage medium. The ability to stabilize and protect DNA from degradation at ambient temperatures for extended time periods could have tremendous impact in simplifying and improving sample storage conditions and requirements. The current work focuses on forensics analysis; however this technology is applicable to all endeavors requiring storage of DNA.     

应用DNA Typer15TM Direct试剂盒对河南地区汉族人群14个基因座遗传多态性的调查

目的调查河南地区汉族人群14个STR基因座的遗传多态性。同时简要介绍本实验室建库流程。方法应用DNA Typer15TM Direct试剂盒检测359名河南地区汉族无关个体14个STR基因座的等位基因频率,并应用统计软件计算群体遗传学参数。结果 14个STR基因座的基因型分布均符合Hardy-Weinberg平衡(P>0.05),14个基因座的杂合度(H)在0.694～0.922之间,匹配概率(Pm)在0.017～0.131之间,个人识别率(PD)在0.869～0.983之间,多态信息含量(PIC)在0.670～0.910之间,非父排除概率(PE)在0.418～0.841之间。结论 14个STR基因座在河南汉族人群中有较高的多态性,所得的群体遗传学数据可为法医学个人识别和亲子鉴定提供结果评估的依据。应用DNA Typer 15TM Direct试剂盒构建DNA数据库简单经济实用。     

A Simple and Efficient Method of Extracting DNA from Aged Bones and Teeth

DNA is often difficult to extract from old bones and teeth due to low levels of DNA and high levels of degradation. This study established a simple yet efficient method for extracting DNA from 20 aged bones and teeth (approximately 60 years old). Based on the concentration and STR typing results, the new method of DNA extraction (OM) developed in this study was compared with the PrepFiler? BTA Forensic DNA Extraction Kit (BM). The total amount of DNA extracted using the OM method was not significantly different from that extracted using the commercial kit (p > 0.05). However, the number of STR loci detected was significantly higher in the samples processed using the OM method than using the BM method (p < 0.05). This study aimed to establish a DNA extraction method for aged bones and teeth to improve the detection rate of STR typing and reduce costs compared to the BM technique.     

环氧乙烷消杀DNA污染效果初探

目的初探环氧乙烷消杀DNA污染的效果。方法收集98例分别含有唾液、皮屑、汗斑、毛发、血斑、肋软骨的法医物证样本,分两组进行环氧乙烷灭菌6h和8h,提取DNA后扩增,使用3130XL或3500XL测序仪检测进行STR分型。结果 EO 6h组44例样本中有2例口腔拭子检出阳性结果,EO 8h组54例样本中有1例毛发检出阳性结果,阳性样本STR图谱表明仅有少量DNA残留,其余生物样本未检测到STR图谱。结论环氧乙烷能有效消杀DNA污染,可适用于DNA检验耗材的灭菌。     

尿液中DNA的提取与检验

尿液中DNA的STR分型检验有一定的应用价值:国外文献报道过应用于运动员兴奋剂控制^[1]中可疑尿检样品的个体识别,国内则偶有案发现场提取到尿液、尿冰、尿斑并成功进行个体识别的案例报道。与血液、精斑、唾液等检材相比,尿液STR分型的检出率较低,主要是与尿液中的成份有关。本文重点分析人类尿液成分,分类总结目前可用于提取尿液中DNA的多种方法,分析可能影响尿液STR分型检验结果的因素。     

盗窃案件现场检材提取与DNA检测结果的统计分析

目的统计分析1574例盗窃案件中提取的2496个现场生物检材,为提高DNA在盗窃案件侦破中的应用成效提供参考。方法根据2496个生物检材的类型、现场提取方法、重点提取部位、DNA检测结果等进行统计和分析比较,总结常见类型盗窃案件现场生物检材的主要发现提取部位以及不同方法提取的现场生物检材DNA检出率。结果接触类检材已成为盗窃案件最多见的生物检材类型,但检出率仍然较低,对混合分型应进一步分析筛选以提高DNA的认定率;不同方法提取的现场生物检材在DNA检出率方面存在统计学差异,接触类生物检材以植绒拭子和原物提取的方式为首选;现场生物检材的主要发现提取部位根据盗窃案件的类型不同有所侧重。结论现场勘查人员在盗窃案件中发现和提取到有价值的生物检材是提高DNA检出认定能力的关键因素,应着力培养现场勘查人员的微量生物物证意识,提高现场勘查人员提取和处理微量生物检材的能力。     

Massively parallel sequencing and the emergence of forensic genomics: Defining the policy and legal issues for law enforcement

Use of DNA in forensic science will be significantly influenced by new technology in coming years. Massively parallel sequencing and forensic genomics will hasten the broadening of forensic DNA analysis beyond short tandem repeats for identity towards a wider array of genetic markers, in applications as diverse as predictive phenotyping, ancestry assignment, and full mitochondrial genome analysis. With these new applications come a range of legal and policy implications, as forensic science touches on areas as diverse as ‘big data’, privacy and protected health information. Although these applications have the potential to make a more immediate and decisive forensic intelligence contribution to criminal investigations, they raise policy issues that will require detailed consideration if this potential is to be realised. The purpose of this paper is to identify the scope of the issues that will confront forensic and user communities.     

Contribution to the Development of Guidelines in the Analysis of Biological Evidence in Sexual Assault Investigations

This investigation intends to study materials and techniques used for biological evidence collection in sexual assault cases and is divided into two stages: in stage one, methods for biological evidence collection (the single swab (including three variants) and the “double swab technique”) were compared; in stage two, swabs’ component material was compared. The sampling was composed of 42 heterosexual couples who provided mock samples. The collection methods in which the whole swab is covered by evidence presented significantly better outcomes (p < 0.001), such as the “double swab technique.” Additionally, nylon swabs proved to present significantly better features regarding the capacity of sample elution, providing significantly higher amounts of DNA (p ≤ 0.034). This study provides guidelines for better collection of biological evidence regarding the collection method using a swab and the proper swab material to utilize.