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1.
Two different insertion/deletion (indel) multiplexes have been used to analyse a subset of the CEPH Human Genome Diversity Panel as well as several additional populations collected locally in order to compare the effectiveness of the marker sets in differentiating the populations on a continental level. We show that both marker sets by themselves are able to achieve full continental population differentiation and combining all 67 markers leads to considerably higher accuracy of classification. While differentiation of the European and Middle Eastern population groups remains impossible, surprisingly high accuracy is achieved in assigning Central South Asian samples.  相似文献   

2.
For the analysis of degraded DNA in disaster victim identification (DVI) and criminal investigations, single nucleotide polymorphisms (SNPs) have been recognized as promising markers mainly because they can be analyzed in short sized amplicons. Most SNPs are bi-allelic and are thereby ineffective to detect mixtures, which may lead to incorrect genotyping. We developed an algorithm to find non-binary (i.e. tri-allelic or tetra-allelic) SNPs in the NCBI dbSNP database. We selected 31 potential tri-allelic SNPs with a minor allele frequency of at least 10%. The tri-allelic nature was confirmed for 15 SNPs residing on 14 different chromosomes. Multiplex SNaPshot™ assays were developed, and the allele frequencies of 16 SNPs were determined among 153 Dutch and 111 Netherlands Antilles reference samples. Using these multiplex SNP assays, the presence of a mixture of two DNA samples in a ratio up to 1:8 could be recognized reliably. Furthermore, we compared the genotyping efficiency of the tri-allelic SNP markers and short tandem repeat (STR) markers by analyzing artificially degraded DNA and DNA from 30 approximately 500-year-old bone and molar samples. In both types of degraded DNA samples, the larger sized STR amplicons failed to amplify whereas the tri-allelic SNP markers still provided valuable information. In conclusion, tri-allelic SNP markers are suited for the analysis of degraded DNA and enable the detection of a second DNA source in a sample.  相似文献   

3.
Tests that infer the ancestral origin of a DNA sample have considerable potential in the development of forensic tools that can help to guide crime investigation. We have developed a single-tube 34-plex SNP assay for the assignment of ancestral origin by choosing ancestry-informative markers (AIMs) exhibiting highly contrasting allele frequency distributions between the three major population-groups. To predict ancestral origin from the profiles obtained, a classification algorithm was developed based on maximum likelihood. Sampling of two populations each from African, European and East Asian groups provided training sets for the algorithm and this was tested using the CEPH Human Genome Diversity Panel. We detected negligible theoretical and practical error for assignments to one of the three groups analyzed with consistently high classification probabilities, even when using reduced subsets of SNPs. This study shows that by choosing SNPs exhibiting marked allele frequency differences between population-groups a practical forensic test for assigning the most likely ancestry can be achieved from a single multiplexed assay.  相似文献   

4.
In some forensic cases, nuclear DNA is degraded and cannot be analyzed. In such a case mitochondrial DNA (mtDNA) is usually used in forensic cases for identification because of its special features as high number of copies per cell, maternal inheritance and high mutation rate. Single nucleotide polymorphisms (SNPs) represent the most abundant class of human polymorphisms. The aim of this study was optimization of 10 mtDNA SNPs by using SNaPshot minisequencing technique on ABI310 genetic analyser in forensic molecular genetics laboratory. At the end of this study, the optimization of minisequencing technique was done by changing some assay parameters. Also, during the optimization of 10 mtSNP loci in our laboratory.  相似文献   

5.
Allele frequencies for 16 previously described autosomal SNPs were tested in 1020 unrelated individuals originating from three different continents (Africa, Asia and Europe). The populations analyzed included Africans from Benin Gulf (180), Asians from Mongolia (160) and Europeans from Italy (680).  相似文献   

6.
Applying two extraction protocols to isolate DNA from a charred femur recovered after a major forest fire, a range of established and recently developed forensic marker sets that included mini-STRs and SNPs were used to type the sample and confirm identity by comparison to a claimed daughter of the deceased. Identification of the remains suggested that the individual had been dead for 10 years and the DNA was therefore likely to be severely degraded from the combined effects of decomposition and exposure to very high temperatures. We used new marker sets specifically developed to analyze degraded DNA comprising both reduced-length amplicon STR sets and autosomal SNP multiplexes, giving an opportunity to assess the ability of each approach to successfully type highly degraded material from a challenging case. The results also suggest a modified ancient DNA extraction procedure offers improved typing success from degraded skeletal material.  相似文献   

7.
Allele frequencies of 30 InDel markers previously selected and validated for forensic purpose were assessed in 419 unrelated individuals originating from five different populations of Chinese Han, Chinese Hui, Uighur, Mongolian and Tibetan in P.R. China. Hardy–Weinberg equilibrium tests and linkage disequilibrium analysis were performed and the results showed that allele frequency distributions of the 30 InDel markers had meet the genetic equilibrium in all of the five populations and the InDel markers on same chromosome did not generate any linkage block. Analysis of molecular variance (AMOVA) indicated that genetic variation among the 5 studied populations represent only 4.00% of the total genetic diversity. We observed the cumulative power of discrimination (CPD) for each studied population was 0.99999999999841 in Chinese Han population, 0.99999999999690 in Chinese Hui population, 0.99999999999709 in Uighur population, 0.99999999999772 in Mongolian population and 0.99999999999854 in Tibetan population.  相似文献   

8.
用熔解曲线法分析插入/缺失多态性和Y染色体SNPs多态性   总被引:3,自引:0,他引:3  
随着单核苷酸多态性SNPs (SingleNucleotidePolymorphisms)及插入 /缺失多态性Indels (Insertion/Dele tion)的分型技术研究的深入 ,SNPs和Indels在法医学上的应用将受到深刻的影响。本文研究和探讨Indels的分型方法 ,通过测定扩增DNA片段在溶液中的溶解曲线图确定每个样品的基因型 ,称为溶解曲线Indels基因分型方法(McI/D)。溶解曲线图由被测样品DNA片段的特殊溶解温度组成 ,扩增结果直接由仪器分析不需要繁杂的PCR后期操作。  相似文献   

9.
目的建立一种既节省模板、又能延长测序长度的m tDNA单倍型(群)分析方法,构建中国蒙古族mtDNA单倍型类型关系树。方法用复合扩增、巢式PCR对201名中国蒙古族m tDNA样本进行D-环区、3010~3460、4640~5204、10171~10659和14478~15204编码区域的测序分析,部份样品进行L3953/H4508等区域的测序;根据其多态界定各样本单倍型并进行聚类分析。结果L15996/H107等巢式PCR扩增产物经测序检验结果互不干扰,其分型以A等东亚人群常见的单倍型(群)为主,包括部份HV、K、J、I和U等欧洲人群优势单倍型(群),23个单倍群和共53个单倍型全部归为欧亚人群特有的M和N两大类单倍类群并呈巢式聚类。结论本研究选取的测序区域适用于构建我国各民群的m tDNA单倍型(群);复合扩增、巢式PCR法既节省模板DNA,又延长测序的长度,适用于法医学、考古学研究中的微量样本的检测。  相似文献   

10.
Preliminary tests for the detection of stains at crime scenes aim to focus the police work making them more efficient in the combat of criminality. The application of the luminol chemiluminescence reaction (3-aminoftalhidrazida) in presumptive tests for the detection of bloodstains is known for more than 40 years in forensic science. This reaction is based on the emission of light through the chemical reaction of luminol mixed with hydrogen peroxide and a hydroxide in the presence of a catalytic molecule (iron from the hemoglobin) (Laux [1]).This work evaluates the luminol interference and its effect on subsequent serological and DNA testing. Samples prepared with blood and different concentrations of luminol solution containing luminol, peroxide of hydrogen and sodium carbonate, were analyzed. Additionally, samples of serial dilutions of standard DNA mixed with luminol solution were also analyzed. Although presumptive tests with luminol do not establish the characterization and identification of stains at crime scenes, preliminary results indicated that it is suitable for the detection of invisible bloodstains for forensic analysis, with few detrimental effects on the serological tests and subsequent DNA recovery and typing.  相似文献   

11.
In this study, a sample of 225 Guatemalan males, comprising 115 Mestizo-Guatemalan and 110 Mayan-Guatemalan, was typed for 17 Y-short tandem repeats (STRs) loci (DYS19, DYS389I, DYS389II, DYS390, DYS391, DYS392, DYS393, DYS437, DYS438, DYS439, DYS448, DYS456, DYS458, DYS635, YGATA_H4.1 and DYS385a/b). The haplotype diversity (H = 1) and discrimination capacity (96.86%) were calculated. Analysis of molecular variance (AMOVA) demonstrated a low but significant interpopulation differentiation when compared with the results obtained when we confront the Mestizo and Mayan populations with the European populations.Furthermore, the genetic variability and differences among the American, African, Asian, and European populations were analyzed with the software Statistica 9.1. In addition, the genetic distances were also calculated using other published data. Reynolds and Slatkińs genetic distance was visualized using the multidimensional scaling (MDS) analysis. All the analysis performed locates the Mayan population next to the Native American population, while Guatemalan-Mestizo population was found to be between these populations and the European population, similar to other Mestizo one.The implementation of the estimation of individual ancestry proportions of the whole population sample showed the presence of two well-differentiated population groups.  相似文献   

12.
线粒体16srRNA和ND4基因在种属鉴定中的应用研究   总被引:1,自引:1,他引:1  
目的构建一种用于种属鉴定的线粒体DNA(m tDNA)16 srRNA和ND4基因荧光标记复合扩增检测体系。方法利用引物设计软件(Prim er 5)对两个m tDNA序列ND4基因和16 srRNA基因设计两对引物,每对引物中的一条在5’端标记荧光素(6-FAM)。按传统复合扩增技术建立复合扩增体系,用AB I PR ISM 310基因分析仪对产物进行分析。结果人类DNA扩增产物出现两个峰,片段大小分别为110bp的人类特异片段和149bp的人与动物共有片段,而动物DNA扩增产物出现一个峰,片段大小为149bp。对30个实验室存放5~15年的陈旧人血痕也能明确判断其种属来源。结论该体系可以明确区分人源性生物检材与其它常见动物样本,对实验室长期存放的陈旧检材也具有较好的检测能力。  相似文献   

13.
Y-STR markers are a valuable tool in the analysis of biological traces in which a mixture of male and female trace material is to be expected. It is possible to generate a Y-chromosome DNA profile, even if all the prior sperm tests are negative and no sign of any male component is found in amelogenin. In 38 of a total of 239 sexual offences a perpetrator trace was identified solely using Y-STR analysis. Based on these findings, the Austrian National DNA Database was expanded to include Y-STRs in 2012 with the primary objective to identify serial sexual offences.  相似文献   

14.
目的研究人脾脏细胞DNA含量改变与死亡时间的关系。方法选取36例已知死亡时间的人体脾脏,在死后5~36h内逐时进行细胞学涂片、Feulgen Vans染色观察,并用图像分析系统,测定脾脏细胞核积分光密度、平均灰度等灰度参数,所得数据用SPSS软件分析。结果在5~36h内平均光密度、积分光密度、平均灰度均值均与死亡时间显著性相关,并得出对应的回归方程,其中平均光密度、积分光密度随死亡时间的延长而逐渐减小、平均灰度逐渐增大。结论人脾脏细胞核DNA含量改变呈现一定规律,与死亡时间明显相关。  相似文献   

15.
目的建立了新型微流体液相色谱(micro-LC)串联四级杆质谱检测头发中5种苯二氮卓类药物(三唑仑,α-羟基咪达唑仑,咪达唑仑,α-羟基阿普唑仑,普拉西泮)。方法采用液-液萃取法(LLE)提取毛发样品,微流体液相色谱串联四级杆质谱检测。结果在回归系数大于0.99的情况下,目标分析物的良好线性。精密度和萃取效率分别在2.7%~17.1%和66.5%~120.5%之间。每个分析物的检出限和定量限分别为0.001~0.08 pg·mg^-1和0.0125~0.25pg·mg^-1。结论本方法与传统的液相色谱串联质谱法(LC/MS-MS)相比灵敏度出高2-10倍。本研究展示了新型微流体分离系统串联质谱方法的实用性,并为法医毒理学领域关于头发样本中痕量药物检测提供了一种新的检测手段。  相似文献   

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目的探讨利用母体血浆中高甲基化RASSF1A位点进行胎儿SNP分型的应用价值。方法随机收集10个未孕健康妇女和45例不同孕期(早期5例、中期20例、晚期20例)孕妇的血样本及相应胎儿组织(绒毛组织、羊水、胎盘组织);利用甲基化敏感限制性内切酶BstUI酶切后进行PCR,产物进行血细胞、血浆和胎儿组织(绒毛或胎盘)DNA RASSF1A序列的甲基化模式检测,并采用直接测序法对SNP rs4688725位点进行分型。结果经BstUI酶消化,RASSF1A序列在母体血细胞中均未检出,而在绒毛或胎盘组织中均能检出;在45名孕妇血浆中,RASSF1A序列均能被检出,且序列内的SNP分型与相应胎儿组织一致;在10名非孕妇女血浆中均未检出RASSF1A序列。结论母体和胎儿DNA中RASSF1A基因启动子区域的甲基化模式存在差异,可用于对母体血浆中的游离胎儿DNA进行SNP分型。  相似文献   

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