Typeability of AmpFlSTR SGM Plus loci in brain and thyroid gland tissue samples incubated in different environments

Autolysis and putrefaction are crucial factors responsible for degradation of cells, tissues, and organs. Postmortem changes may assume different course depending on extrinsic and intrinsic conditions. The aim of the study was assessment of environmental effect on typeability of AmpFlSTR SGM Plus loci: D3S1358, VWA, D16S539, D2S1338, D81179, D21S11, D18S51, D19S433, TH01, FGA, and gender marker amelogenin. Brain and thyroid gland tissue specimens collected during autopsies of five persons aged 20-30 years were incubated at 21 degrees C and 4 degrees C in different environmental conditions. DNA was extracted by organic method from tissue samples collected in 7-day intervals and subsequently typed using AmpFlSTR SGM Plus kit and ABI 310. A fast decrease in typeability rate was seen in specimens incubated in peat soil and in sand. Brain tissue samples were typeable in all AmpFlSTR SGM Plus loci within 126 days of incubation at 4 degrees C. Faster DNA degradation was recorded in thyroid gland specimens. In samples with negative genotyping results, no DNA was found by fluorometric quantitiation.     

Chelex-100法提取滤纸血痕DNA影响因素的比较

目的改进滤纸血痕DNA提取方法,建立更简便、廉价,适合当前DNA建库需要的提取方法。方法将752份滤纸血痕分成四组,分别按照四种不同的Chelex-100法进行DNA提取并进行比较研究;63份新鲜血痕分别按照两种方法提取并进行对比研究。结果对于陈旧滤纸血痕,四种提取方法的检测成功率无显著差异(P>0.05);对于新鲜血痕,两种提取方法的检测成功率有显著差异(P<0.05)。结论对于建库陈旧滤纸血痕样本的DNA提取可采用不加纯水处理,直接加入Chelex-100的方法进行。     

DNA含量变化与死亡时间推断的研究进展

在法医学实践中,死亡经历时间的推断具有重要的实践价值,但其准确推断却一直是法医学实践的难题,因而也一直是法医学研究的热点。法医DNA技术是近年来发展起来的在分子水平进行死亡时间推断的新技术、新方法,同传统方法相比,具有很大的优势,本文对该技术提出的背景、发展、优缺点以及发展前景进行综述,着重对DNA含量变化与其相关性的研究进展进行讨论。     

烧骨组织形态变化及DNA技术在个体识别中的应用

烧骨在火灾、焚尸、交通、爆炸等案件和事故的检材中具有特殊的地位。通过对不同条件焚烧下烧骨组织形态及DNA变化规律的研究,可为法医实践中烧骨的种属鉴定、性别及年龄判定提供准确的依据和标准,同时可利用残存的基因位点对烧骨残块进行个体识别和同一认定。烧骨DNA的提取方法及检测技术也在不断探索和改进。本文对烧骨在形态学、组织学和分子生物学水平研究进展以及烧骨评测的方法、技术进行概述,旨在为法医实践及进一步研究提供新的方法和思路。     

MiniSTR multiplex systems based on non-CODIS loci for analysis of degraded DNA samples

We describe two short amplicon autosomal short tandem repeat (miniSTR) quadruplex systems for eight loci D1S1171, D2S1242, D3S1545, D4S2366, D12S391, D16S3253, D20S161, and D21S1437, unlinked from the combined DNA index system (non-CODIS) loci, using newly designed primer sets. The results of an assay of 411 Japanese individuals showed that polymerase chain reaction (PCR) products within the eight loci were less than 150bp in size, without the seven additional bases for adenylation. The frequency distributions in the loci showed no deviations from Hardy-Weinberg equilibrium expectations. The accumulated power of discrimination and power of exclusion for the eight loci were 0.9999999991 and 0.998, respectively. For assay of highly degraded DNA, including artificially degraded samples and the degraded forensic casework samples assessed with the present miniSTR quadruplex systems, the systems proved quite effective in analyzing degraded DNA.     

PuriTyper~(TM)法医学纯化试剂盒的性能验证

目的验证PuriTyperTM纯化试剂盒各项性能指标和法医学应用价值。方法收集及制备抗凝血液、常见案件检材(唾液、烟头、精液、毛发、指甲、骨骼及组织块)、斑痕样本(血斑、唾液斑、精斑)以及模拟添加抑制剂和模仿自然环境中放置的血斑。采用PuriTyperTM纯化试剂盒提取纯化并进行DNA定量,IdentifilerTM复合扩增试剂盒扩增,产物经ABI 3130遗传分析仪进行检测,Genemapper软件分析结果,对该试剂盒灵敏度、稳定性、重复性、检材适应性进行测试。结果采用该试剂盒提取0.1～40μL血液分别获得0.042～26.45ng/μL的DNA。3种斑痕样本DNA产量平行试验结果稳定。不同类型检材重复检验所获IPC的CT平均值在27.60至28.03之间。常见案件检材所得分型与已知结果均一致。结论 PuriTyperTM纯化试剂盒能够满足法医DNA检验的要求,对法医学实践具有重要的应用价值。     

法医DNA标准物质备选细胞STR等位基因片段长度的定值

目的 研究建立法医DNA标准物质备选细胞基因组STR基因座等位基因片段长度标准定值的方法.方法 利用有机法提取HPF和HSSM细胞基因组DNA并进行STR复合扩增,将产物进行电泳检测.利用Gene Mapper软件分析电泳结果,记录STR基因座等位基因的数值,并对目前我国公安系统应用较为广泛的DNATyperTM15、IdentifilerTM两种试剂盒扩增产物进行相应的DNA片段长度(bp)统计以及定值.结果 HPF为男性个体细胞,HSSM为女性个体细胞.HPF和HSSM细胞DNATyperTM15系统等位基因片段长度范围分别为126.26±0.05～367.53±0.20bp和125.33±0.07～370.08±0.17bp,IdentifilerTM系统等位基因片段长度范围分别为117.22±0.04～340.02±0.08bp和117.21±0.03～323.86±0.09bp.结论 对STR基因座等位基因片段长度进行标准定值,可为法医DNA标准物质提供有效的溯源途径.     

Comparison of two methods for isolating DNA from human skeletal remains for STR analysis

Abstract: The quality and efficiency of a standard organic DNA isolation method and a silica‐based method using the QIAGEN Blood Maxi Kit were compared to obtain human DNA and short tandem repeats (STRs) profiles from 39 exhumed bone samples for paternity testing. DNA samples were quantified by real‐time PCR, and STR profiles were obtained using the AmpFlSTR^® Identifiler^® PCR amplification kit. Overall, the silica‐based method recovered less DNA ranging from 0 to 147.7 ng/g (average 7.57 ng/g, median = 1.3 ng/g) than did the organic method ranging from 0 to 605 ng/g (average 44.27 ng/g, median = 5.8 ng/g). Complete profiles (16/16 loci tested) were obtained from 37/39 samples (95%) using the organic method and from 9/39 samples (23%) with the silica‐based method. Compared with a standard organic DNA isolation method, our results indicate that the published silica‐based method does not improve neither the quality nor the quantity of DNA for STR profiling.     

Forensic Analysis of mtDNA Haplotypes from Two Rural Communities in Haiti Reflects Their Population History

Abstract: Very little genetic data exist on Haitians, an estimated 1.2 million of whom, not including illegal immigrants, reside in the United States. The absence of genetic data on a population of this size reduces the discriminatory power of criminal and missing‐person DNA databases in the United States and Caribbean. We present a forensic population study that provides the first genetic data set for Haiti. This study uses hypervariable segment one (HVS‐1) mitochondrial DNA (mtDNA) nucleotide sequences from 291 subjects primarily from rural areas of northern and southern Haiti, where admixture would be minimal. Our results showed that the African maternal genetic component of Haitians had slightly higher West‐Central African admixture than African‐Americans and Dominicans, but considerably less than Afro‐Brazilians. These results lay the foundation for further forensic genetics studies in the Haitian population and serve as a model for forensic mtDNA identification of individuals in other isolated or rural communities.     

Personal identification of cold case remains through combined contribution from anthropological, mtDNA, and bomb-pulse dating analyses

In 1968, a child's cranium was recovered from the banks of a northern Canadian river and held in a trust until the "cold case" was reopened in 2005. The cranium underwent reanalysis at the Centre for Forensic Research, Simon Fraser University, using recently developed anthropological analysis, "bomb-pulse" radiocarbon analysis, and forensic DNA techniques. Craniometrics, skeletal ossification, and dental formation indicated an age-at-death of 4.4 ± 1 year. Radiocarbon analysis of enamel from two teeth indicated a year of birth between 1958 and 1962. Forensic DNA analysis indicated the child was a male, and the obtained mitochondrial profile matched a living maternal relative to the presumed missing child. These multidisciplinary analyses resulted in a legal identification 41 years after the discovery of the remains, highlighting the enormous potential of combining radiocarbon analysis with anthropological and mtDNA analyses in producing confident personal identifications for forensic cold cases dating to within the last 60 years.