Amelogenin等位基因丢失的研究现状

Amelogenin基因座作为性别标记包含于常用的商品化STR分型试剂盒中,被应用于法医亲子鉴定、个体识别和DNA数据库等。大量报道显示Amelogenin基因可发生变异,导致X染色体或Y染色体特异性产物扩增失败,即AMELX或AMELY丢失。AMELY丢失可导致性别判断错误,性别错判可误导侦查方向。下面对近年来国内外Amelogenin基因座等位基因丢失现象的研究现状进行综述,探讨Amelogenin基因座的变异频率、变异类型、变异机制及其对性别鉴定的影响和应对方法,为准确地进行法医物证性别鉴定提供帮助。     

脱落上皮细胞类生物检材的自动化提取

目的建立一种自动化提取脱落上皮细胞类生物检材DNA的方法。方法附着于不同载体上的脱落上皮细胞类生物检材共278份,应用Eppendorf epMotion 5075LH工作站结合DNA IQTM系统提取模板DNA,并用Identifiler试剂盒进行STR检验。结果在278份被检的生物检材,其中126份检材获得13个基因座以上的STR分型,不同类型的检材其检出率不相同,最高达73.44%,最低为10.89%。结论脱落上皮细胞类检材应用自动化工作站提取DNA模板可在法医日常检案中广泛应用。     

浓缩DNA法结合miniSTR分型技术检验微量DNA

目的优化低拷贝数DNA STR分型方法。方法对采用磁珠法或Chelex-100法提取DNA,Identi-filer试剂盒扩增,未获得分型结果的日常检案检材,采用物理浓缩法或过柱浓缩法浓缩DNA,采用miniFilerTM试剂盒再次扩增分型。结果 127例检材中,47例磁珠法提取DNA未获得分型的样品,分型成功率为36%;80例Chelex-100法提取DNA未获分型的样品,分型成功率为30%。结论采用浓缩法和miniFilerTM试剂盒,可以提高日常检案中低拷贝数检材的STR检验分型成功率。     

PowerPlex~ 21试剂盒扩增后的分型图谱中Y片段丢失的识别

目的依据分型图谱,直观、简便识别是否存在Amelogenin基因Y片段丢失的可能。方法采用计算分型图谱中等位基因峰高之和比值的方法,统计1 968份人员样本经Power Plex~ 21试剂盒扩增后Amelogenin与D3S1358基因座之间的均衡性、Amelogenin X等位基因与Amelogenin Y等位基因的均衡性以及D3S1358基因座不同等位基因的均衡性情况。结果 90.8%的女性样本Amelogenin X等位基因峰高不低于D3S1358基因座等位基因峰高和的60%,94.9%的男性样本Amelogenin X等位基因的峰高不超过D3S1358基因座等位基因峰高和的70%。结论 Power Plex~ 21试剂盒扩增后的分型结果中,当Amelogenin基因只检测到Amelogenin X等位基因,且Amelogenin X等位基因的峰高不及D3S1358基因座等位基因峰高之和的70%时,应考虑存在Y片段丢失的可能性。     

汗潜指印的STR分型检测在案件中的应用

目的探索案例中所涉及的汗潜指印DNA的提取和检验方法。方法采用Chlex-100法提取DNA,进行STR复合扩增,通过毛细管电泳检测荧光信号。结果案例中涉及的汗潜指印在ProfilerPlus试剂盒10个基因座的分型检测均获成功。结论含有汗潜指印的检材的发现和正确提取对最终检测成功至关重要。     

D8S1179基因座等位基因“丢失”1例

作者报道1例D8S1179基因座基因丢失现象：采用ProfilerPlus试剂盒扩增系统对1例血痕D8S1179基因座进行基因分型时，等位基因16丢失；改用Identifiler试剂盒扩增系统对其进行基因分型时，等位基因16正常出现。     

限制性组合分析法推定男女混合斑中个体分型初探

正混合斑是指包含两名或两名以上个体的混合生物检材,在多数情况下,此类检材的DNA分型往往表现为两人或多人的混合分型,使结果分析较为复杂[1]。本文尝试采用2005年国际法医遗传学会(ISFG)推荐的关于混合斑结果分析中的计算方法对混合斑案件中单一个体DNA分型结果进行分析。1材料与方法1.1样本及检验样本由公安部物证鉴定中心提供强奸案件中床单上混合斑检材1份,为日常检案积累,根据案情调查证实该检材系混合斑。DNA检验采用Chelex法提取上述检材DNA,经DNATyperTM15 plus试剂盒扩增后在ABI 3130遗     

用Chelex100法及有机溶剂提取法联合提取DNA扩增STR基因座的比较研究

为了比较不同方法提取DNA扩增STR基因座的成功率 ,本文用Chelex10 0法及Chelex10 0法联合有机溶剂提取法分别提取性犯罪案件 6份血斑及 6份混合斑中精子DNA ,并用PE公司ProfilerPlus系统复合扩增 ,ABI 310型基因分型仪检测。结果表明 ,常规采用Chelex10 0法提取血斑及精斑等生物检材DNA作STR基因座检验失败或所检测的位点较少时 ,应对Chelex10 0法提取的DNA上清液再用有机溶剂提取法提取 ,可极大提高DNA检验成功率。采用本文建立的Chelex10 0法联合有机溶剂提取法 ,提高了PCR扩增阳性率 ,对实际检案很有帮助 ;在PCR扩增前应常规进行DNA定量检验 ,否则对于重要检材应进行梯度扩增。     

5 μl PCR反应体系的建立

PCR技术最大的优点是使目的DNA片段成百上千万倍增加,尤其适合于微量检材检验,该技术已成为常规法医物证检验技术。实际检案中,多余的PCR扩增产物没有用处,更是为了节约成本,我们微量化了ProfilerPlus试剂盒反应体系至５μl,报道如下,供参考。１材料与方法１．１材料送检案件滤纸提取血样１０份,混合斑检材为花短内裤１条,卫生纸２份,阴道擦拭纱布２份,地上提取精斑１份,镜下均检见人精子。所用试剂、仪器为：ProfilerPlus试剂盒;９６００型PCR仪;３１０型遗传分析仪。１．２方法（１）用Chelex１００法提取１０份血斑…     

Y—STR基因座分型缺失分析

目的分析Y—STR基因座等位基因分型缺失数据,为法医学提供应用参考。方法收集浙江汉族4477名无关男性个体血样,自动工作站磁珠法提取DNA,Y—filer^TM试剂盒进行复合扩增,Gene Mapper IDv3．2分析软件分析Y-STR数据,统计出现基因分型缺失的概率。结果在4477名无关个体的Y—STR数据中,有来自23种单倍型的26个样本Y-STR分型各有1个短片段基因座的基因分型缺失,而其它长片段基因座的分型均完全正常。基因分型缺失的发生频率为0．518％。结论Y-STR基因座分型缺失具有一定的发生率,在日常检案中应注意防止误判。     

Profiler Plus系统在法医学DNA检验中的问题探讨

以Profiler Plus系统生产厂商提供的检验条件,在实际工作中对大规模样品进行了检验分析.结果显示该系统尚存在等位基因丢失、额外等位基因、同一荧光标记不同基因座等位基因重叠公布、罕见等位基因与亚型等非技术操作性问题.对有关样品应用Power Plex1.2,Power Plex16系统进行了检验验证.     

A rare mutation in the amelogenin gene and its potential investigative ramifications

Over the past few years, the Australian forensic science community has adopted a common methodology and technology in the application of DNA profiling for investigative and forensic purposes. The ultimate objective of this initiative is the establishment of a national DNA database similar to that used in the UK. An integral part of this methodology is the use of "Profiler Plus," a nonaplex of STRs combined with amelogenin, a locus utilized for sex determination. This paper reports the results from a case where a mutation in the annealing region of the amelogenin primers appears to have resulted in the failure to amplify the amelogenin Y-homolog from a phenotypically normal male. The result was confirmed using two different primer sets that amplify different regions of the amelogenin gene. This situation suggests that the genetic determination of sex based on the amelogenin sequences from specimens of unknown origin, such as crime scene samples, should not be considered infallible.     

A time course study on STR profiles derived from human bone, muscle, and bone marrow.

The use of the polymerase chain reaction (PCR) to define deoxyribonucleic acid (DNA) types at several loci was investigated. PCR was used to amplify nine short tandem repeat (STR) loci along with the amelogenin locus on the X and Y chromosomes using the AmpF/STR Profiler Plus PCR amplification kit (Perkin Elmer). Rib bones were collected from 12 individuals. Five cm portions were buried at a depth of approximately 30 cm and 5 cm portions were left on the surface of the ground. Samples were exposed to the environment for periods of time ranging from two weeks to 17 months. Dried blood standards were prepared for use as reference standards for each rib sample. Bone, muscle, and bone marrow were collected from each sample. DNA from each tissue type was extracted. Complete profile results were obtained from the surface bone samples out to an exposure time of 17 months. None of the muscle or bone marrow samples produced complete profile results beyond eight weeks. All DNA typing results from complete or incomplete profiles were consistent with DNA typing results of the corresponding blood standard. Results suggest that using the AmpF/STR Profiler Plus PCR Amplification Kit is a valid way to establish the DNA profile of tissue types from human remains.     

Performance evaluation of two multiplexes used in fluorescent short tandem repeat DNA analysis

The performance of two commercial multiplex kits that together amplify the 13 core short tandem repeat (STR) loci currently in use by forensic laboratories and the U.S. national Combined DNA Indexing System (CODIS) were evaluated. The typing systems examined were AmpFlSTR Profiler Plus and AmpFlSTR COfiler (PE Applied Biosystems, Foster City, CA). Electrophoretic separation and detection of the fluorescent PCR products was achieved by capillary electrophoresis (CE) using an ABI Prism 310 Genetic Analyzer. The studies addressed the on-site validation of the instrument, the software, and each typing system. These studies included instrument sensitivity, resolution, precision, binning, peak height ratios, mixtures, stutter, and the amplification of non-probative and simulated forensic samples. Other additional developmental-type work is also reported herein, such as species specificity testing and amplification of environmentally insulted samples. Amplification conditions were found to be robust and the primer sets shown to be specific to human DNA. Stutter and peak height ratios fell within limits published by the manufacturer and other laboratories. The data demonstrate that the CE instrument can consistently resolve fragments differing in length by one base and that the +/-0.5 base bin used by the Genotyper software is acceptable for making accurate allele calls. Correct typing results were obtained from non-probative and simulated case samples, as well as samples exposed to outdoor environmental conditions. The results support the conclusion that DNA extracted from biological samples routinely encountered in the forensic laboratory can be reliably analyzed with AmpFlSTR Profiler Plus and COfiler using CE.     

STR primer concordance study.

Over 1500 population database samples comprising African Americans, Caucasians, Hispanics, Native Americans, Chamorros and Filipinos were typed using the PowerPlex 16 and the Profiler Plus/COfiler kits. Except for the D8S1179 locus in Chamorros and Filipinos from Guam, there were eight examples in which a typing difference due to allele dropout was observed. At the D8S1179 locus in the population samples from Guam, there were 13 examples of allele dropout observed when using the Profiler Plus kit. The data support that the primers used in the PowerPlex 16, Profiler Plus, and COfiler kits are reliable for typing reference samples that are for use in CODIS. In addition, allele frequency databases have been established for the STR loci Penta D and Penta E. Both loci are highly polymorphic.     

3种常用PCR扩增试剂盒检验血样DNA的结果比较

目的探讨常用的ProfilerPlusTM、IdentifilerTM与Powerplex(16试剂盒检验血样DNA的差异。方法510名无关中国汉族个体血样,分别用ProfilerPlusTM与Powerplex(16试剂盒进行DNA检验,然后对有不同检验结果的同一样本,再用ProfilerPlusTM、IdentifilerTM与Powerplex(16等三种试剂盒进行检验,并比较其结果。结果在510名个体血样的DNA检测结果中,发现同一样本有不同结果的有7例,其差异率为1.3725%;ProfilerPlusTM、IdentifilerTM与Powerplex(16各有1例在D13S317或FGA基因座上出现等位基因缺失现象,缺失率为0.1961%;ProfilerPlusTM有5例在D8S1179基因座上出现扩增严重不平衡现象,相应的IdentifilerTM与Powerplex(16试剂盒的检验结果为正常杂合子。结论ProfilerPlusTM、IdentifilerTM与Powerplex(16试剂盒检验血样DNA均会出现扩增不平衡和/或基因丢失现象,其发生几率IdentifilerTM与Powerplex(16试剂盒较ProfilerPlusTM少。     

TWGDAM validation of the AmpFlSTR Profiler Plus and AmpFlSTR COfiler STR multiplex systems using capillary electrophoresis

Prior to forensic implementation, a profiling system requires validation following the recommendations presented by the Technical Working Group on DNA Analysis Methods (TWGDAM). In this work two such systems, AmpFlSTR Profiler Plus and AmpFfSTR COfiler have been validated according to the guidelines provided by TWGDAM. Profiler Plus and COfiler simultaneously amplify nine and six STR loci respectively; both also amplify a portion of the amelogenin gene. Performance of the two STR multiplex systems under conditions set forth by TWGDAM was robust and reproducible, indicating that these systems are suitable for use in forensic analysis. Additionally, specific sections of the TWGDAM validation guidelines are especially valuable in terms of familiarizing users with particular limitations of the systems prior to taking on casework.     

烟蒂DNA分型的研究

目的 研究烟蒂中DNA提取及其检验。方法 用Chelex-100法提取170枚烟蒂样本的DNA,进行PCR扩增及STR检验。结果 除1名志愿者提供的21枚烟蒂外层纸未能检出STR基因分型外,其余烟蒂外层纸均得到分型结果。加入少许烟丝的样本未能检出STR分型,与口唇接触的海绵有时可检出基因型,6个月内的烟蒂可检出小片段基因座。结论 烟蒂能进行DNA分型,在法医检案中具有应用价值。     

Report of the blind trial of the Cetus Amplitype HLA DQ alpha forensic deoxyribonucleic acid (DNA) amplification and typing kit

The AmpliType HLA DQ alpha forensic DNA amplification and typing kit is designed for the qualitative analysis of the human leukocyte antigen (HLA) DQ alpha alleles present in deoxyribonucleic acid (DNA) extracted from forensic samples. The AmpliType kit is the first forensic DNA typing product based on the GeneAmp polymerase chain reaction (PCR) process. The kit was evaluated by five forensic science laboratories (test sites) to assess their ability to perform DNA typing using PCR on sample types typically encountered by forensic laboratories. None of the DNA-containing samples was mistyped. Of the 180 DNA-containing samples analyzed, results were reported for 178 (98.9%). Of the 178 samples with results, all were correctly typed. Two sites did not report a result for one sample each. Four of the five laboratories experienced no significant levels of contamination in the DNA-containing samples. At the one site with the highest number of DNA-containing samples with contamination, the typing results were not compromised. This site was able to correct the contamination problem through simple procedural changes and stricter attention to sterile technique. Blank controls were important to monitor contamination. In conclusion, the trial demonstrated that forensic science laboratories are capable of setting up a PCR-based DNA typing laboratory and successfully using the AmpliType HLA DQ alpha forensic DNA amplification and typing kit to analyze forensic samples.     

Identification of a D8S1179 primer binding site mutation and the validation of a primer designed to recover null alleles

A population study of Chamorros and Filipinos using short tandem repeat (STR) loci amplified with the AmpFlSTR Profiler Plus PCR amplification kit demonstrated an excess of observed homozygosity at the D8S1179 locus. Use of a different set of D8S1179 primers to type the same samples did not demonstrate an excess of homozygosity and showed discordant genotypes at the D8S1179 locus. A single point mutation, G-to-A transition, 16 nucleotides from the 3' end of the reverse primer, was identified to cause allele dropout when using the AmpFlSTR Profiler Plus primer set. An additional D8S1179 reverse primer specific for the variant was constructed resulting in the recovery of the null allele. The primer was included in the newly developed AmpFlSTR Identifiler PCR amplification kit. No deleterious effects or non-specific peaks were observed in validation experiments evaluating primer concentration, Mg2+ concentration, annealing temperature and population samples.