片段长度差异等位基因特异性PCR——一种改良的SNP分型新方法

目的建立一种基于等位基因特异性PCR原理的改良SNP分型新方法:片段长度差异等位基因特异性PCR,并考察特异性引物的3'端第3位、第4位碱基错配对特异性延伸的影响。方法以SNP位点rs759117和rs760887为例,设计两条长度不同、3'末端分别与SNP两个等位基因碱基配对的上游引物,同时在两个等位基因特异性引物3'端第3或第4位碱基引入错配以增加特异性,下游为公用引物。PCR产物经聚丙烯酰胺凝胶电泳、银染显带后确定样本的基因型。结果不同SNP纯合子为长度不同的单一谱带,杂合子则为两条带,其结果与直接测序完全一致。两条特异性上游引物3'端第3或第4位碱基引入错配后非特异性延伸显著减少,且对PCR反应条件的严格性要求明显降低。结论片段长度差异等位基因特异性PCR是一种简单快速而有效的SNP分型新方法;两条特异性引物3'端第3、第4位碱基引入错配可使特异性显著增加     

基于等位基因特异性PCR原理建立的SNP分型新方法

目的建立一种新方法,对多个单核苷酸多态性(singlenucleotidepolymorphism,SNP)位点进行分型。方法基于等位基因特异性PCR原理,采用荧光标记复合扩增和毛细管电泳技术,根据PCR片段长度差异进行分型。选择SNP位点共11个,每个SNP位点设计两条长度不同、3’末端分别与SNP两个等位基因碱基配对的上游引物,同时为了增加特异性,在两条等位基因上游引物的3’末端第3或第4位碱基人为引入错配。在距离上游引物100～300bp范围内的合适位置,设计下游共用引物,并进行荧光标记。所有位点经过复合扩增后,PCR产物经ABIPrismTM310型遗传分析仪电泳分离,确定每个SNP的基因型。结果每个SNP位点纯合子为单一产物峰,杂合子则为长度不同的两个产物峰。不同的SNP位点扩增产物长度不同,根据产物长度和产物峰的数量进行SNP分型,一次完成11个SNP位点分型,其结果与直接测序完全一致。结论荧光标记复合扩增片段长度差异等位基因特异性PCR法是一种简单快速而有效的SNP分型新方法。     

AS-PCR技术检测20个mtDNA SNP位点及单倍型频率

目的基于等位基因特异性PCR(allele-specific PCR,AS-PCR)技术,建立一种三色荧光标记复合扩增检测线粒体DNA(mtDNA)SNP的方法。方法基于AS-PCR原理,选择20个mtDNA编码区SNP位点,分为两组,分别标记FAM和HEX荧光,每个位点设计具有长度差异的两条上游(下游)等位基因特异性引物以及一条下游(上游)通用引物。结合AS-PCR技术和毛细管电泳,检测200份无关个体血样。各位点随机选取至少3个样本进行直接测序验证,并进行单倍型频率调查。结果 200份血样均得到清晰分型,各位点的检测结果与直接测序结果完全一致。10μL体系下,DNA最低检测浓度为0.2pg,当模板量为0.5~5 pg时能得到较为理想的分型图谱。在200名无关个体中,共分出15种单倍型,单倍型多样性为0.906 0。结论 AS-PCR技术是一种简单、快速且有效的mtDNA SNP分型方法,适用于法庭科学检验的需求。     

人和动物SON基因3’非编码区的PCR测序分析

目的 研究人和猕猴、阿拉伯狒狒、猪、牛、羊、马、驴、骡、狗、猫、兔、大白鼠、小白鼠、豚鼠等14种哺乳类动物SON基因3’非编码区(3’UTR)的种属特异性碱基序列差异。方法 对人和上述14种哺乳类的SON基因3’非编码区中的部分种属特异性区域进行PCR测序分析。结果 人有2条扩增片段和14种哺乳类动物各有1条扩增片段的碱基序列;人无关个体和同一种属不同个体动物DNA扩增片段的碱基序列相同,人、猕猴、阿拉伯狒狒、猪、牛、羊、马、驴、骡、狗、猫、兔、大白鼠、小白鼠、豚鼠DNA的SON基因3’UTR扩增片段之间存在碱基序列差异。结论 SON基因3’UTR是一个具有良好种属特异性的遗传标记,采用SON基因3’UTR扩增测序技术可以对人和上述14种哺乳类动物进行准确的种属鉴定。     

D18S51基因座等位基因侧翼序列四碱基缺失3例

3例无关人员口腔拭子经DNA提取后采用AGCU EX20、AGCU EX30、VeriFiler Plus和PowerPlex^?21四种试剂盒检测，同一样本在D18S51基因座获得了相差1个重复单元的两种等位基因分型。本文利用Sanger测序法分别对上述3例人员样本的D18S51基因座及上下游区域进行检测。经序列比对，发现3个样本的基因组中D18S51基因座下游chr18:63281892-63281895位置均存在[GTTT]的四碱基缺失。建议针对D18S51基因座设计引物时，应选择在上述碱基缺失位置上游区域进行。     

基于通用报告引物的5个Y-SNP复合扩增及其单倍型

目的建立一种简便、经济、高效的SNP复合扩增体系,为法医学应用打下方法学基础。方法选择5个Y-SNP位点——IMS-JST164520、IMS-JST021354、IMS-JST003305、M119和M134,针对每一位点设计5′端带有通用报告引物(universal reporter primer,URP)的等位基因特异性引物,先利用等位基因特异性PCR技术扩增不同位点的等位基因片段,再利用荧光标记的URP扩增检测所有位点的等位基因。结果成功构建了5个Y-SNP荧光复合扩增体系,分型结果显示:同一SNP位点的两个不同等位基因表现为不同颜色的产物峰,不同SNP位点间等位基因片段长度不同。5个Y-SNP在武汉汉族群体中的单倍型多样性为0.8655。结论基于URP的SNP复合扩增体系具有简便、经济、高效的特点,具有较高的法医学应用价值。     

miniSTR荧光检测体系的建立及法医学应用

目的 建立检测片段均小于150bp的miniSTR荧光检测体系,提高对微量降解检材DNA的检测效能. 方法 应用Primer Premier 5软件设计、FastPCR 6.0筛选引物,组合成用四色荧光标记引物的miniSTR复合扩增体系.优化PCR检测条件和引物浓度,在3100-Avant仪上用POP4胶进行电泳检测.分型结果用DNA标准品9947A和007进行验证,并通过检测新鲜血样、疑难微量检材评估该体系的法医学应用效能.结果 建立的miniSTR荧光检测体系（D12A TA 63、D2S1776、D1GA TA 113、D4S2408、D17S974、D20S482、D3S3053、Ame logenin、D6S474、D9S1122）中各基因座的检测片段均小于150bp,各等位基因扩增均衡性良好,无非特异性扩增产物,等位基因频率分布符合Hardy-Weinberg平衡,累积个体识别率为0.999999983,三联体累积非父排除率为0.996 8.能成功检测腐败肌肉组织、低拷贝数DNA检材以及在40％甲醛溶液中固定12d的人体组织. 结论 miniSTR荧光检测体系可独立应用于降解DNA样本的个体识别鉴定或补充应用于亲权鉴定,提高对微量、降解检材DNA的检测能力.     

荧光标记的ASP-PCR法对ABO基因分型的研究

目的建立一种方便准确的ABO基因分型检验方法。方法选取ABO基因外显子6和7上的3个位点nt261、nt297和nt803,分别对第6和7外显子进行扩增,并对扩增产物进行测序得出样本的基因型;然后用荧光标记的等位基因特异性引物对已知基因型的样本进行扩增,并用3130遗传分析仪进行电泳分析。结果该方法检出的基因型与测序得出的基因型完全一致。结论等位基因特异性引物法分型结果准确,特异性高,可用于法医学中对犯罪嫌疑人的筛查。     

荧光标记3个miniSTR基因座复合扩增系统的建立

目的建立扩增片段<135bp,包括D5S818,D8S1179,D16S539 3个miniSTR基因座复合扩增系统。方法采用不同荧光染料标记引物,通过PCR扩增,利用ABI 3100遗传分析仪进行片段长度分析,对100份无关个体血样,10个家系样本以及30份高度降解检材进行检测。结果本系统DNA分型结果与AmpFLSTR Identifiler试剂盒完全一致,且灵敏度高于AmpFLSTR Identifiler试剂盒。结论本系统可以应用于个人识别和亲权鉴定,为降解DNA样本分型提供了新的方法。     

SNP-STR遗传标记复合扩增体系的构建及法医学应用

目的筛选并构建与目前STR数据库兼容的SNP-STR遗传标记复合扩增体系,调查其在四川汉族群体中的遗传多态性,并探讨其在混合DNA样本分析中的应用价值。方法以现有商业试剂盒中使用的STR遗传标记为基础,筛选与STR遗传标记相邻的SNP位点并组成SNP-STR遗传标记。运用SNP等位基因设计特异性引物,构建基于等位基因特异性扩增的SNP-STR遗传标记复合扩增体系。调查该体系在四川汉族群体的遗传多态性,并评价不同位点数目的体系对两个体混合DNA样本的检测效能。结果筛选并构建了由13个SNP-STR遗传标记构成的等位基因特异性复合扩增体系。在四川汉族群体中,各位点杂合度为0.76～0.88,累积个体识别率达0.999 999 999 999 999 968。在对两个体混合DNA的分析中:单位点扩增时,混合样本的混合比例达到1 000∶1时依然可以检测到少量成分所特有的分型;多位点复合扩增时,混合比例最大可达500∶1;随着体系中位点数量的增加,对混合DNA中少量成分的检测效能降低。结论SNP-STR遗传标记较STR具有更高的多态性,其构成的复合扩增体系对混合样本的分析效能优于传统的STR复合扩增体系。     

用新设计引物调查武汉汉族Penta D和Penta E基因座遗传多态性

目的　研究PentaD和PentaE基因座分型引物设计 ,调查PentaD和PentaE基因座在武汉汉族人群中的遗传多态性。方法　用重新设计的PentaD和PentaE基因座分型引物 ,采用热启动PCR和PAGE技术对 2 81名武汉地区汉族无关个体进行分型调查 ,并将其分型结果与Promega公司的PowerPlexTM16系统荧光标记复合扩增试剂盒分型结果进行比较。结果　新设计引物扩增产物的片段大小范围分别为 15 3～ 198bp和 10 7～ 2 12bp ,其分型结果与PowerPlexTM16系统的分型结果完全一致 ,且用银染法检测的灵敏度显著提高 (由 0 5ng提高到 0 2ng)。PentaD和PentaE基因座在武汉汉族群体分别检出 10个和 2 1个等位基因 ,其基因型频率分布均符合Hardy Weinberg平衡。家系调查证实了其等位基因的传递符合孟德尔遗传规律。两基因座的个体识别能力 (DP)分别为 0 92 62、 0 9860 ,非父排除率 (PE)分别为 0 665 1、 0 83 2 5。结论　新设计引物用于PentaD和PentaE基因座的分型检测准确可靠 ,两基因座多态性程度高 ,在法医学个人识别和亲子鉴定中具有使用价值。     

Population genetics of HPRTB, F13B, and LPL in Pernambuco, Northeast Brazil

One hundred thirty-four unrelated Northeast Brazilian individuals were typed for the HPRTB, F13B, and LPL short tandem repeats (STRs). DNA was amplified by specific primers and identified by silver staining of polyacrylamide gels. The allelic frequencies of these loci were in agreement with Hardy-Weinberg proportions. The most frequent alleles were HPRTB*13, F13B*10, LPL*10. The combined probability of paternity and the discrimination power of these 3 STRs were high, permitting their utilization for forensic science purposes.     

PCR-RFLP在mtDNA多态性分析中的应用

目的探讨PCR-RFLP法在mtDNA多态性分析中的应用价值。方法应用限制酶RsaI和MnlI消化mtDNA D-LOOP区（HVI16106～16297）PCR扩增产物,聚丙烯凝胶电泳进行RFLP分型,对不同PCR-RFLP分型扩增产物进行测序,并对150例辽宁汉族随机个体及30例真三联家系血样进行检验。结果在150例随机个体中,RsaI和MnlI酶切分别发现3和8种表型,DNA测序结果和PAGE分型结果一致,GD值分别为0.107,0.670。联合两种酶切,发现12种表型,GD值为0.708。在30个家系中,母子的RFLP带型完全相同。结论 PCR-RFLP法适合在基层实验室mtDNA分析中应用。     

Discovery and identification of new D13S317 primer binding site mutations

During the course of conventional testing of CODIS standards at the Alabama Department of Forensic Sciences, a sample with a heterozygous null genotype at D13S317 was discovered using the PowerPlex 1.1 kit (Promega, Madison, WI). The loss of both alleles was confirmed when the sample was amplified using PowerPlex 1.2 primers and resulted in a 9, 10 genotype at this locus. To determine the cause of the silent alleles, the ADFS designed D13S317 primers which encompassed the PowerPlex 1.1 D13S317 primer binding sites and sequenced the region. Both alleles showed the presence of two substitutions (T-->A and G-->T) at positions 1 and 5 (5'-->3') of the reverse primer (positions 196 and 200 of the sequence in GenBank accession number ). Since the mutations were identical on both alleles, they may be assumed to be of ancestral origin.     

应用PCR-SSCP技术检测PGM1基因型

目的应用PCR-SSCP技术分型PGM1基因型.方法提取156份武汉地区汉族无关个体的血样DNA,分别扩增PGM1基因外显子4和外显子8的多态性靶DNA,用SSCP分析PCR产物,判断基因型.结果两种PCR产物均检出了两个等位基因、三种基因型,DP值分别为0.5620、0.4405.综合外显子4和8的PCR-SSCP结果,分出8种PGM 1基因型,DP值为0.731 8.应用本法对保存10年的陈旧血痕和精斑PGM1分型成功.结论用PCR-SSCP分型PGM1基因型在法医物证检验中具有实用价值.     

Performance of the SNPforID 52 SNP-plex assay in paternity testing

The performance of a multiplex assay with 52 autosomal single nucleotide polymorphisms (SNPs) developed for human identification was tested on 124 mother–child–father trios. The typical paternity indices (PIs) were 10⁵–10⁶ for the trios and 10³–10⁴ for the child–father duos. Using the SNP profiles from the randomly selected trios and 700 previously typed individuals, a total of 83,096 comparisons between mother, child and an unrelated man were performed. On average, 9–10 mismatches per comparison were detected. Four mismatches were genetic inconsistencies and 5–6 mismatches were opposite homozygosities. In only two of the 83,096 comparisons did an unrelated man match perfectly to a mother–child duo, and in both cases the PI of the true father was much higher than the PI of the unrelated man. The trios were also typed for 15 short tandem repeats (STRs) and seven variable number of tandem repeats (VNTRs). The typical PIs based on 15 STRs or seven VNTRs were 5–50 times higher than the typical PIs based on 52 SNPs. Six mutations in tandem repeats were detected among the randomly selected trios. In contrast, there was not found any mutations in the SNP loci. The results showed that the 52 SNP-plex assay is a very useful alternative to currently used methods in relationship testing. The usefulness of SNP markers with low mutation rates in paternity and immigration casework is discussed.     

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.     

The short tandem repeat locus VWF2 in Intron 40 of the von Willebrand factor gene consists of two polymorphic sub-loci

This study describes the complex nucleotide sequence structure of the TCTA short tandem repeat (STR) locus, VWF2. Eight alleles of VWF2 were observed in a population of 116 unrelated Caucasian individuals. The alleles ranged in size from 150 to 178 base pairs (bp). Sequence analysis of the isolated alleles revealed two polymorphic regions that were named sub-loci VWF2-a and VWF2-b. VWF2-a is located at the 5' end of the conventional locus, whilst VWF2-b is located at the 3' end. The two sub-loci are joined by a 30-nucleotide non-polymorphic sequence which contains two additional TCTA motif repeats. A semi-nested polymerase chain reaction (PCR) was designed to amplify the VWF2-b region in conjunction with the standard VWF2 amplification. This new amplification method enabled a higher level of allele discrimination than could be achieved by assigning alleles according to size. A cohort of 99 unrelated individuals was tested with this method. VWF2-a expressed five different alleles ranging from zero motif repeats to four motif repeats, while VWF2-b alleles ranged from 8 to 14 motif repeats. Allelic configuration based on the VWF2-a and VWF2-b sub-alleles revealed 23 unique configurations out of a possible 31 for the original eight VWF2 alleles. In conclusion, the VWF2 is a highly polymorphic STR locus with potential application for forensic and parentage testing.