Recovery of DNA from bone without demineralization

This study assessed the performance of five different DNA extraction methods for the recovery of DNA from bone: ChargeSwitch® gDNA Plant Kit, DNA IQ™ System Kit, DNeasy® Blood & Tissue Kit, PrepFiler® BTA Forensic DNA Extraction Kit and phenol-chloroform-isoamyl alcohol. DNA was extracted from pig rib and femur bones that was fresh, had undergone surface decomposition for three months, and had undergone surface decomposition for one year. Extracted DNA was analyzed using real-time PCR and amplification of an in-house PCR multiplex that assessed the quality and quantity of DNA and for the presence of inhibitors. The phenol-chloroform-based method consistently yielded the highest amounts of DNA and DNA IQ the lowest; however, all methods produced relatively high yields of DNA from both pig rib and femur samples that could be amplified without any detected inhibition. The data demonstrate that with reasonable quality bone samples any of the tested methods can isolate DNA that can be successfully analyzed. The effective use of internal PCR controls is also demonstrated.     

STR genotyping of DNA extracted from used Triage kits

This study examined whether short tandem repeat (STR) genotyping can be performed using DNA remaining in Triage kits used to screen for drugs of abuse in urine. STR genotyping was successful for 15 loci using 12 kits stored for 1–6 months at room temperature. These results suggest that STR genotyping for human identification can be performed using DNA extracted from used Triage kits.     

Vacuum collection of gunpowder residues from clothing worn by shooting suspects, and their analysis by GC/TEA, IMS, and GC/MS

Experiments were conducted to collect gunpowder (propellant) residues from shooters' clothing by vacuum and to analyze them by gas chromatography/thermal energy analyzer (GC/TEA), ion mobility spectrometry (IMS), and gas chromatography/mass spectrometry (GC/MS). The residues were collected on fiberglass and Teflon filters using the portable vacuum sampler, all supplied with the IMS instrument. Several solvents were examined for the extraction of the propellant components from the filters. The extracts were centrifuged and/or filtered, concentrated by evaporation, and analyzed without any additional clean-up procedure. Based on the results of the study, an operational method for analysis of gunpowder residues was introduced into casework without changing the present operational technique for gunshot (primer) residue (GSR) analysis on clothing implemented by the Israel Police. In the modified method, the clothing is first sampled by double-side adhesive-coated aluminum stubs (the tape-lift method) for GSR analysis (the existing method), followed by vacuum collection for propellant residue examination. The issue of interpretation of the analytical results is discussed.     

刑事现场188份接触DNA检材法医学检验分析

目的分析188份接触DNA检材的提取、送检和检验结果,探讨接触DNA检出率及可能影响接触DNA检验的因素。方法收集本辖区2016年1月至2016年10月提取并送检的188份接触DNA检材,按照检材载体性质、提取方法、送检时间、检出率等进行分类,采用SPSS13.0软件对数据进行统计分析和χ2检验。结果188份接触DNA检材成功进行STR分型的有38份,检出率为20.21%;其中表面质软、粗糙的载体接触DNA检出率58.82%,高于其它载体接触DNA检出率组的差异具有统计学意义;直接原物提取的接触DNA检材检出率42.11%,高于脱落细胞粘取器提取、棉签拭子转移提取的检出率组的差异具有统计学意义;送检时间早的检材检出率高于送检时间晚的检材组且具有统计学意义。结论接触DNA检材的检出率受载体性质、提取方法、送检时间等因素影响,日常现场勘查时要注重发现检出率高的载体上的接触DNA选择适当的方法提取,并及时送检。     

Trace DNA: a review,discussion of theory,and application of the transfer of trace quantities of DNA through skin contact

Advances in STR PCR DNA profiling technology allow for the analysis of minute quantities of DNA. It is frequently possible to obtain successful DNA results from cellular material transferred from the skin of an individual who has simply touched an object. Handling objects, such as weapons or other items associated with a crime, touching surfaces, or wearing clothing, may represent sufficient contact to transfer small numbers of DNA bearing cells, or trace DNA, which can be successfully analyzed. With this minimal amount of contact required to yield a suspect profile comes tremendous crime solving potential, and a number of considerations for prudent application, and the maximization of evidentiary value. Evidentiary materials not previously considered must be recognized and preserved, and the resulting DNA type profiles interpreted in their proper forensic context.     

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.     

DNA Preparation from Sexual Assault Cases by Selective Degradation of Contaminating DNA from the Victim

Abstract:  The standard method to purify sperm DNA from vaginal swabs taken from rape victims is to selectively digest the victim's epithelial cells to solubilize the victim's DNA, and then separate the soluble DNA from the intact sperm by centrifugation. A different approach to removing the soluble victim's DNA is to selectively degrade it using a nuclease, DNase I. DNase I reduces the amount of soluble DNA by over 1000-fold, while having virtually no effect on the sperm DNA remaining in the sperm head and inaccessible to the enzyme. Nuclease inactivation and sperm lysis then yield a soluble, pure male DNA fraction. An aliquot of soluble DNA is removed prior to nuclease addition to provide the victim's fraction. Vaginal swabs taken at defined time points following consensual sex and taken from rape victims were processed using the nuclease method or the standard method and the nuclease method gave superior short tandem repeat profiles.     

无比对样本的STR混合分型分析策略

目的充分利用数据库的比对功能,指导无比对样本混合分型的分析、数据库比对和比对结果的筛选。方法使用联合包含概率描述混合分型的识别力。利用联合被包含概率来估计被混合分型包含的样本的可靠性。结果混合分型的联合包含概率小于10~(-7)时具备入库比对的价值。混合分型单个基因座上能确定的等位基因大于等于2个时,增加一个额外等位基因,不会过多降低识别力。数据库检索获得多个无容差比中结果后,可以根据联合被包含概率来进行排序,快速找到最有价值样本。     

Sex determination by PCR analysis of DNA extracted from incinerated, deciduous teeth.

Establishing the biological sex of human remains is a very important part of identifying victims of fire when severe soft tissue destruction has occurred. Deciduous (children's) teeth were exposed to a range of incineration temperatures 100-500 degrees C for 15 minutes. Polymerase Chain Reaction (PCR) amplification was used to identify specific human amelogenin regions. There was successful identification of human biological sex, from deciduous teeth exposed to incineration temperatures of 200 degrees C and below, using standard ethidium bromide gel staining. There was greater sensitivity using fragment analysis by laser induced fluorescence which achieved sex identification from some teeth heated to 400 degrees C.     

A comparative study of two extraction methods routinely used for DNA recovery from simulated post coital samples

In sexual assault cases DNA profiling of spermatozoa can be of critical importance. Most methods use differential extraction of the spermatozoa to separate it from the female component. Here we have compared two commercially available differential extraction methods, the QIAamp^® DNA mini kit (Qiagen) and Differex™ with the DNA IQ^® System (Promega). Simulated postcoital samples were prepared using buccal cells from a female donor and spermatozoa from three male donors. A dilution series ranging from neat semen to a 1:1500 dilution (semen:dH₂O) was prepared and mixed with an equal volume of saliva from a female donor. Extraction efficiency was assessed using DNA concentration measured with NanoDrop 2000 and Quantifiler^® Human DNA Quantification Kit and the profile count of full, partial and mixed DNA profiles generated using SGM Plus and PowerPlex^® ESI 17. Statistical analysis was carried out using Randomisation in R, which is a robust model making no assumption of the distribution of data. Based on the amount of DNA extracted and the types of profiles no significant difference in the performance of the two extraction kits was seen. However, the processing time taken with the Differex™ System was about half than that of the QIAamp^® DNA mini kit and involved fewer liquid transfers.     

DNA IQ磁珠法结合Maxwell~（TM） 16自动仪提取接触DNA

目的研究DNA IQ磁珠法结合MaxwellTM 16自动仪对接触DNA提取的应用价值。方法 151份案件接触DNA检材95℃裂解后,采用DNA IQ磁珠法结合MaxwellTM 16自动仪提取DNA,然后进行DNA定量和STR分型检测,统计各种类型的接触DNA含量I、PC CT值和STR分型成功率。结果 151份案件接触DNA检材中,除果核平均DNA获得量为9.51ng以外,其它接触检材的平均DNA获得量均大于10ng,烟蒂检验成功率最高为93%,果核检验成功率较低,为60%。所有DNA样品的IPC CT值均在27左右,纯度高。结论大部分接触DNA检材采用DNA IQ磁珠法结合MaxwellTM 16自动仪可提取到足以进行STR分型的DNA。     

An Optimized DNA Analysis Workflow for the Sampling,Extraction, and Concentration of DNA obtained from Archived Latent Fingerprints

DNA profiles have been obtained from fingerprints, but there is limited knowledge regarding DNA analysis from archived latent fingerprints—touch DNA “sandwiched” between adhesive and paper. Thus, this study sought to comparatively analyze a variety of collection and analytical methods in an effort to seek an optimized workflow for this specific sample type. Untreated and treated archived latent fingerprints were utilized to compare different biological sampling techniques, swab diluents, DNA extraction systems, DNA concentration practices, and post‐amplification purification methods. Archived latent fingerprints disassembled and sampled via direct cutting, followed by DNA extracted using the QIAamp® DNA Investigator Kit, and concentration with Centri‐Sep? columns increased the odds of obtaining an STR profile. Using the recommended DNA workflow, 9 of the 10 samples provided STR profiles, which included 7–100% of the expected STR alleles and two full profiles. Thus, with carefully selected procedures, archived latent fingerprints can be a viable DNA source for criminal investigations including cold/postconviction cases.     

二次消化结合磁珠法提取腐败组织DNA

目的 研究二次消化结合磁珠法对3种腐败组织DNA的提取效果.方法 采用二次消化结合磁珠法对用常规磁珠法提取DNA失败的91例高度腐败尸体的软骨、指(趾)甲、关节囊组织提取DNA,QuantifilerTM试剂盒进行DNA定量,用SinofilerTM或MinifilerTM试剂盒进行STR检测分型. 结果 91例高度腐...     

Characterisation and discrimination of so-called metallised fibres found in clothing and decorative materials originating from the consumer market

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Utility validation of extraction of genomic DNA from hard tissues, bone and nail, using PrepFiler™ Forensic DNA Extraction Kit

STR profiling using hard tissues obtained from a severely decomposed body is sometimes a laborious work. There is now on a market a new DNA extraction kit, PrepFiler™ Forensic DNA Extraction Kit (AppliedBiosystems), and we tested it for missing persons. Postmortem intervals ranged from weeks to several years. Fifteen bone fragments and eleven nails were used in this report. Genomic DNA was quantified by QuantiFiler^® DUO Quantification Kit (AppliedBiosystems), and STRs were analyzed using AmpFlSTR^® Identifiler^® PCR Amplification Kit (AppliedBiosystems). The profiling of 16 STR loci was successful in all nail samples. However, STR profiling was successful in only 6 of 15 bone materials. Nine cases failed to analyze STR polymorphisms using another DNA extraction kit, the QIAamp DNA Mini Kit (QIAGEN). For bone samples, it seems that STR profiling depends on the quality of samples.     

Obtaining forensic value from the cbWndExtra structures as used by Windows Common Controls,specifically for the Editbox control

The Windows Common Controls is a library which facilitates the construction of GUI controls commonly used by Windows applications. Each control is an extension of the basic ‘window’ class. The difference in the extension results in one control over another; for example, an Edit control as opposed to a Button control. The basic window class is documented by Microsoft and the generic information about a Window can be extracted, but this is of very limited use. There is no documentation and very little research into how these extensions are laid out in memory. This paper demonstrates how the extension bytes for the Edit control can be parsed leading to identification of previously unobtainable data which reveal information about the state of the control at runtime. Most notably, the undo buffer, that is, text that was previously present in the control can be recovered – an aspect which traditional disk forensics would simply not provide. The paper explains why previous attempts to achieve similar goals have failed, and how the technique could be applied to any control from the Windows Common Controls library.     

A comparison of penetration and damage caused by different types of arrowheads on loose and tight fit clothing

Bows and arrows are used more for recreation, sport and hunting in the Western world and tend not to be as popular a weapon as firearms or knives. Yet there are still injuries and fatalities caused by these low-velocity weapons due to their availability to the public and that a licence is not required to own them. This study aimed to highlight the penetration capabilities of aluminium arrows into soft tissue and bones in the presence of clothing. Further from that, how the type and fit of clothing as well as arrowhead type contribute to penetration capacity. In this study ballistic gelatine blocks (non-clothed and loose fit or tight fit clothed) were shot using a 24 lb weight draw recurve bow and aluminium arrows accompanied by four different arrowheads (bullet, judo, blunt and broadhead).The penetration capability of aluminium arrows was examined, and the depth of penetration was found to be dependent on the type of arrowhead used as well as by the type and fit or lack thereof of the clothing covering the block. Loose fit clothing reduced penetration with half of the samples, reducing penetration capacity by percentages between 0% and 98.33%, at a range of 10 m. While the remaining half of the samples covered with tight clothing led to reductions in penetration of between 14.06% and 94.12%.The damage to the clothing and the gelatine (puncturing, cutting and tearing) was affected by the shape of the arrowhead, with the least damaged caused by the blunt arrowheads and the most by the broadhead arrows. Clothing fibres were also at times found within the projectile tract within the gelatine showing potential for subsequent infection of an individual with an arrow wound.Ribs, femur bones and spinal columns encased in some of the gelatine blocks all showed varying levels of damage, with the most and obvious damage being exhibited by the ribs and spinal column.The information gleaned from the damage to clothing, gelatine blocks and bones could potentially be useful for forensic investigators, for example, when a body has been discovered with no weapons or gunshot residue present.