Automated DNA casework workflow: A retrospective study of the first implementation of FIDL at the Netherlands Forensic Institute

FIDL is a fast and automated DNA identification line which represents a series of software solutions automating the process from raw capillary electrophoresis data to reporting. This retrospective study provides insight in the numbers of cases, turnaround time, results compared to the standard workflow and the benefits automation has in a large volume workflow.     

"Biological identikit": Development of a SNPs-panel for the analysis of forensic DNA phenotyping and ancestry

Personal identification in mass disasters and in crimes is essential for humanitarian, ethical and legal reasons. In these contexts, when individuals cannot be identified by standard forensic DNA analysis, the Forensic DNA Phenotyping and the analysis of the biogeographical ancestry could help. The aim of this study was to evaluate the potential of a new panel of 891 SNPs in predicting phenotypic traits and biogeographical origin to create a “biological identikit”. In addition to fresh biological material, old evidence found at the crime scene or extracted and long-term stored DNA were tested with 41 SNPs for phenotyping and 850 SNPs for ancestry. All the SNPs were successfully incorporated into a single two-step multiplex PCR reaction using the IonAmpliSeq ™ Library Plus and applied for massive parallel sequencing with the Ion S5 platform using up to 0.05 ng/µL of DNA. The analysis of the results was carried out with an in-house predictive algorithm and consulting 20 population databases. By comparing the results obtained with identikit or video-photographic surveys, it was possible to predict phenotype and ancestry with an accuracy greater than 90%. While these new markers cannot identify a specific individual, they can be a valuable investigative tool.     

Comparison of operational DNA recovery methods: Swabs versus tapelifts

It is routine among many jurisdictions to recover DNA using tapelifts on porous substrates (e.g. clothing) and swabs on non-porous substrates (e.g. tool handles). Here, we examine this by comparing the efficiency of the NSW jurisdiction’s specific swabbing and tapelift techniques on a range of porous and non-porous substrates. To test DNA recovery efficiency, 30 μl aliquots of 1:50 and 1:100 saliva dilutions were deposited onto the substrates, left to dry overnight, recovered, extracted, quantified and a subset profiled. Tapelifts recovered more DNA and DNA profiles with more detectable alleles than swabs for both saliva dilutions on porous substrates. For non-porous substrates, similar DNA quantities and profiles were generally recovered with both methods for both saliva dilutions. These data underpin current practices to recover DNA using tapelifts for porous substrates and swabs for non-porous substrates. These data also revealed severe degradation of DNA recovered from brass, supporting the on-going need to improve DNA recovery and analysis methods for brass substrates.     

Test of chlorine wipes for efficient removal of DNA from forensic genetics laboratories

Sodium hypochlorite is an efficient reagent for removal of unwanted DNA from laboratory surfaces. Here, we tested two different chlorine wipes and compared their performance to a 0.9–1.8% hypochlorite solution. WipeClean Chlorine Disinfection wipes contain > 0.1 g sodium hypochlorite/kg, whereas WetWipe Chlorine Desinfection wipes contain > 1000 ppm active chlorine. Clean surfaces were contaminated with 10 µL 0.5 ng/µL of massively parallel sequencing libraries. The DNA was dried and left for 45 min before any treatment. The surfaces were cleaned using either 1) a 0.9–1.8% hypochlorite solution and clean wipes, 2) a WipeClean wipe, 3) a WetWipe, or 4) the surface was not cleaned. All experiments were repeated three times. Subsequently, the surfaces were swabbed using cotton swabs. DNA was extracted from the swabs and the DNA concentrations were determined in quadruplicates by real-time PCR. This protocol was repeated after the soft plastic wrapping around the wipes were left open or closed for several weeks. The results showed that the WipeClean wipes efficiently removed DNA for up to four weeks after the box with the wipes were opened, whereas the WetWipe wipes dried faster and gradually lost their cleaning effect.     

鞋内底不同部位接触DNA提取初探

目的探讨鞋内底不同部位接触DNA提取检出率。方法取100名20-30岁的志愿者，将其穿用过的运动鞋和皮鞋鞋垫设置成不同穿用时间组、不同材料鞋垫组、穿用后不同放置时间组，根据脚的形态学及运动力学特点，将鞋垫分成8个区域进行脱落细胞提取，并进行DNA进行检验。结果鞋垫上8个不同区域提取到的脱落细胞DNA分型检验效果不同。足弓外侧区（足引折弓除外）的接触DNA检出率最高；足弓内侧、第1趾骨区、第1跖骨区及足跟区次之；第2～5趾骨区、第2～3跖骨区、第4～5跖骨区不容易成功提取到接触DNA。结论鞋内底接触DNA检出率与接触时间、放置时间、鞋垫材质均相关，分区提取检验DNA更有针对性。     

A discussion of the merits of random man not excluded and likelihood ratios

DNA mixture interpretation is undertaken either by calculating a LR or an exclusion probability (RMNE or its complement CPI). Debate exists as to which has the greater claim. The merits and drawbacks of the two approaches are discussed. We conclude that the two matters that appear to have real force are: (1) LRs are more difficult to present in court and (2) the RMNE statistic wastes information that should be utilised.     

用随意扩增的DNA多态性鉴定中国分离的部分旋毛虫虫株

以旋毛虫（Ｔｒｉｃｈｉｎｅｌａｓｐｉｒａｌｉｓ）国际标准虫种作对照，利用随意扩增的ＤＮＡ多态性技术对国内的部分旋毛虫分离株进行了鉴定与分析。经５条引物的单扩增及复合扩增结果显示，中国的旋毛虫猪株为Ｔ．ｓｐｉｒａｌｉｓ，犬株为Ｔ．ｎａ－ｔｉｖａ，猫株为Ｔ．ｎｅｌｓｏｎｉ。     

对刑事司法程序视野下DNA证据的探讨

DNA证据在刑事司法程序中有着独特的自身价值，但这并不意味着DNA证据就是完美无缺的“证据之王”。在当前我国的刑事司法领域中，关于DNA的鉴定和证据适用等方面还存在着诸多的问题。因此，我国应在DNA证据采信等环节上建立和完善相应规则，克服对DNA证据的盲目轻信。     

天津市法医DNA数据库的应用与发展

建立的天津市法医DNA数据库系统 ,将DNA分析技术的高效性与计算机系统的储存、高效检索的功能有机结合 ,实现了从受案到结案及建库的全程标准化、规范化、网络化管理。该系统启用一年多以来 ,为本地区侦查机关提供了百余起案件的破案线索 ,在多起重特大刑事案件的串并侦破中发挥了关键作用 ,技术破案率明显提高     

荆州地区汉族人群9个STR基因座多态性及法医学应用

本文选择Promega公司的3个复合扩增系统对荆州地区汉族人群进行了基因频率调查,获得了9个STR基因座的群体遗传学参数,报告如下。1材料与方法1.1实验材料1.1.1样本146例汉族无关个体血样来自荆州市各县市区,系本实验室日常检案积累。1.1.2主要仪器设备eppendorf-5331型扩增仪(eppendorf公司);model-4001型电泳仪及SA-32型电泳槽(GIBCO公司)。1.1.3主要试剂Chelex-100(Bio-Rad公司);Taq酶(Promega公司);3个复合扩增试剂盒(Promega公司)。1.2实验方法1.2.1模板DNA的制备所有血样均用5%chelex-100快速提取DNA。1.2.2复合扩增扩增总体…