短波紫外照射对汗潜手印DNA检测的影响初探

目的探测短波紫外灯的照射是否会对汗潜手印DNA检测产生影响。方法由每名志愿者在纸张上捺印4枚拇指指印使每枚指印的脱落细胞量保持基本相同,抽取每名志愿者所捺印的一枚指印作为一组,共有四组,将三组指印置于短波紫外灯的照射下,照射时间分别设置为10min﹑30min和1h,还有一组不照射,然后用磁珠法对所有指印提取DNA并进行定量。结果短波紫外灯的照射会对汗潜手印中的DNA造成减损,照射时间越长,减损得越多。结论尽量减少短波紫外灯对汗潜手印照射的时间(可控制在10min内),以保证汗潜手印有足够量的DNA而能被用于STR分型检测。     

05式警用转轮手枪弹壳接触DNA检验方法的比较

目的比较05式警用转轮手枪弹壳表面接触性DNA检验方法,为实际检验提供参考和借鉴。方法制备40例击发后手枪弹壳的模拟样本,分别用两步转移法提取弹壳表面不同部位检材,采用两种DNA提取法和两种扩增试剂盒对样本进行STR分型检验,比较评价检验结果。结果避开发射药残留区域采用两步转移法提取样本,有助于提高检出率;Chelex-100联合Microcon-100法提取模板DNA的产量最高可达1.18ng,高于Mini M48试剂盒法(0.91ng);MiniFilerTM试剂盒的等位基因检出率(23.61%)高于IdentifilerTM试剂盒(6.41%)。结论采用选择适当区域提取检材,采用Chelex-100联合Microcon-100法提取DNA,经MiniFilerTM试剂盒扩增,进行弹壳接触DNA分型的效果较好。     

茚三酮显现汗潜指印的三种操作方法对DNA检测的影响

目的探讨并比较茚三酮显现汗潜指印的3种操作方法,即溶液浸泡法、涂抹法和喷雾法对后续DNA检测带来的影响。方法取16名志愿者的指印分4组,分为茚三酮浸泡法、涂抹法和喷雾法以及空白组,然后提取DlNA进行定量和STR分型检测。结果3种操作方法都会减少汗潜指印DNA的量,喷雾法的损失量最大,浸泡法和涂抹法结果比较接近。结论现场可疑指印检材,应根据检验需要决定指印显现和DNA提取的先后顺序。     

真空镀膜与“502”熏显法显现非渗透性客体上汗潜手印的比较研究

目的探索真空镀膜手印显现技术,提高现场潜在手印显现率。方法通过真空镀膜与＂502＂熏显法显现常见非渗透性客体上汗潜手印的对比实验,比较二者显现效果优劣。结果真空镀膜法对于显现常见非渗透性客体上的新鲜和陈旧汗潜手印都有着明显的优势。结论真空镀膜是一种更为灵敏的非渗透性客体手印显现方法,是现有手印显现方法的重要补充。     

3种提取胶带粘面汗潜指印中DNA的方法比较

目的比较胶带粘面汗潜指印中DNA提取的方法。方法分别采用硅珠法、QIAMicrokit法、硅珠-QIAMicrokit法提取胶带粘面的汗潜指印中DNA,STR复合扩增,荧光电泳检测。结果用QIAMicrokit法、硅珠-QIAMicrokit法提取胶带粘面汗潜指印中DNA,检测成功率分别为21%和36%。硅珠法检测未获成功。结论硅珠-QIAMicrokit法提取胶带粘面汗潜指印中的DNA比QIAMicrokit法,检验时间更短,检测成功率更高。     

M48磁珠法和Chelex-100法提取脱落细胞DNA的初步比较

目的对M48磁珠法和Chelex-100法提取脱落细胞DNA的检验效果进行比较,为优化提取方法提供参考。方法选取案件受理检材50例烟蒂、50例纺织物品、50例作案工具,根据不同条件分别用吸附法、沾附法获得DNA,采用磁珠法（M48）和Chelex-100法提取后,常规STR检测。结果烟蒂类检材采用2种方法提取DNA,所得结果没有明显差异;纺织物品和作案工具上脱落细胞DNA的提取采用M48磁珠法提取的效果明显优于Chelex-100法。结论相对而言,M48磁珠法更具优势。     

硝酸银、茚三酮、DFO法显现纸张上指印的效果比较

目的为有效的提高纸张上汗潜手印的显现率。方法根据汗潜手印的显现原理,针对不同的纸张,分别运用硝酸银、茚三酮与DFO（1,8-二氮芴-9-酮）3种显现方法进行了实验,并对实验结果进行了分析比较。重点分析了这3种方法在显现不同纸张、不同遗留时间、不同汗液量的汗潜手印时的效果及其适用范围。结果为改善渗透性客体上的汗潜手印显现效果,提供科学的依据。     

纸张上潜在手印三种前处理方法对DNA检验的影响

目的通过比较常见纸张上潜在手印盲提法与显现后精准提取法的接触DNA检出率,探讨常见纸张上接触DNA前处理的优选方案。方法比较五种常见纸张上使用盲提法和显现潜在手印(茚二酮显现法、茚三酮熏显法)后精准提取法采集的接触DNA样本检出率。结果粗糙日历纸盲提的接触DNA检出率为17.8%,通过茚二酮法和茚三酮法显现的潜在手印所提取的DNA检出率分别为75.6%、77.8%;光滑日历纸三种方法所提取的接触DNA检出率为4.4%、11.1%、11.1%;A4复印纸三种方法接触DNA检出率为20%、37.8%、66.7%;牛皮纸三种方法接触DNA检出率为20%、68.9%、64.4%;快递纸袋的三种方法接触DNA检出率为2.2%、6.7%、46.7%。结论不同纸张上潜在手印经显现后接触DNA检出率不同,通过茚二酮或茚三酮显示潜在手印后精准提取DNA的前处理方法相较于盲提法的接触DNA检出率高。实战中可应用此类方法同时获得手印与DNA分型,以有效提高证据力。     

卫生纸上汗潜手印显现方法比较研究

目的通过比较实验来探寻卫生纸上汗潜手印的最佳显现方法,为实际工作提供指导性建议。方法选择市面上常见的四种卫生纸,在每种卫生纸上制作汗潜指印实验样本,分别将茚三酮溶液浸泡法与茚二酮溶液浸泡法、茚二酮溶液浸泡法与茚二酮溶液超声雾化法、茚二酮溶液超声雾化法与(对)-二甲(替)氨基肉桂醛(DMAC)显现纸冷熏法、茚二酮溶液浸泡法与红外加热显现法、茚二酮溶液超声雾化后加热显现法与室温显现法进行两两比较,分析显现效果。结果茚二酮显现的灵敏度和质量均优于其他几种方法,特别是超声雾化后室温显现,既能很好地显现手印又不影响后期的DNA检验。结论采取茚二酮超声雾化室温条件显现方法显现卫生纸上的汗潜手印具有显现效果好、设备条件要求低、操作性强的特点,在实际案件中可以借鉴应用。     

荧光黄湿粉显现手印方法的初步研究

目的研发一种具有荧光特性的黄湿粉,以提取遗留在不同客体上的不同种类的手印。方法在100mL温水中加入适量的表面活性剂,溶解后加入100g荧光黄颜料,选用不同种类客体及不同种类物质手印进行显现实验,比较显现效果;结果遗留在光滑非渗透性客体及半渗透性客体表面的汗潜、油潜手印,显出的手印纹线流畅、反差强、荧光强;结论荧光黄湿粉可适用于光滑非渗透性客体及半渗透性客体表面新鲜或较新鲜汗潜手印、油潜手印及血潜手印的显现。     

国产磁珠Wawasye试剂盒在法医DNA中应用

目的探讨国产磁珠Wawasye试剂盒在法医DNA检案中的应用效果。方法利用475份各类常见生物检材测试其效果,并与M48磁珠试剂盒作比较。结果国产磁珠Wawasye试剂盒与M48磁珠试剂盒在检验各类常见生物检材的结果无显著性差异。结论国产磁珠Wawasye试剂盒适用于公安机关DNA实验室。     

A simple DNA extraction method for marijuana samples used in amplified fragment length polymorphism (AFLP) analysis

As a first step in developing a molecular method for the individualization of marijuana samples, we evaluated a plant DNA extraction kit. The QIAGEN plant DNeasy method uses a spin column format for recovery of DNA and is effective for obtaining high molecular weight DNA from leaf, flower (bud), and seed samples of marijuana. The average DNA yield was 125-500 ng per 100 milligrams of fresh plant tissue. The recovered DNA was of polymerase chain reaction (PCR) quality as measured by the ability to generate reproducible amplified fragment length polymorphism (AFLP) profiles. AFLP is a technique used to create a DNA profile for plant varieties and is being applied to marijuana samples by the authors to link growers and distributors of clonal material. The QIAGEN plant DNeasy method was simple, efficient, and reproducible for processing small quantities of marijuana into DNA.     

Evaluation of Two New Methods for DNA Extraction of “Legal High” Plant Species

A quick, simple, and high-yield nucleic acid isolation process is crucial for high-quality DNA analysis. The ability of the MicroGEM PDQeX phytoGEM system and Omega Bio-tek E.Z.N.A.® Plant DS Mini kit to extract PCR-ready DNA was evaluated by extracting the forensically relevant “legal high” plant species: Ipomoea purpurea, Artemisia absinthium, Mitragyna speciosa, Datura stramonium, and Papaver somniferum. The plant material was pulverized, processed using the manufacturer’s plant protocol for the PDQeX Nucleic Acid Extraction or the manufacturer’s protocol for the Omega extraction, quantified using the Invitrogen Qubit 2.0 Fluorometer, and analyzed for amplifiability by PCR using a Qiagen Rotor-Gene Q instrument and published assays. The DNA amplicons for the legal high species produced high-resolution melt curves concordant with the melts observed when DNA was isolated using the Qiagen DNeasy Plant Mini Kit in previous studies.     

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.     

24个Y-STR基因座在云南苗族人群中的序列多态性

目的研究法医学常用Y-STR基因座在中国云南苗族男性个体中的序列多态性。方法采用M48磁珠提取纯化试剂盒提取样本DNA,使用ForenSeqTM DNA Signature Prep试剂盒制备文库,Miseq FGx平台进行测序,ForenSeq Universal Analysis v1.2.1软件进行数据分析,用Arlequin v3.5软件计算各Y-STR基因座相关的统计学参数,将Y-STR基因座长度多态性与序列多态性进行比较。结果108名云南苗族个体中共检出106种单倍型,总体单倍型多样性(HD)和Y-STR分型系统的分辨能力(DC)分别为0.9993和0.9815。24个Y-STR基因座共检出204个基因,基因多样性(gene diversity,GD)值为0.2177~0.9481,15个Y-STR基因座的GD值大于0.6。DYF387S1、DYS390、DYS389II、DYS437、DYS438、DYS448、DYS612基因座存在长度相同的基因核心序列不同的情况。结论该24个Y-STR基因座在云南苗族男性人群中具有丰富的遗传多态性。研究结果可为Y-STR数据库的建立、群体遗传学和法医学实践提供参考。     

Recovery of DNA and fingerprints from touched documents

This study investigated the various factors affecting DNA profiling from DNA recovered from fingerprints deposited on paper before and after fingerprint enhancement treatments. The DNeasy^® plant mini kit (QIAGEN^®) was found to improve DNA recovery from paper by over 150% compared with the QIAamp^® mini kit. A significant decrease in the amount of DNA recovered was observed following treatment with DFO and/or Ninhydrin. This decrease in yield did not have a comparably significant effect on the quality of the SGM Plus™ profiles. Furthermore, this study found that whilst certain paper types, such as newspaper, magazine and filter paper allowed for the good recovery of DNA, common office paper and white card, strongly interfered with the recovery of DNA resulting in poor quality profiles.     

Comparison of Commercial Kits for Recovery and Analysis of Bacterial DNA From Fingerprints

In forensic science, fingerprints are a common source of evidentiary information. However, latent examination is not always successful and trace human DNA cannot always be obtained. Thus, examining the fingerprint microbiome may offer a suitable alternative to more traditional methods of forensic identification. The Zymo Research ZR Bacterial/Fungal DNA MicroPrep™ Kit, Qiagen QIAmp^® DNA Mini Kit, Promega Wizard^® Genomic DNA Purification Kit, and the MPBio FastDNA^® Spin Kit were compared for their ability to yield a sufficient amount of bacterial DNA for next-generation sequencing in order to obtain a microbiome profile. Prints were deposited onto slides, allowed to sit for up to 1 month, and total DNA isolated and quantified using each kit. The kit from Zymo Research yielded the most concentrated DNA sample (0.0084 ng/µL) in the least amount of time as compared to other kits examined. Although this amount of DNA was far below the recommended DNA concentration threshold recommended for next-generation sequencing, a microbiome profile was successfully obtained. As interest in using the microbiome of an individual as a forensic tool continues to increase, there is the possibility that the microbiome of a fingerprint could complement traditional human DNA profiling in the future. This study provides evidence that trace amounts of bacterial DNA from fingerprints is quantifiable and sufficient for microbiome analysis.     

STR-typing of human DNA from human fecal matter using the QIAGEN QIAamp stool mini kit

The purpose of this study was to compare the effectiveness of the QIAGEN QIAamp Stool Mini Kit against a standard phenolchloroform procedure for the extraction, quantitation, and STR-typing of human nuclear DNA from human feces. Stools from six subjects were sampled by swabbing and excision. Samples extracted with the QIAamp kit gave a wide range of DNA yields, whereas those extracted by the organic method yielded no DNA. DNA was not recovered from one subject's stools by either procedure. The QIAamp extracts were amplified with the Profiler Plus and COfiler kits, and PCR inhibition was observed with DNA extracts that were further concentrated. Substitution of water or TE-4 for the QIAamp elution buffer eliminated most, if not all, of the inhibition. A modified QIAamp procedure was used to extract thirty samples, which were subjected to one of five environmental conditions. DNA was recovered from all of these samples, and typing results were obtained on 93% of the samples.