Detection of genotype recycling fraud in U.S. immigrants

Abstract: Relationship testing laboratories provide genetic evidence to support or refute claims of kinship between U.S. citizen petitioners and potential immigrant beneficiaries. One female beneficiary presented a male amelogenin type and alleles at 15 autosomal loci that were identical to an alleged brother’s. Laboratory records showed that her alleged father had petitioned to have 15 children emigrate from Ghana. The petitioner’s 15 paternity indices exceeded 10⁵, but the children shared only four short tandem repeat (STR) profiles, suggesting fraudulent reuse of genotypes in this alleged pedigree (AP). To determine the extent of this “genotype recycling,” I examined the laboratory’s 555 APs from Ghana and 532 control APs from Nigeria. Seventeen Ghanaian APs (3.1%) but no Nigerian APs showed genotype recycling. Of 90 tested people in the 17 APs, 56 shared identical STR profiles with others in their AP. Of these 56 people, 10 were petitioners with unexpectedly high parentage indices. Seven of 56 had amelogenin types that disagreed with their declared genders. Database searches for identical multilocus genotypes in allegedly different people would best detect this fraud.     

贵州地区汉族Penta D和Penta E基因座遗传多态性

有关Penta D和PentaE基因座遗传多态性调查,国内外文献已有多篇,但尚无对我国贵州地区的遗传学数据报道,为此本文进行了调查,现报道如下。     

广西壮、汉族人群F13A01、FESTPS、vWA三个STR基因座的遗传多态性

采用复合扩增、PAG电泳分离和银染检测技术,对广西壮、汉族人群的F13A01、FESFPS、vWA等3个STR基因座进行遗传多态性研究.3个基因座的基因型在广西壮、汉族人群的频率分布均符合Hardy-wein-berg平衡.3个STR基因座在广西壮族人群的个体识别力(DP)分别为0.8205、0.8566和0.9239;在广西汉族人群的个体识别力(DP)分别为0.8256、0.8455、0.9191.     

Validation of Half‐Reaction Amplification Using Promega PowerPlex® 16*

Abstract: DNA amplification is a fundamental yet costly process used in DNA analysis. This study evaluated half‐reaction amplification (12.5, 12, and 13 uL) using the Promega Powerplex^® 16 Kit with the hope of reducing sample analysis costs by half. A sensitivity study was completed, along with the testing of various blood stain samples including those with low (<0.40 ng) and high DNA concentrations (>3.0 ng), peak height imbalances, and allelic drop‐out. Also, 467 samples submitted to the MUFSC laboratory for testing were analyzed. Results indicate that half‐reaction amplification produced higher quality profiles than full‐reactions. Average peak heights increased by 85%, peak height imbalances improved, and drop‐out was eliminated in 75.8% of samples. Only eight of 467 case samples required re‐amplification, a success rate of 94% was observed, and the repeat rate decreased significantly. Finally, a DNA input of 0.25–1.0 ng is ideal for half‐reaction amplification.     

Allele frequency distribution based on 17 STR markers in three major Dravidian linguistic populations of Andhra Pradesh, India

Allele frequencies for 15 tetranucleotides and 2 pentanucleotides repeat loci were determined in 317 unrelated, healthy individuals of Andhra Pradesh, India, belonging to three pre-dominant endogamous populations namely, Kappu Naidu, Kamma Chaudhary and Kapu Reddy. Adherence to the expectations of the Hardy-Weinberg equilibrium (HWE) was confirmed for all loci with few exceptions, which were not significant after applying Bonferroni's correction. Statistical parameters of forensic interest; observed heterozygosity, probability of homozygosity, probability of extact test, power of discrimination, match probability, polymorphism information content, power of exclusion and mean paternity index were determined for all loci. The present study reveals that Penta E and D2S1338 are the most informative loci in all the studied populations. The combined power of discrimination was greater than 0.976, whereas the cumulative power of exclusion gave an expected value of 0.9999 for all the tested microsatellite loci. No difference was observed in the discriminatory power of 15 loci in studied populations on comparison with other populations of India. Population differentiation tests revealed significant differences between the studied and neighboring populations at several loci. Analyzed parameters indicate the utility and efficacy of the studied 17 STR systems as a powerful tool in forensic human identification, paternity testing and human population genetic studies.     

江西汉族人群D2S1338、TPOX、TH01基因座多态性

本文采用Amp-FLP技术和银染法对D2S1338、TPOX、TH013个STR基因座遗传多态性进行了调查,现报道如下。1材料与方法1.1样本的采集及处理随机采集220人份江西地区汉族人群无血缘关系的个体静脉全血1m l,ACD抗凝。1.2 PCR扩增及产物的检测采用多位点STR同步扩增法,采用聚丙烯酰胺凝胶DNA电泳和银染法[1]。1.3统计学处理用χ2检验判断各位点的基因型分布是否符合Hardy-W einberg平衡法则,计算期望杂合度(H)、个体识别率(DP)和多态性信息含量(PIC值)[2]。2结果D2S1338共检出等位基因12个,基因频率分布在0.0023~0.1758之间;TPOX共…     

Developmental validation of reduced-size STR Miniplex primer sets

This paper describes a developmental validation study of three Miniplex sets covering 12 of the 13 CODIS loci. As these new sets will be used for the analysis of degraded and low level DNA, the validation studies were performed using 100-125 pg of DNA, the lowest input level at which peak balance, peak intensity, and allele consistency were stable. To demonstrate the applicability of the Miniplex sets to forensic casework, these validation studies were completed in accordance with the Scientific Working Group on DNA Analysis Methods (SWGDAM). A range of tests were performed including studies of concordance with standard multiplex kits, sensitivity and reproducibility, and PCR amplification conditions. Additionally, studies of mixtures, nonhuman and environmentally degraded DNA, and simulated forensic samples were performed. Our results demonstrate that Miniplex STR amplification procedures are a robust and sensitive tool for the analysis of degraded DNA.     

Developmental validation of the AmpFℓSTR® Identifiler® Plus PCR Amplification Kit: an established multiplex assay with improved performance

Abstract: Analysis of length polymorphism at short tandem repeat (STR) loci utilizing multiplex polymerase chain reaction (PCR) remains the primary method for genotyping forensic samples. The AmpF?STR^® Identifiler^® Plus PCR Amplification Kit is an improved version of the AmpF?STR^® Identifiler^® PCR Amplification Kit and amplifies the core CODIS loci: D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, CSF1PO, FGA, TH01, TPOX, and vWA. Additional loci amplified in the multiplex reaction are the sex‐determinant, amelogenin, and two internationally accepted loci, D2S1338 and D19S433. While the primer sequences and dye configurations were unchanged, the AmpF?STR^® Identifiler^® Plus PCR Amplification Kit features an enhanced buffer formulation and an optimized PCR cycling protocol that increases sensitivity, provides better tolerance to PCR inhibitors, and improves performance on mixture samples. The AmpF?STR^® Identifiler^® Plus PCR Amplification Kit has been validated according to the FBI/National Standards and Scientific Working Group on DNA Analysis Methods (SWGDAM) guidelines. The validation results support the use of the AmpF?STR^® Identifiler^® Plus PCR Amplification Kit for human identity and parentage testing.     

Genetics and genomics of core short tandem repeat loci used in human identity testing

Over the past decade, the human identity testing community has settled on a set of core short tandem repeat (STR) loci that are widely used for DNA typing applications. A variety of commercial kits enable robust amplification of these core STR loci. A brief history is presented regarding the selection of core autosomal and Y-chromosomal STR markers. The physical location of each STR locus in the human genome is delineated and allele ranges and variants observed in human populations are summarized as are mutation rates observed from parentage testing. Internet resources for additional information on core STR loci are reviewed. Additional topics are also discussed, including potential linkage of STR loci to genetic disease-causing genes, probabilistic predictions of sample ethnicity, and desirable characteristics for additional STR loci that may be added in the future to the current core loci. These core STR loci, which form the basis for DNA databases worldwide, will continue to play an important role in forensic science for many years to come.     

Triton X-100快速提取甲醛固定、石蜡包埋组织内DNA的方法

目的建立一种快速提取甲醛固定、石蜡包埋组织内DNA的方法。方法利用TritonX-100一步提取甲醛固定、石蜡包埋组织内DNA,并具体研究了不同浓度TritonX-100对提取后DNA-STR分型效果的影响。结果成功地一步提取出甲醛固定、石蜡包埋组织内DNA,浓度为1%的TritonX-100提取效果较好。结论利用TritonX-100提取甲醛固定、石蜡包埋组织内的DNA,为快速提取DNA提供了有效的途径,是法科学领域中一种值得推荐的方法。     

Development and validation of the AmpFℓSTR® Identifiler® Direct PCR Amplification Kit: a multiplex assay for the direct amplification of single-source samples

Abstract: The AmpF?STR^® Identifiler^® Direct PCR Amplification Kit is a new short tandem repeat multiplex assay optimized to allow the direct amplification of single‐source blood and buccal samples on FTA^® card without the need for sample purification and quantification. This multiplex assay has been validated according to the FBI/National Standards and SWGDAM guidelines. Validation results revealed that slight variations in primer concentration, master mix component concentration, and thermal cycling parameters did not affect the performance of the chemistry. The assay’s sensitivity was demonstrated by amplifying known amounts of white blood cells spotted onto FTA^® cards, and the assay’s specificity was verified by establishing minimal cross‐reactivity with nonhuman DNA. No effect on the age of the sample stored on the FTA^® substrate was observed and full concordance was established in the population study. These findings of the validation study support the use of the Identifiler^® Direct Kit for forensic standards and database samples genotyping.