亲子鉴定中STR位点数选择及其应用价值研究

目的对在亲子鉴定中STR位点数的选择及其鉴定应用价值进行研究。方法将CODIS13个STR位点分为四个观测组,观测对象包括排除亲权的母亲-孩子-假设父亲三人组合102例,以及肯定亲权的母亲-孩子-假设父亲三人组合100例,通过310遗传分析仪对荧光复合扩增产物进行分型检测。结果各STR观察组出现的最低排除指标数与各观察组累积非父排除概率(CPE)值成一定正相关性,CPE值超过99.99%的两个STR观察组其出现的最低排除指标数为三个,同时这两个STR观察组在肯定亲权的案例分析中,其亲子关系概率值(RCP)值都超过了99.99%。结论对于亲子鉴定中的STR位点检测系统,其非父排除指标应为三个以上,其累积非父排除概率(CPE)值达到99.99%时,就可以认为该STR位点检测系统具有了相关的鉴定应用价值。     

Mutation in the STR locus D21S1 1 of father causing allele mismatch in the child

We analyzed a case of paternity dispute with 15 autosomal STR loci and found a mismatch in one of the alleles of the locus D21S11 in the child. The composition of the alleles of this locus in the mother, suspicious father, and child were 29/32, 29/29, and 29/30, respectively. The combined paternity index (2.4 x 10(10)) and paternity probability (0.9999) suggest that the suspicious father is the biological father of the child. Further analysis of 6 Y chromosome STR loci revealed matching of all the Y chromosomal alleles of the child with that of the suspicious father. Since there was a perfect match of all the paternal alleles inherited (15 autosomal and 6 Y chromosomal) in the child with that of the suspicious father except the allele D21S11, it is suggested that this might be a case of mutation. Cloning and sequencing of all the alleles of the locus D21S11 of the suspicious father, mother, and the child helped in determining that the suspicious father contributed the mutated allele.     

13个STR基因座在亲子鉴定案例中的基因突变观察

目的 观察美国 CODIS系统的 13个 STR基因座在532例认定亲子关系的亲子鉴定案中的基因突变情况,探讨STR基因座突变率及突变类型。方法 经“Profiler Plus”及“Cofiler”试剂盒检测的587例亲子鉴定案,对其中有1～2个STR基因座不符合遗传规律者,增加HLA等血型基因和“PowerPlex16~(TM)”试剂盒检测。必要时,还增加Y-STR基因座检测和HLA等位基因测序。结果 认定亲子关系的532例,观察1052次减数分裂,发现17例亲子鉴定中的18次基因突变事件,其中16例1个STR基因座的基因发生突变,1例2个STR基因座的基因发生突变;突变的基因座包括D5S818、D3S1358、D16S539、CSFIPO、D21S11、D13S317、D7S820、vWA、D18S51和FGA,其中以FGA和D18S51基因座的突变率最高(0.29％);18次突变事件,其中来自父亲11次,来自母亲5次,无法确定2次。结论 用美国CODIS系统的STR基因座进行亲子鉴定,在有1～2个基因座不符合遗传规律时,要综合分析,并增加其它的遗传标记进行检测。     

STR复合扩增技术在亲子鉴定中的应用

采用12个荧光标记STR位点复合扩增,进行双亲亲子鉴定和单亲亲子鉴定,取得满意效果.     

海南汉族人群19个STR基因座遗传多态性及其应用

目的建立海南地区汉族人群19个常染色体STR基因座的遗传多态性数据资料,并探讨此19-STR基因座系统在亲子鉴定中的应用。方法对海南汉族462例无血缘关系个体,采用Goldeneye~(TM) 20A系统复合扩增并检测,得到19个STR基因座的遗传数据信息;在283例亲子鉴定案例中,评价19-STR基因座系统的应用。结果 19个STR基因座的基因频率分布均符合Hardy-Weinberg平衡(P0.05),杂合度在0.603~0.914之间,累积个体识别率大于0.999 999 999 999 999,累积三联体非父排除率为0.999 999 994。283例亲子鉴定中,三联体170例,二联体113例;认定案例247例(87.3%),排除案例36例(12.7%);发生等位基因突变案例14例(4.9%),均为一步突变。结论 19个STR基因座中的14个基因座具有高度遗传多态性,19-STR基因座复合扩增分型系统具有较高的非父排除效能,可满足海南地区亲子鉴定的需要,同时应注意亲子鉴定中的基因突变现象。     

亲子鉴定STR突变的考虑

亲子鉴定中常会发生STR（short tandem repeats,短串联重复）突变的情况。突变对亲子关系的判定会造成困扰。对STR突变规律和亲子鉴定中所遇到的STR突变问题、突变的判定、突变下非父排除率和父权指数的计算以及需与突变区分的情形等问题进行综述和讨论。     

Genetic Polymorphisms of four X-STR Loci: DXS6797, DXS6800, HPRTB and GATA172D05 in a Peruvian population sample

The X linked short tandem repeats (STR) markers have proven to be very useful tools for paternity testing when the disputed child is female. The purpose of this study was to describe the genetic polymorphism of four X-chromosomal STR loci (DXS6797, DXS6800, HPRTB and GATA172D05) in a Peruvian population sample and evaluate their efficiency in forensic practice and paternity testing.     

Mutations at 17 STR loci in Chinese population

Knowledge about mutation rates and the mutational process of short-tandem-repeat (STR) or microsatellite loci used in forensic analysis is crucial for the correct interpretation of resulting genetic profiles. We analysed a total of 19,754 samples from 6532 paternity testing cases at 17 STR loci which are commonly applied to forensics. The parenthood in each of these cases was highly validated (probability>99.99%). We identified 178 mutations. Locus-specific mutation rate estimates varied between 7.0 x 10(-5) and 2.2 x 10(-3), and the overall average mutation rate estimate was 8.4 x 10(-4). The observed mutational features for STRs have important consequences for forensic application such as the definition of criterions for exclusion in paternity testing and the interpretation of DNA profiles in identification analysis. In order to enrich the reference data of STRs mutations which are valuable for forensic application, we suggest the establishment of such database and ask the whole forensic community for data contribution including China.     

Significance of additional RFLP single locus probes analysis after STR based determination of sibship

Autosomal STR typing alone seems to be no sufficient tool for resolving deficiency cases (e.g. cases of questioned paternity or half-sibships). Therefore, we investigated whether the additional analysis of RFLP single locus probes can improve the solution of such complicated kinship cases. We analyzed 207 children and men from 101 families using the AmpFlSTRIdentifiler multiplex PCR kit and three RFLP single locus probes. A comparison between each child and all unrelated men resulted in 11,023 man / child pairs. Less than three excluding STRs were found in 125 child / unrelated man pairs (1.13%). Additional analysis of RFLP results reduced the number of ambiguous cases to 35. Half-sibling pairs were simulated using STR results from 20 cases with high paternity probabilities (group 1) and relatively low paternity probabilities (group 2). Using a commercially available computer program we calculated probabilities for 778 half-sibling pairs. In 35 pairs (4.49%) half-sibling probabilities over 90.0% could be calculated. Additional investigation of RFLP single locus probes did not lead to a more reliable evaluation of these results. The combined investigation of autosomal STRs and RFLP single locus probes can satisfactorily solve deficient paternities but does not contribute to the solution of questioned half-sibships.     

Allele distribution of three X-chromosome STR loci in an antioquian population sample

The X-linked short tandem repeats (STR) markers have proven to be very useful tools for paternity testing when the disputed child is female. The aim of this study was to describe the polymorphism of three X-chromosomal STR loci (DXS6797, DXS6800 and HPRTB) in an Antioquian (Colombian) population sample. PCR products were separated in 4% acrylamide-bis-acrylamide denaturing gels followed by silver staining. Allele size determination and genotyping were performed according to recommendations of the DNA Commission of the International Society of Forensic Genetic using the allelic ladder manufactured at home and based on DNA controls including K562 and 9947A (Promega). Gene frequencies were calculated using ARLEQUIN version 3.11. Population genetic data were obtained by analyzing 127-400 unrelated males and 135 unrelated females from Antioquian (Colombian) population. Distribution of the allele frequencies of these systems for Antioquia population is similar to the European populations.     

西安汉族X染色体上6个STR位点的遗传多态性

目的调查西安汉族人群6个位于X染色体上的短串联重复序列:DXS8378、DXS7132、DXS6789、DXS101、HPRTB和DXS7423的基因及基因型频率分布。方法应用PCR和变性聚丙烯酰胺凝胶电泳及银染技术检测结果。结果在120例女性无关个体中,DXS8378、DXS7132、DXS6789、DXS101、HPRTB和DXS7423分别检出5、6、11、10、8和4个等位基因;分别检出10、17、29、32、22和7种基因型;此6个位点女性的基因型频率分布均符合Hardy-Weinberg平衡。结论此6个X染色体STR位点均有较高的个体识别率,在个体识别和女孩的亲权鉴定中有应用价值,对疾病相关研究有实际意义。     

Allele frequencies for 15 autosomal STR loci and admixture estimates in Puerto Rican Americans

Allelic frequencies of 15 short tandem repeats (STR) markers (CSF1PO, FGA, THO1, TPOX, VWA, D3S11358, D5S818, D7S820, D8S1179, D13S317, D16S539, D18S51, D21S11, D19S433 and D2S1338) were determined using the AmpFl STR Identifiler PCR Amplification Kit in Puerto Rican American individuals (N=205) from Massachusetts. The FGA, D18S51 and D2S1338 loci had a high power of discrimination (PD) with values of 0.967, 0.965 and 0.961, respectively. Significant deviations from the Hardy-Weinberg (HW) equilibrium were not detected. An important genetic contribution of Caucasian European (76.4%) was detected in Puerto Rican Americans. However, comparative analysis between Puerto Rican American and other neighboring populations from United States mainly with African and Caucasian Americans, revealed significant differences in the distribution of STR markers. Our results are important for future comparative genetic studies of different American ethnic groups, in particular a cultural group called Hispanic-Americans and should be helpful for forensic and paternity testing.     

Validation of the STR DXS7424 and the linkage situation on the X-chromosome

X-linked microsatellite markers have proven to be powerful tools for parentage testing, mainly in deficiency paternity cases when the disputed child is female. However, only a small number of X-linked short tandem repeats (STRs) have been comprehensively described for forensic applications to date.We present sequence and population genetic data of the DXS7424 STR (GDB-G00-577-633) which is a trinucleotide repeat polymorphism representing 12 alleles of 147-180 bp in length. DXS7424 is located at Xq22 and closely linked to DXS101, corresponding to a genetic localisation of 104.9-121 cM from Xp-tel.PCR fragment length measurements and sequencing were carried out using the automatic gene analyser ABI 310 (Applied Biosystems).The population of 764 unrelated Germans checked for this STR exhibited the following features: polymorphism information content (PIC) = 0.780; heterozygosity (Het) = 0.843; mean exclusion chance (MEC = 0.766. Kinship tests revealed a typical X-linked inheritance. In 300 meioses under investigation, mutations were not found. Significant deviations from the Hardy-Weinberg equilibrium (HWE) were not established.Linkage studies confirmed closely linkage to DXS101. Additional we found linkage disequilibrium between DXS7424 and DXS101. This requires to use the established haplotype frequencies in kinship testing.     

Two loci ‘exclusion’ of true paternity is due to genetic disorder in a child

We describe a paternity case with three genetic incompatibilities between a three-year-old boy and his putative father.STR analysis of 2 out of 25 markers revealed the absence of paternal alleles and presence of two maternal alleles at D2S441 and D2S1338 loci in the child. The rest 23 STR markers served to confirm paternity. In addition, we analyzed Y-STRs and determined the same haplotype in the child and his putative father.With massive parallel sequencing on HID Ion GeneStudio S5 System using Precision ID GlobalFiler NGS STR Panel v2 (Applied Biosystems) we confirmed the presence of two alleles of maternal origin at D2S441, D2S1338 loci and identified two maternal alleles at additional locus D2S1776 located on chromosome 2 in the child.Finally, we confirm paternity. Three loci ‘exclusion’ was due to maternal uniparental disomy of chromosome 2 in the child.     

AGCU免提取STR荧光检测试剂盒的验证

目的考察AGCU免提取STR荧光检测试剂盒．对保存在滤纸片或FTA卡上血液样本的直接扩增检测情况。方法使用人GCU免提取STR荧光检测试剂盒,对未经提取的滤纸片血液样本、FTA卡血液样本675份进行直接扩增和18个基因座的DNA分型,并对结果的可靠性进行研究。结果18个基因座检测结果与PP16和ID试剂盒分型结果一致,2000年数据库样本成功率92．3％,2001年数据库样本成功率92．6％,2004以后年数据样本及案件样本、亲子鉴定样本成功率在99％以上。结论AGCU试剂盒可以成功地对滤纸片、FTA卡样本的18个STR基因座进行直接扩增检测,检验结果稳定,分型准确。     

DNA数据库9个STR基因座比中认定亲权的可靠性分析

目的探讨Profiler plus试剂盒9个常染色体STR基因座用于DNA数据库中双亲亲缘关系比中结果认定亲权的可靠性。方法在DNA数据库中搜集无关个体与已知母子（或父子）在9个STR基因座不排除亲缘关系的比中记录54例，组成54例假定的三联体家庭，计算其PI值与RCP值；应用Identifiler试剂盒加做到15个常染色体STR基因座，观察其排除情况。结果在54例假定三联体中PI值最低为178．598597（RCP=99．443203％），最高为97318．085812（RCP=99．998972％）。加做到15个STR基因座后，54例假定三联体中每个三联体至少出现2个基因座排除，最多5个基因座出现排除的现象，平均排除基因座数为3．52个。结论Profilerplus试剂盒9个STR基因座用于亲缘关系鉴定可能出现错误结论；单纯利用RCP值来认定亲缘关系是不安全的；建议应用16个或更多的基因座建设DNA数据库和进行亲缘关系判定。     

Genetic data for the 13 CODIS STR loci in Singapore Chinese

Allele frequencies for the 13 CODIS STR loci included in the AmpFISTR Profiler Plus and AmpFISTR Cofiler kits (Applied Biosystems, Foster City, USA) were determined in a sample of 209 unrelated Chinese in Singapore. The combined random match probability for the 13 loci is about 6.6 x10(-15) and the overall probability of excluding paternity is 0.9999899. The results demonstrate that the loci are useful for forensic human identification and parentage testing for the Chinese population in Singapore.     

MiniFiler及Yfiler试剂盒无创产前亲子鉴定的可能性探究

目的采用Mini Filer~(TM)及YFiler~(TM)试剂盒对孕妇血浆进行STR分型,评估上述试剂盒进行无创产前亲子鉴定的可行性。方法采用Mini Filer~(TM)及YFiler~(TM)试剂盒,对2例成人男性的全血及血浆进行STR分型,评估血浆检材的分型准确率及适用性;对8组已知亲子关系的孕妇家系(4组非父,4组亲父,均为男胎样本)采用Mini Filer~(TM)及YFiler~(TM)试剂盒进行STR分型,对STR分型图谱直接观察,总结归纳孕妇血浆STR图谱的特征,探讨进行无创产前亲子鉴定的可行性。结果血浆检材的STR分型结果与全血STR分型结果 100%一致,且等位基因峰高接近,表明血浆是一类可以进行STR分型的检材;观察8组孕妇血浆检材的STR分型图谱,可获得2~5个可用(含胎儿STR信息)Mini-STR位点,1~8个可用Y-STR位点,且在位点充足的情况下(6个),肯定父权家系可计算累计父权指数达192 653,否定父权家系中有3~7个位点支持否定父权。结论采用Mini Filer~(TM)及Yfiler~(TM)试剂盒对孕妇血浆进行STR分型,存在进行无创产前亲子鉴定的可能性。     

常染色体STR突变基因座父权指数计算

目的概括归纳常染色体STR突变基因座的父权指数计算方法,以在实际检案中应用推广。方法根据目前对常染色体STR基因座突变的认识,用经验递减模型从基因座突变率计算等位基因突变率,分别推导在标准三联体和二联体亲子鉴定中STR突变基因座的父权指数计算式,并举例进行演算。结果总结了在标准三联体鉴定中,只允许假设父突变和既允许假设父也允许母发生突变时,以及二联体鉴定时X和Y的计算式。结论STR基因座发生突变时计算得的父权指数明显低于未发生突变时,提示要检测更多的遗传标记才能使累积父权指数达到认定亲权关系的标准。     

Mutation rates at 14 STR loci in the population from Pernambuco, Northeast Brazil

Definition about mutation rates of short tandem repeats (STRs) loci used in forensic analysis are useful for the correct interpretation of resulting genetic profiles and the definition of criterions for exclusion in paternity testing. Germline mutation of 14 STR loci was studied for 54,105 parent–child allelic transfers from 2575 paternity testing cases carried out during 2000–2007 from the Pernambuco State, Northeast Brazil. The parenthood in each of these cases was highly validated (probability > 99.99%). We identified 43 mutations at 12 loci. Locus-specific mutation rate estimates varied between 2 × 10⁻⁴ and 2 × 10⁻³, and the overall mutation rate estimate was 8 × 10⁻⁴. Mutation events in the male germline were more frequent than in the female germline. The majority of the mutations could be explained by losses or gains of one repeat unit and there was no evidence for selection between insertion or deletion changes. Our data were compared with those of Portuguese and North-American populations for CSF1PO, D18S51, D21S11, D7S820, TH01, TPOX and demonstrated, despite the great difference in the size of the sample, that mutation rates of STR loci in a mixed population do not differ from that encountered in different populations.