Evaluation of the DNA stability of forensic markers used in betel-quid chewers' oral swab samples and oral cancerous specimens: implications for forensic application

Chewed betel-quid (BQ) residues are often considered vital biological evidence at crime scenes, since the human DNA extracted from the residues is actually from buccal epithelial cells and can be associated with suspects. BQ-chewing is also a risk factor for oral diseases and/or cancers. Archived medical oral-specimens can be used to identify specific individuals under adverse conditions, although STR markers are known to be unstable in various tumor tissues. This study evaluates the DNA stability of forensic marker systems in BQ-chewers' oral epithelial cells, and in archived clinical specimens of oral cancer patients. The genotypes of oral and paired peripheral blood samples in 200 subjects were compared, using the commercialized typing systems of HLA-DQA1, PM (including LDLR, GYPA, HBGG, D7S8, and GC loci), and AmpFlSTR markers (including 9 STR loci and the Amelogenin gene). The 100 healthy BQ-chewers had consistent oral swab and paired blood sample genotypes analyzed withboth DQA1/PM and STR marker systems. In the 100 oral cancer patients, one discordant result at D7S8 was found in the 600DQA1/PM-marker loci, and 25 allelic alterations with expansion or contraction were detected in the 900 STR loci. The findings herein suggest that when cancerous specimens were tested, the HLA-DQA1/PM system with point polymorphism appears more reliable than the STR system with length polymorphism. Our results also indicate that healthy BQ-chewers' oral cotton swabs containing buccal epithelial cells are useful for forensic purposes using the HLA-DQA1, PM, and STR marker systems.     

Characterization of new miniSTR loci to aid analysis of degraded DNA

A number of studies have demonstrated that successful analysis of degraded DNA specimens from mass disasters or forensic evidence improves with smaller sized polymerase chain reaction (PCR) products. We have scanned the literature for new STR loci, unlinked from the CODIS markers, which can generate amplicons less than 125 bp in size and would therefore be helpful in testing degraded DNA samples. New PCR primers were designed and tested for the STR loci D1S1677, D2S441, D4S2364, D10S1248, D14S1434, and D22S1045, arranged into two miniSTR triplexes. All loci show a moderate degree of polymorphism among 474 U.S. population samples tested and were reliable and sensitive to at least 100 pg of DNA template under controlled laboratory conditions and pristine DNA samples. The utility of these new loci were confirmed in comparing the success of the miniSTR assays for typing degraded bone samples while partial profiles were observed with the majority of the samples using a commercial STR kit.     

STR DNA typing: increased sensitivity and efficient sample consumption using reduced PCR reaction volumes

Improvements in detection limits/sensitivity and lower sample consumption are potential benefits of reducing PCR reaction volumes used in forensic DNA typing of crime scene samples. This premise was studied first with experimental mixtures and a nine-loci megaplex, which demonstrated stochiometric amplification and accurate detection. Next, adjudicated casework samples were subjected to amplification under 15 different template DNA to PCR reaction volume ratios. Reduction of PCR reaction volume and DNA down to 10 microL and 0.500 ng, respectively, produced identical profiles with the same signal intensity and heterozygous allele peak height ratio (HR). Reduction to 5 microL and 0.063 ng yielded HR values that were slightly affected in one to three STR loci. PCR reaction volume reduction can enhance detection and sensitivity while reducing the consumption of irreplaceable crime scene samples.     

荧光标记STR分型技术检验腐败组织基因型

探讨腐败组织荧光标记STR分型检测技术的应用价值。应用含12个STR基因座及一个性别基因座的2个荧光标记的复合扩增系统,对40例1～6周的腐败肌肉提取的DNA进行扩增,用变性聚丙烯酰胺凝胶电泳,PE377测序仪分析基因型。所检测样本在12个STR基因座均扩增出特异性谱带,并可判定其基因型。荧光标记STR检测技术对腐败组织分型可靠,在实际检案中具有较高的应用价值。     

Co-amplification of ENFSI-loci D3S1358, D8S1179 and D18S51: validation of new primer sequences and allelic distribution among 2874 individuals

The present communication presents a new triplex PCR co-amplifying three loci (D3S1358, D8S1179 and D18S51) recommended for STR typing by the European Network of Forensic Science Institutes (ENFSI). Twenty-two different primers were tested to optimise the PCR. Four of the six primer sequences finally chosen were self selected, the fifth was a published one and the sixth derived from a commercially available multiplex kit. Using this PCR-setup, even minimum amounts of genomic DNA are sufficient to analyse the STR loci D3S1358, D8S1179 and D18S51 in parallel. Especially in forensic casework, where DNA is mostly limited and often contaminated with enzyme inhibitors, this new PCR proved to be very advantageous. To demonstrate the reliability, buccal swabs from 2874 persons were typed not only with the new triplex PCR but also with a commercially available multiplex kit.     

2个Y-STR基因座在成都汉族群体中的遗传学研究

目的　为了寻求新的适合于法医学应用的Y染色体STR基因座 ,我们调查了基因座DYS44 2和DYS44 6在成都群体中的分布。　方法　样本来自于成都地区汉族无血缘关系的个体 ,通过Chelex法提取样本DNA ,利用PCR扩增硝酸银染色方法进行分型。　结果　DYS44 2是一个四核苷酸简单重复基因座 ,而DYS44 6则为五核苷酸简单重复基因座。男性样本都出现了谱带 ,而女性样本则无PCR产物。DYS44 2基因座和DYS44 6基因座变异度分别为 :0 .6 86 7、0 .75 5 2。　结论　DYS44 2和DYS44 6是非常适合于法医学应用的STR基因座。     

Development of the Investigator STR GO! Kits for the direct amplification of reference samples

STR analysis of forensic reference samples can be performed using a novel direct amplification method. Two assays have been developed for this purpose. One covers the CODIS set of markers and the other covers the ESS including SE33. The method gives balanced DNA profiles with high first pass rates for buccal swabs and blood and buccal cells on FTA paper. The addition of SNP primers compensates for profile imbalances caused by three known binding site mutations.     

改良IPEP法用于痕量DNA检测的实验研究

目的探讨改良扩增前引物延伸(IPEP)法对痕量DNA样本STR检测分型的效果。方法用改良IPEP法对痕量样品DNA进行全基因组扩增(WGA),扩增产物用实时荧光定量PCR技术定量、用AmpFLSTR~ Indentifiler~试剂盒作基因型检测。结果该方法可增加模板DNA约200~1100倍。基因组DNA不低于0.025ng时,可获得15个STR基因座和Amelogenin性别基因座的分型结果。基因组DNA0.01~0.025ng时,可获得9个以上基因座的分型结果。结论改良IPEP法可有效提高痕量DNA样本STR分型检验的灵敏度,有较好的实用价值。     

STR位点D19S253和D8S1179的法医学意义及应用研究

为评估STR位点D19S253和D8S1179的法医学应用价值，应用PCR和PAG垂直电泳技术对两位点的种属特异性，检测灵敏度，以及同一个体不同组织分型的同一性及不同基质和不同保存时间的斑痕分型等与法医应用有关的问题进行了研究，D19S253和D8S1179位点的检测灵敏度分别为0．25ng及0．5ng，同时两位点具有较高的种属特异性，同一性及较好重复性，且能够复合扩增，表明D19S253和D8S1179是法医学检案中较实用的两个STR标记。     

超滤管在陈旧生物检材中的应用

目的探讨millipore超滤管滤过方法对陈旧生物检材DNA分型检验的应用价值。方法将23份陈旧血样分别剪取同样合适大小的血片3组,标为A、B、C组,磁珠法提取DNA,分别用80μL、80μL、20μL洗脱液洗脱得到模板DNA,其中A、C组模板直接扩增,B组用millipore超滤管滤过浓缩后扩增。PCR产物用AB3130x L基因分析仪检测,Gene Mapper ID V3.2软件进行自动分型。所得实验数据用SPSS软件分析处理。结果 A组没有1例样本扩出全部STR基因座,B组有18例样本扩出全部STR基因座,C组有11个样本扩出全部STR基因座。结论应用millipore超滤管滤过方法可以明显提高陈旧生物检材的DNA分型成功率。     

Use of the genomic matching technique to complement multiplex STR profiling reduces DNA profiling costs in high volume crimes and intelligence led screens

The genomic matching technique (GMT) targets duplicated polymorphic sequences within genomic blocks in the human major histocompatibility complex (MHC), differentiating between individuals at the DNA level using a single primer pair per block. The GMT is currently used to supplement human leukocyte antigen (HLA) typing to match donor and recipient pairs for bone marrow transplantation and has the potential to be employed as a powerful exclusion tool in forensic biology. The GMT is highly reproducible, produces DNA profiles from less than 1 ng of DNA and was successfully employed to profile a range of forensic samples including buccal swabs, handled objects and fingerprints. Furthermore, GMT profiles from a single genomic block in the MHC are likely to be more discriminatory than known highly polymorphic short tandem repeat (STR) loci such as ACTBP2. As such, the GMT can reduce the cost of investigations that require profiling of multiple suspects or samples from one or more crime scenes and could be extended to profile genomic blocks in other polymorphic genetic systems in the human genome.     

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.     

运用酚-氯仿法结合磁珠法提取蝇蛆体内人类DNA

目的建立运用酚-氯仿法结合磁珠法从蝇蛆嗉囊内提取人类DNA的方法,从而提高STR分型检验的灵敏度。方法采用酚-氯仿法对蝇蛆嗉囊内容物中的人类DNA进行提取,提取产物经磁珠法纯化浓缩后用QuantifilerTM人类DNA定量试剂盒在7500型实时荧光定量PCR仪上进行PCR定量,再用AmpF■STR IndentifilerTM试剂盒在3130XL-Avant遗传分析仪上对这些DNA样本进行STR分型。结果本研究建立的方法可增加模板DNA浓度约为单独使用酚-氯仿法的2倍。用此方法提取到的DNA浓度[（0.218±0.041）ng/μL]可获得全部16个STR分型结果。结论酚-氯仿法结合磁珠法可以有效地提高提取到的人类DNA样本STR分型检验的灵敏度,对于从事法医昆虫学方面研究的工作者有较好的实用价值。     

ABO基因分型与多重STR联合检测在法医学中的应用

目的建立ABO基因型和Goldeneye16A试剂盒联合检测的方法,并评价其在法医学实践中的应用价值。方法将6种ABO基因型(A/A,A/O,B/B,B/O,A/B,O/O)的序列特异性引物(PCR-SSP)检测方法与Goldeneye16A试剂盒相整合进行同步分型。通过对460份男性个体血痕样本、9947A DNA及90份案件样本进行检测,考察方法的一致性、灵敏度及对法庭科学检材的适用性。结果应用本文方法可同时检出6种ABO基因型和15个常染色体STR基因座及性别决定基因座,检测灵敏度为125pg,其中ABO基因检测灵敏度达63pg。460份男性血痕和90份案件检材证实该联合分型方法用于各类检材结果准确、稳定。结论本文ABO基因分型与多重STR联合检测方法,适用于各类含有核细胞的生物检材,在法庭科学DNA鉴定中有较好的应用前景。     

多重置换扩增技术用于法医学微量DNA检测效果

目的探讨多重置换扩增(MDA)技术对法医学微量DNA样品STR检测分型的效果。方法用MDA技术对不同模板量DNA进行全基因组扩增(WGA),扩增产物用实时荧光定量PCR技术定量、用Profiler PlusTM试剂盒检测基因型。结果该方法可对模板DNA增加104～106倍。1ng样品DNA的MDA产物可获得9个STR基因座和Amelogenin性别基因座的准确分型结果;低于0.1ng的样品DNA经MDA扩增后,基因座检出数增加,但可见等位基因不平衡或丢失现象。结论MDA技术可有效增加DNA模板量和提高微量DNA分型效果。但样品DNA量低于0.1ng时,MDA产物的STR分型结果判读须慎重。     

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。     

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。     

6个新的STR基因座复合扩增体系的建立及应用

目的构建6个常染色体STR基因座的荧光复合扩增体系,应用于法医学DNA检验。方法筛选6个STR基因座D4S2366、D3S3045、D18S1002、D20S481、D22S689、D4S2639,根据复合扩增要求设计引物并采用不同荧光染料进行标记,经过反复调整和优化,建立6基因座荧光复合扩增体系,并用该复合扩增体系对224名华东汉族无关个体进行分型,计算出常用法医遗传学参数。结果使用该荧光复合扩增体系,在224名华东汉族无关个体中,6个STR基因座D4S2366、D3S3045、D18S1002、D20S481、D22S689、D4S2639分别检出7、8、9、10、9、9个等位基因和21、26、21、23、28、32种基因型,基因型分布符合Hardy-Weinberg平衡。杂合度（H）分布为0.714～0.808,个体识别率（DP）为0.874～0.934,二联体非父排除率（PED）为0.310～0.453,三联体非父排除率（PET）为0.485～0.628,多态信息含量（PIC）为0.672～0.784,二联体累积非父排除率（CPED）为0.947689,三联体累积非父排除率（CPET）为0.993345,累积个人识别能力（CDP）为0.999999543。结论构建的荧光复合扩增体系具有较高的法医学应用价值,D4S2366等6个常染色体STR基因座在华东汉族群体中均具有高度多态性,可作为常规商品化试剂盒的有效补充,用于突变情形的亲权鉴定以及依据亲权指数值不能明确鉴定意见的亲权鉴定。     

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。     

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.