如何发现和提取泥土上的血痕

一、如何发现泥土上遗留的隐蔽血痕首先要详细了解案情。通过访问及现场调查,了解受害人被发现时所处的位置,包括方向、体位及有无衬垫物品等。根据案情介绍,分析现场地面或墙壁上是否遗留有血迹及可能遗留的部位,做到心中有数。其次要仔细勘查现场。根据现场状况,结合案情介绍,确定中心现场,找出受害者当时所处的位置。结合损伤部位及损伤程度,推断出受害人当时的体位,以重点寻找可能遗留有血迹的部位,必要时可结合利用倒光进行寻找。发现可疑斑迹后,应立即保护起来,经拍照固定后提取。二、泥土上血痕的提取1.刮取法:适用于光滑、坚硬的地面或墙壁上的血痕或厚血痂。2.擦拭法:对于坚硬泥块上的血痕,取少许纱线(根据血痕量的多少而定),用生理盐水浸湿后,擦拭地面血痕,阴干待     

浸水潮湿血痕的DNA检验1例

1案例某日,本市一辆桑塔纳轿车在某医院门口抛下一具男尸逃离。第二天,该可疑车辆被发现,经勘查,该车后座布套呈潮湿状态,其上发现大量暗红色的血痕,侦查人员遂将其在太阳下进行曝晒后送检。笔者剪取9mm血痕,采用Chelex法提取DNA,分型检测未获结果。遂用硅珠法提取车布套上血痕36mm,用ABIProfilerPlus进行扩增,ABI3100型测序仪电泳,获得明确的分型检测结果,与死者心血DNA结果比对一致。2讨论在水中浸泡或洗涤过的血痕的DNA难以提取,主要是由于一些洗涤剂或去污剂等化学试剂能够溶解细胞膜、核膜,使细胞通透性增加,DNA从细胞中释放…     

氨基比林血痕预试验处理血痕后样本的DNA定量

目的：探讨氨基比林血痕预试验处理血痕后样本DNA含量的变化及对STR分型检测的影响。方法10名健康无关个体EDTA抗凝血液制成滤纸血痕,氨基比林血痕预试验检测,按试验后血样干燥保存时间分30 min、1 h、3 h、6 h、12 h、24 h共6个实验组,并采用磁珠法、QIAcube DNA纯化法、Chelex-100法三种方法提取样本DNA,应用荧光定量PCR检测样本DNA含量,PCR-STR荧光技术进行STR分型。结果提取方法相同时,氨基比林血痕预试验后血样随干燥保存时间的延长,样本DNA含量呈逐渐降低的趋势。保存时间相同时,不同DNA提取方法间,样本DNA含量差异也有统计学意义。90.56%样本均可获得16个STR基因座明确分型。结论氨基比林血痕预试验对血痕样本DNA有损伤,24 h内多可获有效STR分型。磁珠法提取样本DNA进行STR分型,效果最好。     

直接扩增法在血痕、肋软骨和唾液检材中的应用

目的采用Identifiler Direct PCR试剂盒直接扩增法进行棉签擦拭血痕、肋软骨和烟蒂唾液斑DNA分型检验,并评价其应用价值。方法收集棉签擦拭血痕、烟蒂各20份,肋软骨10份,采用Identifiler Direct PCR试剂盒进行直接扩增及分型检验,以相同检材采用磁珠法/Chelex-100法提取模板DNA后扩增检验结果作为对照,对两组所得结果进行比较分析。结果棉签擦拭血痕和肋软骨一次检测完整分型率均为100%,分型结果与对照组一致;烟蒂上唾液斑有2份检材第一次未能完整分型,调整方法再次检验后获分型成功。结论实际检案中的棉签血痕、肋软骨和烟上唾液斑,采用直接扩增法检测,方法简单、快速、稳定、检材用量小,可在实际检案中选择使用。     

联苯胺预试验处理血痕后样本DNA定量的研究

目的探讨联苯胺血痕预试验处理后样本DNA含量的变化及对STR分型检测的影响。方法选取10名无关个体EDTA抗凝血液制成滤纸血痕,保存干燥时间分0．5h、1h、3h、6h、12h、24h六个实验组,并采用磁珠提取法、QIAcubeDNA提取纯化法、chelex-100提取法提取样本DNA,应用RT-PCR定量技术检测样本DNA含量,同时应用PCR-STR技术和Idfiler-plus试剂盒检测相应样本STR分型。结果联苯胺血痕预试验后处理样本,随保存时间的延长,其样本DNA含量显示逐渐降低的趋势。回归线性对数分析显示,磁珠提取法：Y=-0．40871n（x）＋0．7044R0—0．7633;QIAcubeDNA提取纯化法：Y=-0．23931n（x）＋0．4764R0—0．8715;chelex-100提取法：Y=-0．11781n（x）＋0．2302R2=0．9571。不同DNA提取方法对同一保存时间的联苯胺血痕预试验试剂处理样本DNA含量间差异有极显著性,P〈O．01。结论联苯胺血痕预试验后对后续STR分型影响较大,联苯胺血痕预实验后的血痕不能继续进行STR分型检测。     

STR系统HUMCSF1PO-HUMTPOX-HUMTH01三位点复合扩增在法医学上的应用

STR系统是人类基因组中具有高度多态性的遗传标志系统，其DNA片段通常小于500hp，很容易通过PCR扩增并进行检测＼笔者参照美国Promega公司的HUMCSFIPO－HUMTPOOHUMTHVCTT）三位点复合扩增的方法，在对中国上海地区117例个体作了人群频率调查以后，逐步将该方法运用于血液。血痕、精斑的检验，在凶杀、强奸等刑案及亲子鉴定中起到了证据的作用。材料与方法样品取自刑案中涉及的活体血液150例、死者血液及血痕140例、精斑20例。一、DNA提取1．血液及血痕中的DNA提取取lml无菌水于1．5ml离心管，加入10pl血液或3mmZ血痕，小心…     

DNA检验破案1例

1案件简介 某年12月16日租居在某村的徐某（男,39岁）被人发现死在出租屋中。现场客厅及主卧室地上及墙上见多处喷贱状、滴状、擦拭状的半干涸血迹,主卧室西墙上血迹处涂料多处被刮擦,现场有清理变动的痕迹,尸检全身共有34处创口。提取死者、现场血迹及主卧室床单上斑迹等进行DNA检验。DNA检测结果：床单上检出死者徐某精子成分及另一男性A精子成分,厨房内一牙刷、主卧室里的拖鞋及客厅抽屉纸上点状血均检出A男成份，现场其余血迹为徐某所留。     

咀嚼后槟榔表面唾液斑DNA检验1例

1案例资料1.1简要案情某日,3名男子在公共场所寻衅滋事逃逸,警察在现场提取到遗留的3枚嫌疑人咀嚼过的槟榔,要求进行DNA分型。1.2 DNA检验样本处理3枚槟榔中2枚较干燥,表面纤维稀疏蓬松,直接剪取槟榔纤维;1枚表面相对潮湿,用无菌脱脂棉在表面进行擦拭。DNA提取及纯化将上述槟榔纤维和擦拭脱脂棉分别置于1.5mL EP管中,加1 000μL纯水清洗,离心,弃上清,保留约100μL液体和沉淀物;     

匹拉米洞与联苯胺在血痕预实验中的灵敏性及DNA损伤检测研究

目的血液痕迹是暴力犯罪现场最易遗留的一类痕迹,是法医学检验中最常见和最重要的一类物证。血痕预实验是利用化学检测的方法从现场大量分布的可疑斑迹中初步筛选可能是血痕的重要方法,是法医学鉴定的重要前提。本文比较匹拉米洞法和联苯胺法的灵敏度、对DNA-STR检验的影响以及对细胞核的损伤情况,以探索匹拉米洞法应用于血痕预实验的可行性。方法对新鲜全血进行梯度稀释,观察比较检测灵敏度;利用Chelex-100提取匹拉米洞、联苯胺等试剂预检后的血痕样本中的DNA,应用PCR-STR技术及荧光检测技术检测样本的STR分型,观察STR分型结果,比较两种方法对后续DNA-STR检验的影响;在细胞培养液中加入联苯胺、匹拉米洞,应用彗星电泳技术评价细胞核DNA的损伤。结果匹拉米洞法可检测的最低血红蛋白浓度为25μg/m L,灵敏度低于联苯胺法(5μg/m L);DNA-STR有效分型率为96.67%,远高于联苯胺法(18.09%);联苯胺组彗星尾长为52.40±9.21、尾距为43.29±4.85、尾部DNA含量为16.25±2.35,显著高于匹拉米洞组。结论匹拉米洞法可用于血痕预实验,对血痕中DNA的损伤、对DNA-STR分型的影响均低于联苯胺法,可替代联苯胺作为新的法医学血痕预实验方法。     

指甲擦拭物Y-STR检验在女性被杀案件中的应用

1案例 本市发生一起女性被害案件。现场遭到很大程度的破坏．通过混合斑等常规生物检材检测．均未得到有效证据。技术人员遂提取了死者指甲进行DNA检验。用双蒸水浸润的纱线擦拭被害人指甲内侧尖部．放入1．5mL离心管中．采用Chelex法提取检材基因组DNA，ldentifilerTM试剂盒（美国AB公司）复合扩增检测，结果在被害人的指甲擦拭物中检出含有微量     

Assessment of disputed identity of blood alcohol samples using DNA fingerprinting

DNA fingerprinting is a perfect tool for investigating the identity of disputed blood by alcohol samples extracted. However, blood samples stored at an ambient temperature for longer periods can show considerable degradation of high-molecular DNA, diminishing the value of fingerprint investigation because of loss of the less frequent bands formed by the longer DNA fragments. Addition of the complexing agent EDTA can retard this degradation. Determination of the sex with DNA probes in the blood alcohol sample increases confidence in the investigation.     

衍生化-液相色谱-质谱联用测定血中氟乙酸类杀鼠剂

目的建立血中氟乙酸类杀鼠剂衍生化-液相色谱-电喷雾离子阱质谱分析方法。方法血样经乙腈沉淀蛋白后离心,上清液中加入衍生化试剂α-溴苯乙酮和催化剂四丁基溴化铵,在60℃水浴中加热90min,衍生化产物直接进行液相色谱-电喷雾离子阱质谱联用分析。结果血中氟乙酸根浓度在0.15μg/mL～15.40μg/mL之间具有良好的线性关系,最低检出限为0.020μg/mL。结论本文建立的方法操作简便、灵敏、快速,适用于刑事案件中氟乙酸类杀鼠剂的快速检验。     

HPLC-UVD/FLD法测定血中氟乙酸类杀鼠剂

目的采用水相催化衍生化-液相色谱-紫外/荧光检测分析法,检测血中氟乙酸类杀鼠剂。方法血样经乙腈沉淀蛋白后,加入衍生化试剂4-溴甲基-7-甲氧基香豆素、催化剂四丁基溴化铵,在80℃水浴中衍生化反应120min,衍生产采用液相色谱-紫外/荧光检测分析。结果紫外检测法:氟乙酸根浓度在0.38～38.50μg/mL之间线性关系良好,最低检出限为0.10μg/mL;荧光检测法:氟乙酸根浓度在0.15～15.40μg/mL之间线性关系良好,最低检出限为0.050μg/mL。结论水相催化衍生化-液相色谱-紫外/荧光检测分析方法具有较好的灵敏度、准确性和精密度,可用于实际案例检测。     

DNA指纹图在法医学鉴定中应用的研究(Ⅱ)——应用‘Myo’小卫星探针进行血斑、精斑、个体组织的个体认定

应用‘Myo’小卫星 DNA 探针,Southern 印迹杂交技术,对血斑、精斑、同一个体不同组织进行 DNA 指纹图分析,均获得清晰的图谱。同一个体的血斑与血液、精斑与精液以及不同的组织其 DNA 指纹图谱完全相同。可以根据斑痕或组织与嫌疑个体的血液或某一组织 DNA 的指纹图谱比对以做出同一认定。50μl 血液量的血斑、5μl 精液量的精斑可以获得清晰易辨的指纹图谱。五年的精斑、两年的血斑亦可做出与同源个体新鲜精液、血液完全一致的 DNA 指纹图谱。对杀人、强奸杀人、碎尸等不同案件的血痕、精斑、不同组织碎块进行了 DNA 指纹图检验,均做出了正确的个体认定。本方法的应用为我国法医物证检验提供了新的分析手段,使个体认定得以实现。     

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。     

指甲花醌显现纸张上汗潜手印初步研究

目的介绍一种用天然植物提取成分指甲花醌显现渗透性纸张表面汗潜手印的方法。方法利用指甲花醌能够和手印遗留物质中的氨基酸发生显色反应来显现手印。结果显现出的手印纹线在自然光下观察呈紫褐色,并且在540nm激发光源条件下,通过红色护目镜观察还有很强的荧光特征。结论指甲花醌显现法具有安全性高、健康环保、操作简单、显现效果明显的特点。     

荧光STR直接复合扩增试剂缓冲体系的研制

目的研制适用于数据库样本荧光STR直接复合扩增体系。方法针对常规血卡、FTA和903血卡样本,配制扩增缓冲液基准母液,采用不同配方的扩增缓冲体系进行直接扩增及检测。考察不同种类增强剂、4种商业化DNA聚合酶、不同复性温度和终延伸时间对检材的检测效果,并验证优化体系的适应性。结果采用本文所建体系对各类血卡样本进行检验,均可获得样本清晰、完整的STR分型。体系选择BSA\Tween20\DMSO\甘油等增强剂组合、Typer热启动聚合酶1.5U/10μL、57～59℃复性温度、30～50min终延伸时间,采用10μL体系即可对直径1.2mm FTA卡血样进行有效分型。结论本文所研制的缓冲体系能够满足常规血卡、FTA和903血卡样本直接扩增检验的需要。     

Individual identification from semen by the deoxyribonucleic acid (DNA) fingerprint technique

For individual identification from semen, the deoxyribonucleic acid (DNA) fingerprint technique was used. In a blind trial, we succeeded in determining the semen donors among several volunteers comparing the DNA fingerprints of the blood and semen samples, respectively. Thereafter, we examined semen in a condom left beside a naked female dead body. The DNA fingerprint of the semen was recognized to be identical to that of the blood from a suspected man arrested later. This is the first report that the DNA fingerprint technique was practically used in a criminal investigation in Japan.     

Assessing three soil removal methods for environmental DNA analysis of mock forensic geology evidence

Soil is useful in criminal investigations as it is highly variable and readily transferred. Forensic geologists use several different techniques to removal soil from evidence prior to the analysis of inorganic components. There has been recent interest from the forensic science community to analyze environmental deoxyribonucleic acid (eDNA) associated with soil to augment existing forensic analyses. Notably however, limited research has been conducted to compare commonly used soil removal methods for downstream eDNA analysis. In this study, three soil removal methods were assessed: picking/scraping, sonication, and swabbing. Three mock evidence types (t-shirts, boot soles, and trowels) were sampled in triplicate with each removal method (n = 27). Soil samples underwent DNA isolation, quantification, and amplification of four genomic barcode regions: 16S for bacteria, ITS1 for fungi, ITS2 for plants, and COI for arthropods. Amplicons were prepared into libraries for DNA sequencing on an Illumina^® MiniSeq. DNA concentrations were highest in picked/scraped samples and were statistically significant compared with swabbed and sonicated samples. Amplicon sequence variants (ASVs) were identified, and removal methods had no impact on the recovery of the total number of target ASVs. Additionally, when assessing each sample in multidimensional space, picked/scraped samples tended to cluster separately from swabbed and sonicated samples. The soil core used a reference in this study also clustered with the picked/scraped samples, indicating that these samples may be more reflective of the communities collected from soil cores. Based on these data, we identified that picking/scraping is an acceptable soil removal method for eDNA analysis.     

Evaluation of DNA Extraction Methods for Processing Fingerprint Powder-Coated Forensic Evidence

In unison, fingerprinting and DNA analysis have played a pivotal role in forensic investigations. Fingerprint powders that are available on the market can come in a range of colors and with specific properties. This study evaluated the efficiency of DNA extraction from samples coated with 3 brands of fingerprint powders: Lightning, Sirchie, and SupraNano, covering a range of colors and properties. A total of 23 fingerprint powders were tested using the Chelex, Promega DNA IQ™, and Applied Biosystems™ PrepFiler™ DNA extraction protocols. The DNA IQ™ and PrepFiler™ methods extracted higher yields of DNA in comparison to Chelex, which also accounted for better quality of PowerPlex x00AE; 21 DNA profiles recovered. There were no signs of degradation or inhibition in the quantification data, indicating that samples returning low DNA yield was due to interference during DNA extraction and not PCR inhibition. DNA profiles were recovered from the majority of fingerprint powders with only a single powder, Sirchie Magnetic Silver, failing to produce a profile using any of the methods tested. A link was observed between the DNA extraction chemistry, fingerprint powder property, that is, nonmagnetic, magnetic and aqueous, and the brand of fingerprint powder. Overall, the DNA IQ™ method was favorable for nonmagnetic fingerprint powders, while magnetic fingerprint powders produced more DNA profiles when extracted with the PrepFiler™ chemistry. This study highlights the importance of screening DNA extraction chemistries for the type of fingerprint powder used, as there is not a single DNA extraction method that suits all fingerprint powder brands and properties.