宁夏回族人群4个miniSTR基因座遗传多态性

在法医DNA检验中,miniSTR分型技术的使用有利于高度降解DNA样本或微量检材检测成功率的提高[1-2]。本文采用荧光标记复合扩增和毛细管电泳分析技术,对中国宁夏回族群体D6S474、D20S482、D4S2408和D6S1017基因座进行群体遗传学调查,以期为相关研究和实践提供基础数据。     

D20S161和D8S384两个基因座在法医学中的应用

评估D2 0S16 1和D8S384两个基因座在法医学中的应用价值。用自制的D2 0S16 1和D8S384两个DNA分型试剂盒 ,对人血、人精液、人唾液、动物血、人血与动物血的混合检材和人血痕、人精液斑、人唾液斑、动物血痕、人血与动物血的混合斑痕检材 ,以及陈旧血痕检材进行检测分型 ,并用这两个基因座PCR引物序列与DNA数据库进行联网对比分析。自制的D2 0S16 1和D8S384两个DNA分型试剂盒能对人血、人精液、人唾液、人血与动物血的混合检材分型 ,而动物血没有PCR产物 ;自制的D2 0S16 1和D8S384两个DNA分型试剂盒能对人血痕、人精斑、人唾液斑和人血与动物血的混合斑痕检材正确分型 ,而动物血痕没有PCR产物 ;斑痕检材分型结果与对应体液检材分型结果无差异 ;5 0份陈旧血痕检材全部获得阳性分型结果。DNA数据库联网比较提示 ,D2 0S16 1和D8S384基因座引物除了能与各自的模板序列发生特异性扩增外 ,理论上不能与DNA数据库中 6 0 6 36 4种已知序列产生PCR产物。D2 0S16 1和D8S384两个基因座具有高度的种属特异性 ,抗污染能力强 ,不易受降解的影响 ,是解决法医现场生物检材个人识别和亲子鉴定的理想手段     

两组引物对无毛囊毛根的PCR-STR分型

目的了解无毛囊毛根的短扩增子引物和通用引物PCR-STR分型在法医实践中应用的可行性。方法应用5对Bulter设计的短扩增子引物D8S1179、D21S11、THO1、D16S539和VWA与其对应的STR通用引物,利用非变性PAGE,对无毛囊毛根进行PCR-STR分型的对比研究。结果短扩增子引物与通用引物对无毛囊毛根分型的正确率:D8S1179为11.4%和17.1%、D21S11为3.7%和5.9%、vWA为22.2%和33.3%、THO1为9.3%和5.6%、D16S539为0和9.2%。毛根的短扩增子引物和通用引物部分STR分型出现了干扰结果的Ladder-like背景条带。结论在对无毛囊毛根检材进行通用引物和短扩增子引物PCR-STR分型时,五个STR位点分型检测的成功率有限,还需注意Ladder-like条带的干扰。     

STR复合扩增及荧光检测技术在个体识别中的应用

目的 :使用 310型遗传分析仪对D3S1358等 10个位点进行基因型检测并应用于法医物证学个体识别案件。方法 :用PCR复合扩增结合四色荧光检测技术对样本DNA进行基因分型。结果 :常见物证检材可成功地得到检验。结论 :这些位点适用于法医物证学个体识别。     

D8S384基因座的遗传多态性及其在法医物证检验中的应用

揭示人类自然群体中D8S384基因座的基因型频率,评估D8S384基因座在法医物证中的应用价值,以及建立D8S384基因座的分型方法。用不同基因型PCR产物混合的方法,制备了D8S384等位基因分型标准物,并按照国际法医血液遗传学会DNA委员会推荐的原则命名了等位基因。采用PCR扩增、电泳分析、银染显色的方法,调查了世界3大人种11个群体1103名个体的D8S384基因型。D8S384基因座共有8个等位基因,群体内基因型分布符合Hardy－Weinberg平衡,群体间基因型构成有显著性差异。利用群体数据估计了D8S384基因座的法医学理论应用价值,计算得出D8S384基因座的期望杂合度为0．704±0．014,个人识别机率为0．864。D8S384基因座是一个较好的法医学STR遗传标记。     

降解检材STR分型Ladder-Like条带形成原因的探讨

目的探讨降解DNA短串联重复序列PCR扩增产物在PAGE中Ladder-L ike条带的形成原因。方法用一组人工合成的不同长度的D8S1179DNA单链,模拟降解检材中的断裂DNA;利用John M设计的D8S1179引物对模拟模板的DNA单链进行PCR扩增,PAGE分离。结果不同模拟模板的DNA单链的组合可以扩增出不同的Lad-der-L ike条带。结论短串联重复序列Ladder-like条带是PCR过程中降解DNA多态区互补扩增的产物。     

山西地区汉族人群4个STR基因座的遗传多态性

<正> 为建立不同民族和地区DNA分型数据库的需要,以便于法医在检案中对不同民族和地区之间的差异进行相关分析,本文作者对山西地区173名汉族无关个体进行了D5S818、D18S51、D3S1358、D21S11等4个基因座的群体遗传学调查,现报道如下。     

国外论文文摘

根据模拟的法医样品作DNA中D1S80的分型[刊,英]/Baechtel,F.S.;Presley,K.W.//法庭科学杂志.-1995,40(4),-536-545 DIS80分型程序的可靠性用模拟的法医样品进行了评价。取自曝露于阳光下达20周的血斑中的DNA内的D1S80等位基因是可测定的。然而,曝露于阳光下6周后的精斑中的D1S80等位基因无法测定。对保存于各种基质的血和精液的分析以及20多周内的反复检验揭示,基质地确定D1S80型的能力没有分类上的影响。一项将体液放置于诸如漂白剂、酸、石油和汽油等普通化学物质的研究表明,仅有HCI和漂白剂对D1S80型的分型能力有不利影响。另外,令人关注的化学产品     

阴茎拭子在1例强奸案件中的应用

1案件简介李某(女)报案称:于某日凌晨2时许酒后休息时朦胧中被左某强奸,但左某拒不承认。法医提取受害人李某血样及阴道擦拭物、提取左某的阴茎(龟头)拭子及血样进行DNA检验。执行标准GA/T383-2002标准方法,阴棉、卫生纸上未检出精子。用Chelex法分别提取阴茎拭子上细胞DNA及受害人李某、嫌疑人左某血液DNA。用Promega-powePlex16系统,经PCR方法符合扩增多个STR基因座,用ABI-3100序列分析仪进行基因分析,得到基因分型(见表1)。表1 DNA分型结果D3S1358 TH01 D21S51 D18S51李某15/17 9 29/30 14/19阴茎拭子15/17 9 29/30 14/19…     

15个常染色体和18个Y染色体STR基因座复合扩增检测体系及法医学应用

目的建立15个常染色体和18个Y染色体STR基因座以及性别基因座的六色荧光标记复合PCR直扩检测体系,并评估其法医学应用价值。方法采用六色荧光标记技术,建立15个常染色体STR基因座(D3S1358、D13S317、D7S820、D16S539、TPOX、TH01、D2S1338、CSF1PO、D19S433、v WA、D21S11、D18S51、D8S1179、D5S818、FGA)和18个Y染色体STR基因座(DYS527a/b、DYS448、DYS456、DYS385a/b、DYS458、DYS391、DYS390、DYS19、DYS438、DYS393、DYS389Ⅰ、DYS439、DYS389Ⅱ、DYS392、GATA、DYS635)以及Amelogenin的复合扩增体系,收集800份无关人员血样进行基因座检测,评估所建复合扩增体系的稳定性、灵敏度、种属特异性、直扩可行性以及抗抑制性。结果本检测体系对800份无关人员血样复合扩增后,结果准确,灵敏度达0.125ng;种属特异性高;38份案件检材全部准确分型。在对照男性与女性的DNA浓度比值大于等于1:4时,男性DNA的所有基因座均能准确分型。若模板DNA中含一定浓度的已知抑制剂时,所有基因座也均准确分型。结论本文建立的复合扩增检测体系可同时检测15个常染色体和18个Y染色体基因座以及性别基因座,结果稳定准确,灵敏度高,可为法医DNA检测分析提供一个新选择。     

Detection of cellular material within handprints

A novel technique for the visualisation of cellular material has been published harnessing an external binding nucleic acid fluorescence dye, Diamond™ dye (DD), in combination with a digital fluorescence microscope. This technique can effectively detect cellular material on an object transferred by touch allowing targeted collection of latent DNA. Previous studies on the visualisation of touch DNA have focussed on transfer from fingertips only.Here we report on the visualisation of cellular material transferred via twenty different positions over the entire handprint. Three volunteers (a heavy, an intermediate and a light shedder) were asked to press their hands onto a plastic surface with medium pressure for 15 s at undefined time points post-handwashing, creating a complete handprint. DD was applied to the entire area and the presence of cellular material was recorded based on cells within 5 separate frames at each of the 20 positions. All tests were performed in triplicate such that the final dataset contained 1,800 observed frames.This extensive study allows accurate monitoring of cellular transfer deposited by different parts of the hand. Our study highlights which areas of an individual’s hand shed the greatest, or least, amount of cellular material. This simple process can act as a guide for DNA collection from items held within the entire hand, rather than only touched by the fingertips only, such as weapons, knives and steering wheels.     

Gunshot residue patterns on skin in angled contact and near contact gunshot wounds

The goal of this study was the reproduction of shape and pattern of gunshot residues in near contact and contact gunshot wounds by a series of experimental gunshots on a skin and soft tissue model. The aim was to investigate the shape and direction of soot deposits with regard to the muzzle according to different muzzle-target angles, firing distances, type of ammunition and weapon and barrel length. Based on a review of the literature and on the results of the experiments the authors could make the following statements of gunshot residues in angled contact and close contact gunshot: (1) gunshot residues on the target surface can be differentiated in a "inner" and "outer powder soot zone"; (2) the outer powder soot zone is much less visible than the inner powder soot zone and may lack on human skin; (3) with increasing muzzle target distance both inner and outer powder soot halo increase in size and decrease in density; (4) in angled shots the inner powder soot halo shows an eccentric, elliptic shape which points towards the muzzle, regardless of ammunition, calibre and barrel length; (5) the outer powder soot points away from the muzzle in angled contact and close contact shots.     

Transfer of DNA without contact from used clothing,pillowcases and towels by shaking agitation

DNA is frequently retrieved from commonly used objects or surfaces with no apparent biological stains. This DNA may have come from one or more individuals who directly deposited their DNA, or indirectly transferred the DNA of others, when physically contacting the sampled object or surface. Furthermore, contactless indirect DNA transfer of this ‘touch DNA’ from fabric substrates was recently demonstrated to be possible in a controlled laboratory environment. The circumstances and extent to which this form of contactless DNA transfer occurs are largely unknown. This study investigated indirect DNA transfer without contact by applying a gentle shaking agitation to used clothing, pillowcases and towels, with known usage and history, of 10 volunteers above the collection zone of the secondary surface. DNA transfer frequently occurred and was possible from all three investigated items. It occurred at levels that often produced informative profiles where transferred profiles closely resembled the profiles generated from the primary item. The outcomes of this study contribute to expanding the understanding of indirect DNA transfer without contact. However, this field would benefit from investigating a wider range of agitations and/or item types with various histories of use to determine the level of transfer and its detectability under different conditions.     

Determination of DNA yield rates in six different skeletal elements in ancient bones

Current sampling strategy for laboratories typing bones for human identification include samples obtained from femur, tooth and temporal bone. Latest studies suggest that the small bones of the hands and feet were very similar or even better in DNA yield. These bones can be easily sampled with a disposable scalpel and thus reduce potential DNA contamination. The aim of our study was to determine the suitability of metatarsals, metacarpals and phalanges for genetic identification. 48 bone samples from 8 different skeletons (six from 18^th century and two from 3rd century) were obtained from 5 archaeological sites in Slovenia. In each skeleton, 6 different skeletal elements were sampled (temporal bone, molar, femur, metacarpal bone, metatarsal bone and proximal phalanx of the hand), and strict precautions followed to prevent contamination. Half of gram of bone powder was decalcified using full demineralization extraction method. The DNA was purified in a Biorobot EZ1 (Qiagen), DNA content determined with the PowerQuant kit (Promega), and autosomal STR typing performed with the Investigator ESSplex Plus kit (Qiagen). Up to 8.75 ng DNA/g of powder was obtained from samples analyzed. The highest yields were detected in temporal bone and the lowest in femur. The success rate of STR typing was evaluated according to the number of successfully typed loci and a strong correlation between the success rate of STR typing and the amount of extracted DNA was confirmed. For all eight skeletons full consensus genetic profiles were determined from skeletal elements analyzed. Our findings suggest it would be suitable to include metatarsal and metacarpal bones in sampling strategy for human identification although further research is needed to substantiate the findings of this study.     

The effect of various stain carriers on the quality and quantity of DNA extracted from dried bloodstains

Bloodstains were made with 200 microliters blood on each of 11 different common substrates to examine the effect of the stain carrier on the amount and quality of DNA recoverable. High-molecular-weight DNA was extracted from all samples after 2 days. The yield of DNA from each sample varied considerably, not only between the different stain carriers but also within a given category. With a DNA yield of up to 10 micrograms, paper, glass, nylon, wood, smooth leather and wool gave the best results, followed by blue denim and wallpaper (up to 6 micrograms), cotton fabric and carpeting (up to 4 micrograms) and suede (up to 2 micrograms). For several stain carriers the DNA-containing solution was contaminated by chemical substances, which in the case of the blue denim, suede, and carpet samples inhibited the digestion of the DNA with restriction enzymes and prevented DNA typing. The different textures of the stain carriers tested and (as for varying yields on the same carrier) the differing degree of loss of DNA during extraction and the physiological variation in the number of leukocytes in human blood are discussed as possible reasons for the wide range of variation in the amounts of DNA it was possible to extract.     

1对同卵双生新生儿DNA甲基化谱差异分析

目的 探索1对同卵双生新生儿之间DNA甲基化谱的差异.方法 应用甲基化免疫共沉淀结合高通量测序法对1对同卵双生新生儿的DNA甲基化谱进行检测,分析基因组DNA甲基化特点及其之间的差异,筛选适用于法医学分析的甲基化位点.结果 两样本各获得7300万原始测序序列(raw reads)数据,与人类基因组参考序列比对,各得到4800万和5000万唯一比对reads,其中大部分分布在重复区域,且在Alu序列分布最为广泛.两样本DNA甲基化富集区域(peak)各检测到257 362条和197 272条,基因组覆盖率分别为6.53％和5.29％,分布在基因组不同区域,以中间内含子区含量最多.分析两样本甲基化差异区域得到2205条差异的甲基化序列,其中595条位于基因区域,1610条位于基因间区,从中筛选出113条序列,用于进一步深入研究其法医学应用价值.结论 本研究初步证实了DNA甲基化用于同卵双生子鉴定的可行性,为筛选同卵双生子DNA甲基化差异位点提供了基础数据.     

The characteristics of the formation of head wounds from the action of solid blunt objects

The results of wound investigation based on blow theory are presented and regularities concerning wound formation are defined. Zones were singled out in each lesion, which differed by formation mechanism and time of occurrence (zone of primary contact, zone of secondary contact and non--contact lesions--lacerations). Formation of primary contact zone doesn't depend on blow strength, its increase is accompanied by lesion extension. Fundamental differences in wound formation in case of blow by objects with verge as striking surface are presented.     

Evaluation of Skin Surface as an Alternative Source of Reference DNA Samples: A Pilot Study

An acceptable area for collecting DNA reference sample is a part of the forensic DNA analysis development. The aim of this study was to evaluate skin surface cells (SSC) as an alternate source of reference DNA sample. From each volunteer (n = 10), six samples from skin surface areas (forearm and fingertips) and two traditional samples (blood and buccal cells) were collected. Genomic DNA was extracted and quantified then genotyped using standard techniques. The highest DNA concentration of SSC samples was collected using the tape/forearm method of collection (2.1 ng/μL). Cotton swabs moistened with ethanol yielded higher quantities of DNA than swabs moistened with salicylic acid, and it gave the highest percentage of full STR profiles (97%). This study supports the use of SSC as a noninvasive sampling technique and as a extremely useful source of DNA reference samples among certain cultures where the use of buccal swabs can be considered socially unacceptable.     

Recovery of DNA from bone without demineralization

This study assessed the performance of five different DNA extraction methods for the recovery of DNA from bone: ChargeSwitch® gDNA Plant Kit, DNA IQ™ System Kit, DNeasy® Blood & Tissue Kit, PrepFiler® BTA Forensic DNA Extraction Kit and phenol-chloroform-isoamyl alcohol. DNA was extracted from pig rib and femur bones that was fresh, had undergone surface decomposition for three months, and had undergone surface decomposition for one year. Extracted DNA was analyzed using real-time PCR and amplification of an in-house PCR multiplex that assessed the quality and quantity of DNA and for the presence of inhibitors. The phenol-chloroform-based method consistently yielded the highest amounts of DNA and DNA IQ the lowest; however, all methods produced relatively high yields of DNA from both pig rib and femur samples that could be amplified without any detected inhibition. The data demonstrate that with reasonable quality bone samples any of the tested methods can isolate DNA that can be successfully analyzed. The effective use of internal PCR controls is also demonstrated.     

An already archived latent fingerprint as a DNA source for STR typing in a murder case

Former studies have shown that even a single skin contact, resulting in a latent fingerprint, can transfer enough DNA for genetic analysis. However, up to now latent fingerprints have usually not been used for DNA typing. In the present case the smeared trace of a hand was found in the suspect's car and archived. As it could not be evaluated in a classical manner, the evidence had to be examined by molecular genetic methods. DNA was extracted and typed in five different STR loci. Based on the yielded results, the significance of the findings is discussed.