Evaluation of reliability of STR typing in human colon carcinomas tissues used for identification purpose

The short tandem repeats (STRs) have become an important and widely used tool in forensic casework. Clinical tissue samples are not usually employed in forensic casework, but sometimes, malignant tissue samples may be the only source of biological material for forensic investigations. However, in use of such samples, uncertainties due to microsatellite instability (MSI) and loss of heterozygosity (LOH) may be encountered. In our study of 77 human colon carcinomas tissue with the AmpFlSTR Identifiler Kit comprising 15 STR loci and the amelogenin gene, we detected four kinds of changes between normal tissue and tumor tissue including pLOH, LOH, occurrence of an additional allele (Add) and occurrence of a new allele (New) instead of that found in normal tissue. The overall variation detectable rate was 11.28%, of which pLOH was 79.1%, LOH was 7.9%, Add was 7.9% and New was 5%. Of the above four changes, the incidence rate of pLOH, LOH, Add and New was respectively 8.93%, 0.89%, 0.89% and 0.57%. The STRs mostly affected were D18S51, D5S818, FGA and D19S433. Only pLOH was found at five loci including vWA, TPOX, TH01, D13S317 and amelogenin gene. Our results demonstrate that great care should be taken in the evaluation of typing results obtained from clinical tissue specimens, in particular when no reference samples are available, because genetic instability is a very common event observed in different tumors and the STRs used for individual identification could sometimes be affected.     

Loss of heterozygosity detected in a short tandem repeat (STR) locus commonly used for human DNA identification

Short tandem repeat (STR) markers are commonly used in basic genetic research and in human identification testing. Clinically, STRs can be used to study genetic alterations in tumors. A genetic deletion common to many types of cancer is referred to as the loss of heterozygosity (LOH). Numerous examples of LOH in cancer have been described and some have been mapped to areas located in close proximity to markers employed in human identity testing. Despite this fact, LOH has rarely been observed for STR loci commonly employed in forensic testing. Recently, for medico-legal purposes, we were asked to determine whether a tissue biopsy originated from a particular individual. For a reference source we assessed two specimens, one from normal tissue and one from cancerous tissue. When both reference specimens were used to generate DNA profiles, we observed LOH at one STR locus, D13S317. As demonstrated in other cancers only the cancerous biopsy demonstrated LOH. The forensic community should be cognizant of these unusual circumstances because, as identification of human DNA continues to be used more extensively, certain instances will arise in which reference material will not be readily available. In these situations, archived specimens may be employed as a reference source. Clinical specimens such as tissue biopsies should be used with caution if they have not been confirmed to contain normal tissue.     

Allelic alterations of STRs in archival paraffin embedded tissue as DNA source for paternity testing

Owing to a wrong name registered on ID card, the identity of a businessman who had been dead and cremated was suspected, which led his son failed to get legacy. In order to prove the parenthood, the son submitted the gastric cancer tissues surgically removed and embedded in a paraffin block as DNA source for paternity test. After extracting DNA with QIAamp DNA Blood Mini Kit, the 16 STR loci was amplified by two commercial kits of Sinofiler^® (ABI)and Powerplex 16 (Promega), respectively. Both of the STR profiles were similarly showing allelic imbalance pattern at some loci and an additional allele at locus D18S51. The cancerous tissues and adjacent normal tissues were then partitioned off from each other by microscopic analysis of H.E. stained sections and followed by DNA extracting and STR typing, respectively. The allelic alteration could not be found in normal tissues whereas it did in cancerous tissues whose STR profile showed complete loss of one allele (LOH) at loci D13S317 (allele 11 was lost), partial loss of one allele (pLOH) at loci D21S11, D7S820, D19S433, vWA, D12S391 and Amelogein and occurrence of an additional allele (allele 20 was added) at locus D18S51. The results demonstrated that the Paraffin Embedded cancer Tissue used as DNA source for forensic identification is possibly questionable because of their microsatellite instability (MSI) or loss of heterozygosity. It was suggested to partition the normal tissues from the cancer tissues by microscopic evaluation first and then analyzing DNA separately. Comparing the STRs profile of normal tissue with the son's blood sample, the final conclusion was acquired that the donor of the paraffin embedded tissues is the biological father of the son.     

1066例新疆汉族人群21个常染色体STR基因座遗传多态性分析

目的研究21个常染色体STR基因座(CSF1PO,D3S1358,D5S818,D7S820,D8S1179,D13S317,D16S539,D18S51,D21S11,FGA,TH01,VWA,D2S1338,D19S433,D1S1656,D12S391,D2S441,D10S1248,TPOX,D22S1045,SE33)在新疆汉族人群中的遗传多态性。方法用GlobalFiler^TM R PCR Amplification荧光标记试剂盒对1066例新疆汉族无关个体的DNA进行PCR扩增,3500遗传分析仪电泳分析,用GeneMapper■ID-X v1.4软件分析等位基因片段大小,用Modified-Powerstates和Arlequin v3.5分析软件进行等位基因频率和法医学常用参数统计分析。结果在新疆汉族人群中,21个常染色体STR基因座不存在连锁不平衡现象,基因型分布符合Hardy–Weinberg平衡,共检出282个等位基因和1147种基因型,杂合度期望值(He)范围从0.6291(TPOX)到0.9428(SE33),多态信息含量(PIC)范围从0.5648(TPOX)到0.9393(SE33),累计个体识别率(CDP)>0.99999999999999999999。结论新疆汉族人群21个常染色体STR基因座具有较高多态性,可以用于法医学亲权鉴定和个体识别,也可以用于人类学和遗传学研究。     

河南汉族群体6个STR基因座遗传多态性研究

目的　通过研究 6个STR基因座FGA ,TPOX ,D3S135 8,vWA ,D8S1179,D2 1S11的遗传多态性 ,了解它们在河南汉族人群中的多态分布 ,与其他群体进行比较 ,得出遗传距离 ,并了解它在法医学中的应用价值。　方法　采用多聚酶链式反应扩增这 6个基因座 ,采用非变性聚丙烯酰氨凝胶电泳银染显色分析。　结果　得出这 6个基因座在河南汉族人群中的基因频率 ,并计算得出杂合度、个体识别率、非父排除率 ,与其他群体比较得出进化距离。　结论　这 6个基因座有较高的杂合度 ,并且具有相对遗传稳定性 ,在人群中的分布符合Hardy -Weinberge平衡 ,有较高的法医学价值 ,可以应用于个体识别和亲权鉴定。     

青岛地区汉族人群13个STR基因座的频率分布及法医学应用

目的　调查青岛地区汉族人群无关个体的 13个STR基因座 (D3S135 8、VWA、FGA、D8S1179、D2 1S11、D18S5 1、D5S818、D13S317、D7S82 0、D16S5 39、TH0 1、TPOX、CSFIPO)的基因频率分布 ,研究其遗传多态性及其在法医学个体识别及亲子鉴定中的应用价值。　方法　用美国ABI - 310型遗传分析仪对ProfilerPlus和Cofiler两个系统的 13个STR基因座的复合扩增产物进行毛细管电泳及四色荧光自动分析检测 ,基因分型软件为GeneScanv3.1和Genotyperv2 .5 .2。　 结果　获得 13个STR基因座在青岛地区汉族人群的基因频率分布数据 ,13个STR基因座的PIC >0 .5 ,DP >0 .71,CCE =0 .999999,TDP值接近 1,TPm =1.2× 10 -14 ,家系调查符合孟德尔遗传规律。　结论　ProfilerPlus和Cofiler两个系统的 13个STR基因座在法医学个体识别及亲子鉴定中具有较高的应用价值。     

荧光标记复合扩增检测4个STR基因座多态性

目的建立荧光标记复合扩增D1S2142,D13S1492,D14S306,D15S659基因座检测分型方法,并对成都汉族群体4个基因座的遗传多态性进行调查。方法用6-FAM标记D1S2142和D15S659引物,HEX、TMR分别标记D14S306和D13S1492引物,PCR复合扩增,310基因分析仪电泳自动收集电泳结果数据,GeneScan Analysis Software3.7NT软件计算扩增产物片段相对大小,Genotyper(3.7NT软件进行样本基因型分型,建立了荧光标记复合扩增检测4个STR基因座基因型的方法,对145名成都汉族无关个体样本进行分型。结果荧光标记复合扩增D1S2142,D13S1492,D14S306,D15S659基因座,每个STR基因座都获得了清晰的基因型分型结果。145份样本,4个STR基因座分别检出10,14,7,12个等位基因和22,54,21,39种基因型,其基因型分布均符合Hardy-W e inberg平衡。4个基因座在成都汉族群体的杂合度分别依次为0.7793,0.8345,0.7793和0.8345;多态信息含量分别依次为:0.7656,0.8730,0.7470和0.8312。累计非父排除率为0.9783,累计个人识别机率为0.9999 917。结论荧光标记复合扩增D1S2142,D13S1492,D14S306,D15S659基因座,可实现对每个基因座准确分型;成都汉族群体该4个基因座的遗传学数据,可为群体遗传学和法医学研究与应用提供基础资料。     

Allelic distribution of nine short tandem repeat (STR), HLA-DQA1, and polymarker loci in an Omani sample population

Allele frequency distributions of nine short tandem repeat (STR) loci, D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D7S820, and D13S317, HLA-DQA1 and polymarker (PM) loci were studied in a sample population from Sultanate of Oman, Middle East. Blood samples were collected from 162 unrelated individuals. For all STR, HLA-DQA1 and PM loci, no deviations from Hardy-Weinberg equilibrium, based on the exact test, were observed. The most discriminating loci were D18S51 (PD=0.966) and FGA (PD=0.964), while the least informative locus is GYPA (PD=0.585). The allele frequency data may be useful in forensic case work.     

Validation of short tandem repeats (STRs) for forensic usage: performance testing of fluorescent multiplex STR systems and analysis of authentic and simulated forensic samples

The amplification and typing conditions for the 13 core CODIS loci and their forensic applicability were evaluated. These loci are CSF1PO, FGA, TH01, TPOX, vWA, D3S1358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, and D21S11. Results were obtained using the multiplex STR systems AmpFlSTR Profiler Plus and AmpFlSTR COfiler (Applied Biosystems, Foster City, CA), GenePrint PowerPlex (Promega Corporation, Madison, WI), and subsets of these kits. For detection of fluorescently labeled amplified products, the ABI Prism 310 Genetic Analyzer, the ABI Prism 377 DNA Sequencer, the FMBIO II Fluorescent Imaging Device, and the Fluorlmager were utilized. The following studies were conducted: (a) evaluation of PCR parameter ranges required for adequate performance in multiplex amplification of STR loci, (b) determination of the sensitivity of detection of the systems, (c) characterization of non-allelic PCR products, (d) evaluation of heterozygous peak intensities, (e) determination of the relative level of stutter per locus, (f) determination of stochastic PCR thresholds, (g) analysis of previously typed case samples, environmentally insulted samples, and body fluid samples deposited on various substrates, and (h) detection of components of mixed DNA samples. The data demonstrate that the commercially available multiplex kits can be used to amplify and type STR loci successfully from DNA derived from human biological specimens. There was no evidence of false positive or false negative results and no substantial evidence of preferential amplification within a locus. Although at times general balance among loci labeled with the same fluorophore was not observed, the results obtained were still valid and robust. Suggested criteria are provided for determining whether a sample is derived from a single source or from more than one contributor. These criteria entail the following: (a) the number of peaks at a locus, (b) the relative height of stutter products, and (c) peak height ratios. Stochastic threshold levels and the efficiency of non-templated nucleotide addition should be considered when evaluating the presence of mixtures or low quantity DNA samples. Guidelines, not standards, for interpretation should be developed to interpret STR profiles in cases, because there will be instances in which the standards may not apply. These instances include (a) a primer binding site variant for one allele at a given locus, (b) unusually high stutter product, (c) gene duplication, and (d) translocation.     

Evaluation of the PowerPlex Fusion System in a sample from East Timor

East Timor is a country located in Southeast Asia. In this study, we determined allele frequencies and forensic parameters for 24 STR autosomal loci included in the PowerPlex^® Fusion System. Autosomal STR data was collected from saliva samples of 100 individuals from East Timor. The amplification of the 24 autosomal STRs was performed using PowerPlex^® Fusion System (Promega Corporation) and the amplified products were analysed on 3500 Genetic Analyser using GeneMapper^® ID-X 1.2 Software (Applied Biosystems). All the analysed loci meet Hardy–Weinberg equilibrium after Bonferroni correction. In our samples, we found “off-ladder” alleles (D2S441, Penta E and FGA locus) confirmed by reamplification, amplification with others kits and sequenced when justified.     

成都汉族、甘肃东乡族群体D10S1432和D10S1213 位点的遗传多态性分析

目的本研究的目的是了解人类基因组中D10S1432及D10S1213两个STR位点在成都汉族和甘肃东乡族群体中的遗传多态性分布及两个群体之间的关系。方法采用PCR、聚丙烯酰胺凝胶电泳及银染技术,共调查了209例样本。结果在D10S1432位点上观察到5个等位基因,15种基因型。在D10S1213位点上观察到9个等位基因,31种基因型。两位点的基因型频率在调查的两个群体中的分布符合Hardy-Weinberg平衡定律（P>0.05）。经统计,D10S1432在这两个群体中的杂合度为0.664和0.737,个人识别几率为0.827和0.820。D10S1213的杂合度为0.664和0.657,个人识别几率为0.836和0.882。结论结果表明,D10S1432和D10S1213两个位点在法医学个人识别和亲子鉴定中有较高应用价值。     

Development and validation of the AmpFlSTR MiniFiler PCR Amplification Kit: a MiniSTR multiplex for the analysis of degraded and/or PCR inhibited DNA

DNA typing of degraded DNA samples can be a challenging task when using the current commercially available multiplex short tandem repeat (STR) analysis kits. However, the ability to type degraded DNA specimens improves by redesigning current STR marker amplicons such that smaller sized polymerase chain reaction (PCR) products are generated. In an effort to increase the amount of information derived from these types of DNA samples, the AmpFlSTR MiniFiler PCR Amplification Kit has been developed. The kit contains reagents for the amplification of eight miniSTRs which are the largest sized loci in the AmpFlSTR Identifiler PCR Amplification Kit (D7S820, D13S317, D16S539, D21S11, D2S1338, D18S51, CSF1PO, and FGA). Five of these STR loci (D16S539, D21S11, D2S1338, D18S51, and FGA) also are some of the largest loci in the AmpFlSTR SGM Plus kit. This informative nine-locus multiplex, which includes the gender-identification locus Amelogenin, has been validated according to the FBI/National Standards and SWGDAM guidelines. Our results demonstrate significant performance improvements in models of DNA degradation, PCR inhibition, and nonprobative samples when compared to the AmpFlSTR Identifiler and SGM Plus kits. These data support that the MiniFiler kit will increase the likelihood of obtaining additional STR information from forensic samples in situations in which standard STR chemistries fail to produce complete profiles.     

Forensic and population genetic analysis of Serbian population using 21 STR loci of GlobalFiler™ PCR amplification kit

Autosomal short tandem repeats (STRs) have been widely used in forensic investigations. Prior to the application of any DNA based identification method, it is essential to estimate the allele frequencies and forensic statistical parameters of targeted STR loci in each population in order to provide a more precise reference database for forensic investigation. The GlobalFiler™ Kit is a multiplex assay that combines the 13 original CODIS loci with 7 non-overlapping loci from the expanded European Standard Set (ESS), as well as the highly discriminating SE33 locus, two Y-based loci and the sex determining maker, Amelogenin. The full complement of loci in the GlobalFiler™ Kit are: D13S317, D7S820, D5S818, CSF1PO, D1S1656, D12S391, D2S441, D10S1248, D18S51, FGA, D21S11, D8S1179, vWA, D16S539, TH01, D3S1358, AMEL, D2S1338, D19S433, DYS391, TPOX, D22S1045, SE33 and a Y-specific insertion/deletion locus (Yindel). The 6-dye GlobalFiler™ PCR Amplification kit (ThermoFisher Scientific) comprises 21 autosomal STRs have already been proven to be able to provide reliable DNA profiling results and enhance the power of discrimination between individuals. In this study, we are presenting an analysis of GlobalFiler STR loci on 209 unrelated individuals from Serbia.     

Population genetics data of 23 autosomal STR loci for three Populations in United Arab Emirates

In the present study, forensic parameters were estimated for three populations residing in the United Arab Emirates (UAE) including UAE Arabs, Pakistanis and Indians based on the population data of 23 autosomal short tandem repeats (STRs). The UAE Arabs is a vital population to study due to high rates of consanguineous marriages. Therefore, it is essential to estimate the allele distribution and frequencies within this population. In addition, it is crucial to study the largest communities living in the UAE such as Indians and Pakistanis. A total of 1272 blood samples were collected on FTA® cards, comprising of 571 UAE Arabs, 352 Indians and 349 Pakistanis. All of these samples were amplified directly using Verifiler® Express PCR Amplification Kit that focuses on 23 autosomal STR loci, namely D3S1358, vWA, D16S539, CSF1PO, TPOX, D8S1179, D21S11, D18S51, D2S441, D19S433, TH01, FGA, D22S1045, D5S818, D13S317, D7S820, D10S1248, D1S1656, D12S391, D2S1338, D6S1043, Penta D and Penta E loci. The PCR products were electrophoresed on ABI 3500 Genetic Analyzer and analyzed using GeneMapper ID-X v1.4 software. Arlequin v3.5 and PowerStats software were utilized to determine the forensic parameters and population structure using AMOVA. Gene diversity, ranged from 0.67406 (TPOX) to 0.9226 (Penta E) in the UAE Arabs, 0.69955 (TPOX) to 0.9214 (Penta E) in Indian and 0.69853 (TPOX) to 0.921 (Penta E) in Pakistani population. The most discriminating autosomal STR loci observed was Penta E (PD = 0.985), (PD = 0.986), (PD = 0.986) in the UAE Arabs, Indian and Pakistani population, respectively. The obtained results showed the 23 STR loci had a relatively high genetic variation, confirming the suitability for forensic identification and kinship analysis, in the relevant populations. The significance of this study is to build an allelic frequency database for one of the most powerful commercially available STR amplification kits by using the current forensic workflow.     

中国5个群体D20S85基因座的遗传多态性

目的 了解中国5个群体D20S85基因座的群体遗传学数据,比较它们之间的遗传学差异,探讨其在法医学应用中的意义。方法 分别收集5个群体622名无关个体的血样,Chelex-100快速抽提法或饱和酚/氯仿法抽提DNA;扩增后经PAGE垂直板电泳、银染,进行D20S85基因座分型。结果 在5个群体622名无关个体中,共检出9个等位基因,并首次在广东汉族和广西壮族群体中检出等位基因14;每个群体基因频率大于0.05的均为6个,D20S85*6为最常见等位基因。5个群体共观察到35种基因型,群体内基因型频率分布均符合Hardy-Weinberg氏平衡,各群体间基因型构成比无显著性差异。观察140次减数分裂未发现突变。各群体的期望杂合度为0.7720～0.7912;非父排除率,在三联体为0.7538～0.7594,二联体为0.3988～0.4297;个人识别率为0.9175～0,9272;多态信息含量为0.7442～0.7656。应用于亲子鉴定和个人识别案例,效果满意。结论 D20S85基因座是法医学应用价值较高的遗传标记系统。     

Allele frequencies for 70 autosomal SNP loci with U.S. Caucasian, African-American, and Hispanic samples

189 samples from 3 different U.S. sample groups Caucasian (74), African American (71) and Hispanic (44) were typed for 70 autosomal genetic markers. These 70 markers are bi-allelic (C/T) short nucleotide polymorphisms (SNPs). For each sample, the 70 SNP markers were typed in 11 unique 6-plexes and a single 4-plex PCR. A total of 10 of the 210 tests (70 loci x 3 populations) for Hardy-Weinberg equilibrium indicated a statistically significant result. In order to evaluate the minimum number of SNP loci needed to distinguish all 189 samples from one another, we ranked the loci according to their levels of observed heterozygosity and p-values obtained upon testing for Hardy-Weinberg equilibrium. The top 12 loci according to these ranking criteria were tabulated along with the number of unique genotypes observed when combining subsequent SNP markers. The 12 selected SNPs possessed an observed heterozygosity of >0.45 in all three populations examined and thus would be expected to exhibit more differences between samples. All of the 189 samples in this study were individualized with a subset of 12 SNP loci. However, it is likely that the addition of more than 12 SNP loci will be required to resolve larger sets of unrelated individuals from one another. By way of comparison, in these same 189 individuals all but one pair is resolved from one another with three of the traditional short tandem repeat (STR) loci possessing the highest heterozygosity values (D2S1338, D18S51, and FGA) run with the Identifiler kit. The final pair of unrelated samples could be resolved with the combination of 4 STR loci: D2S1338, D18S51, FGA, and VWA.     

13个STR位点在人消化系统肿瘤组织中的变异分析

目的探讨13个CODIS-STR基因座在人消化系统肿瘤组织中的变异情况。方法收集55个个体的消化系统肿瘤组织及其正常组织和血样,Chelex100法提取DNA,用Profiler试剂盒和Cofiler试剂盒进行复合扩增,310型遗传分析仪检测。结果55例肿瘤组织中均存在细胞分裂异常现象,其中有2例肿瘤组织的STR位点发生了变异,变异的类型包括基因型改变、杂合型丢失和杂合双峰不平衡,而且变异可以是多位点同时发生。结论对肿瘤组织类型的样品进行STR分析时,应多加慎重,因为排除的位点可能来自肿瘤组织中的基因突变。     

贵州汉族19个STR基因座多态性及法医学应用

目的调查19个常染色体STR基因座在贵州汉族人群中的等位基因分布,评估其在法医学中的应用价值。方法应用Goldeneye~(TM) DNA身份鉴定系统20A试剂盒,研究贵州520名汉族无关健康个体19个常染色体STR基因座多态性。用310型遗传分析仪进行毛细管电泳,Gene Mapper~ID v3.1进行基因分型。结果 19个常染色体STR基因座的杂合度为0.603 8~0.916 4,个体识别率为0.790 0~0.985 6,非父排除率为0.295 5~0.826 9,多态信息含量为0.553 5~0.908 9,累积个体识别率为1-1.230 0×10~(-22),累积非父排除率为0.999 999 99。贵州汉族和其他五个地域的汉族两两之间等位基因频率比较,仅贵州汉族与山东汉族、辽宁汉族、山西汉族之间存在基因频率差异具有统计学意义。结论 D19S433等19个常染色体STR基因座在贵州汉族人群中具有良好的遗传多态性,对群体遗传学和法医物证学研究有应用价值。     

Allele frequencies of six miniSTR loci of three ethnic populations in Singapore

MiniSTR loci has demonstrated to be an effective approach to recover genetic information from degraded sample, due to the improved PCR efficiency of their reduced PCR product sizes. This study investigated the allele frequency of six miniSTR loci, D1S1677, D2S441, D4S2364, D10S1248, D14S1434 and D22S1045, in three Singapore populations. All loci showed a moderate degree of polymorphism with observed heterozygosity >0.6 for all three populations. The allele frequencies, forensic parameters and heterozygosity comparison with other CODIS STR in similar populations are presented.     

Efficiency Analysis of EX16 +10Y Kit on Detection of the Uygur Population in Xinjiang ProvinceCSCD

Objective: To analyse the efficiency of EX16+10Y kit on the forensic detection of the Uygur in Xinjiang province. Methods: The blood samples were extracted from 4 620 male individuals of Uygur in Xinjiang province, and amplified by EX16+10Y kit. The typing of amplification products was performed by 3130xl genetic analyzer. Results: The genotyping graphs of 15 autosomal STR loci and 10 Y -chromosomal STR loci from 4 620 male individuals of Uygur in Xinjiang province were acquired completely. The genotype distribution of 15 autosomal STR loci was consistent with Hardy-Weinberg equilibrium. The heterozygosity, polymorphism information content and discrimination power of STR loci were 0.637-0.838, 0.580-0.860 and 0.811-0.978, respectively. There were 766 haplotypes in 10 Y -chromosomal STR loci. Conclusion: The test results of EX16+10Y kit is accurate and trustworthy, which can simultaneously be used for the individual identification and the screening of paternal pedigree in practical work. © 2018 by the Editorial Department of Journal of Forensic Medicine.