"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.     

不同保存时间和不同精子数量精斑样本DNA分型比较

目的比较不同保存时间和不同精子数量精斑样本DNA分型的效果。方法制备精斑样本,保存10d的样本采用激光显微捕获30、20、15、10、5、1个精子,用于不同数量精子分型比较;保存10d、214d、375d的样本分别捕获30、20、10个精子,用于不同保存时间分型比较。比较各组检出率、等位基因丢失率和非特异性扩增率,采用χ2检验进行差异比较。结果①不同精子数量分型：捕获10个精子即可得到完整的DNA分型,且随着精子数增多,检出率逐渐提高而等位基因丢失率逐渐降低,30个精子等位基因丢失率为0%,1个精子则可达58.89%;②不同保存时间分型：总趋势是保存时间越短,捕获精子越多检出率越高,10个精子与20、30个精子组比较,均有显著性差异（P〈0.05）;等位基因丢失率及非特异性扩增率则随保存时间的延长而增加,相同保存时间的不同精子数量组之间和相同的精子数量的不同保存时间组之间比较,差异均具有统计学意义（P〈0.05）。结论激光显微捕获精子数目和检材保存时间对DNA分型结果有直接影响。     

技术创新领域的知识产权融资担保

知识产权质押是技术创新的知识产权融资担保方式，但其并不是技术创新知识产权融资担保的唯一担保方式。我国的技术创新知识产权融资担保中，有关知识产权融资担保操作程序和融资担保配套措施的法律有待完善。     

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。     

医疗事故罪认定之我见

医疗事故罪的认定,需要从犯罪的主体、主观方面、客观方面综合评定,并正确区分责任事故和技术事故。医疗事故鉴定结论在医疗事故罪的认定中有着重要的作用,但是医疗事故鉴定的程序、规则、组成人员等方面亟待改革。     

论检察委员会与办案组织关系的重新构建

新一轮检察体制改革给检委会和办案组织各自的发展带来了机遇和挑战,如何保障依法独立行使检察权与如何加强权力的监督制约已成为两者发展中共同面临的新课题。在此背景下,以往检委会和办案组织之间命令与执行的一元化关系已经不能适应新时期发展的需要,必须以检委会与办案组织相分离为基础,重新构建两者的多元化关系,为检委会和办案组织的发展提供新的空间和方向。     

四十九个命案诉讼失败的原因剖析

本文基于公安部刑侦局进行的第三次"剖析命案讲教训"活动,通过对全国各级公安机关上报的近几年四十九份诉讼失败命案卷宗的剖析得出几点教训:一是事实不清,证据不足;二是定性不准确;三是犯罪嫌疑人死亡或者有精神障碍;四是犯罪情节显著轻微,目的是切实提高命案侦办质量.     

DNA侦查技术的应用与前景

DNA侦查技术克服了以往遗传标记检测的种种缺陷以及指纹技术的一些局限 ,实现了物证检验从否定到认定的飞跃。目前DNA侦查技术正在走向更广阔、更深入的领域 ,出现了具有良好应用前景的一些新技术 ;许多国家均投资建立国家DNA犯罪数据库。我国的DNA犯罪数据库也在加紧建设中。从目前我国的有关情况看 ,建立DNA技术标准化和质量控制体系 ,已成为我国法庭科学亟待解决的问题。然而 ,DNA鉴定的不断完善 ,还有赖于人类基因组计划。