The potential contribution of MVR-PCR to paternity probabilities in a case lacking a mother.

Minisatellite variant repeat (MVR) mapping using the polymerase chain reaction (PCR) was applied to a paternity case lacking a mother to evaluate the paternity probability. After three flanking polymorphic sites at each of MS31A and MS32 loci were investigated from the child and alleged father, allele-specific MVR-PCR was performed using genomic DNA. It was confirmed that one allele in the child was identical to that in the alleged father at both loci. Mapped allele codes were compared with allele structures established from population surveys. No perfect matches were found although some motifs were shared with other Japanese alleles. The paternity index and probability of paternity exclusion at these two MVR loci were then estimated, establishing the power of MVR-PCR even in paternity cases lacking a mother.     

The application of minisatellite variant repeat mapping by PCR (MVR-PCR) in a paternity case showing false exclusion due to STR mutation

A boy and a girl with their mother brought a paternity suit against an alleged but deceased father. We tested six conventional genetic markers, the AmpliType PM+ DQA1 and twelve STR loci the children and mother together with the alleged paternal grandparents. We also DNA typed the bloodstain found later in the alleged father's medical record. Only the result at D3S1358 in a nineplex STR system excluded the alleged father from parentage of the boy, whereas all markers were inclusive for the girl. Accordingly, we performed sequence analysis at D3S1358 to confirm the presence of a paternal exclusion or mutation. The sequence analysis indicated that the boy's allele 17 could have originated from either of the alleged father's allele 16 or 18 by a single-step mutation associated with slippage mutation in STR loci. We carried out minisatellite variant repeat mapping by PCR (MVR-PCR) at loci D1S8 (MS32) and D7S21 (MS31A) and mapped allele haplotypes of all individuals except the deceased alleged father. The MVR-PCR analysis showed that the boy has no inconsistency with the relationship between the alleged grandparents, and was very effective at increasing the paternity index (PI) value. We conclude that there is biological relationship between not only the girl but also the boy and the alleged father.     

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。     

Identifiler^TM系统在亲子鉴定中的突变观察和分析

目的观察和分析IdentifilerTM系统15个短串联重复序列(STR)位点在亲子鉴定中的突变现象。方法用IdentifilerTM试剂盒检测2712例亲子鉴定案例。结果在2362例认定亲子关系的案例中,观察到51例中有1个STR位点发生突变。突变的位点包括D8S1179、D21S11、D7S820、CSF1PO、D3S1358、D13S317、D16S539、D2S1338、D19S433、vWA、D18S51、D5S818和FGA。其中以D21S11位点突变率最高(0.369%);突变的等位基因来自父亲36次,来自母亲7次,无法确定9次。结论STR位点突变是较为常见的现象,采用IdentifilerTM系统进行亲子鉴定,遇到1～2个STR位点不符合遗传规律时,有必要增加突变率低、稳定性好的STR位点进行复核。     

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.     

Mutations of short tandem repeat loci in Identifiler system

OBJECTIVE: To explore and analyze the mutations of 15 Short Tandem Repeat (STR) loci using Identifiler system in paternity identification. METHODS: 2712 cases of paternity testing were carried out using Identifiler PCR Amplification Kit. RESULTS: Of the 2362 paternity testing cases, mutations of single locus were observed in 51 cases. The mutation loci included D8S1179, D21S11, D7S820, CSF1PO, D3S1358, D13S317, D16S539, D2S1338, D19S433, vWA, D18S51, D5S818 and FGA, with the D21S11 locus having a highest mutation rate (0.369%). Thirty-six of the STR mutations were from paternal source, 7 from maternal source, and the rest (9) were undeterminable. The mutation rates at D21S11 were highest (0.369%). CONCLUSION: Mutations of STR loci are relatively common in human genome. Therefore, retesting of additional relatively stable STR loci with lower mutation rates is necessary when one or two loci exclusions are encountered in paternity testing.     

亲子鉴定中STR基因座的基因突变分析

目的探讨Identifiler^TM荧光标记复合扩增试剂盒15个STR基因座在亲子鉴定中的基因突变特点。方法应用Identifiler^TM荧光标记复合扩增试剂盒检测676例亲子鉴定案，对其中1～2个突变基因座加做HLA等位基因检测或Y—STR基因座检测。结果在认定亲子关系的676例中，观察1304次减数分裂，Identifiler^TM荧光标记复合扩增试剂盒中的15个基因座确定19例突变，其中D18S51基因座4例，D2S1338基因座3例，D8S1179、D16S539、vWA、D7S820、D13S317基因座各2例，D5S818和TH01基因座各1例，D21S11、FGA、D3S1358、D19S433、TPOX、CSF1P0基因座未见突变；一步突变的17例，二步突变的为1例，四步突变的1例；1个基因座发生突变的18例，2个基因座同时发生基因突变的为1例；突变来自父亲与来自母亲的比例为13：2，4例来源不能确定。结论用Identifiler^TM荧光标记复合扩增试剂盒检测到1—2个基因座发生突变，须增加对其它遗传标记的检测。     

MS31A位点MVR-PCR技术在法医学鉴定中的应用

应用小卫星特异性引物31A、31A -A、31A -G与α -32PdCTP掺入扩增技术对MS31A(位于D7S21位点)进行MVR -PCR分析 ,成功地建立了一套适合于刑事案件中微量血痕、混合斑、毛发、骨组织等样品鉴定的快速、简便、准确的分析技术。灵敏度分析表明 ,该方法能检测出低至1ng的基因组DNA ,具有较高的灵敏性。本技术在40余起强奸、凶杀等疑难案件中应用均获得成功。本研究还利用MVR数据库资料对实际案件中的犯罪嫌疑人成功地进行了筛选、排查以及串并案工作。     

Parentage of Hydatidiform Moles

We were presented with the STR (short tandem repeat) profiles from two separate paternity trios. Each trio consisted of a mother, an alleged father, and products of conception (POC) that contained a hydatidiform mole but no visible fetus. In both cases , antecedent pregnancies had followed alleged sexual assaults. Mole classification and pathogenesis are described in order to explain the analyses and statistical reasoning used in each case. One mole exhibited several loci with two different paternal alleles, indicating it was a dispermic (heterozygous) mole. Maternal decidua contaminated the POC, preventing the identification of paternal obligate alleles (POAs) at some loci. The other mole exhibited only one paternal allele/locus at all loci and no maternal alleles, indicating it was a diandric and diploid (homozygous) mole. In each case, traditional calculations were used to determine paternity indices (PIs) at loci that exhibited one paternal allele/locus. PIs at mole loci with two different paternal alleles/locus were calculated from formulas first used for child chimeras that are always dispermic. Combined paternity indices in both mole cases strongly supported the paternity of each suspect.     

应用MVR-PCR和银染法分析河北汉族人群D1S8基因座DNA结构多态性

研究D1S8基因座重复序列内部的变异,并进行数字编码。应用MVR－PCR和聚丙烯酰胺梯度凝胶电泳银染法对240名河北汉人无关个体进行检测。结果每个个体得到约30个数字编码,未发现任何两无关个体所有编码相同,30个编码完全相同的概率为3．55×10－11。3种重复单位a-型、t-型、o-型出现的频率分别为54.77％、42．54％、2．69％。为小卫星变异重复序列的研究及其在法医实践中的应用提供了一种新方法。     

Identification and characterization of variant alleles at CODIS STR loci

Short tandem repeat (STR) profiles from 32,671 individuals generated by the ABI Profiler Plus and Cofiler systems were screened for variant alleles not represented within manufacturer-provided allelic ladders. A total of 85 distinct variants were identified at 12 of the 13 CODIS loci, most of which involve a truncated tetranucleotide repeat unit. Twelve novel alleles, identified at D3S1358, FGA, D18S51, D5S818, D7S820 and TPOX, were confirmed by nucleotide sequence analysis and include both insertions and deletions involving the repeat units themselves as well as DNA flanking the repeat regions. Population genetic data were collected for all variants and frequencies range from 0.0003 (many single observations) to 0.0042 (D7S820 '10.3' in North American Hispanics). In total, the variant alleles identified in this study are carried by 1.6% of the estimated 1 million individuals tested annually in the U.S. for the purposes of parentage resolution. A paternity case involving a recombination event of paternal origin is presented and demonstrates how variant alleles can significantly strengthen the genetic evidence in troublesome cases. In such instances, increased costs and turnaround time associated with additional testing may be eliminated.     

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.     

Highly polymorphic minisatellite sequences: allele frequencies and mutation rates for five locus-specific probes in a Caucasian population

Six human minisatellite sequences (MS1, MS8, MS29, MS31, MS43, g3) have been subcloned into a stable host/vector system. Allele frequencies at the hypervariable loci detected by five of these probes were determined in a Caucasian population (200 individuals). Mendelian inheritance has been demonstrated in 5 large multi-generation pedigrees. The mutation rate has been determined in 59 families. The highest mutation rate was observed with MS1, as might be predicted from the observed high heterozygosity and in agreement with previous direct measurement of germ line mutation rates. The data presented on allele frequencies and mutation rates provide preliminary data supporting the use of these probes in paternity analysis and forensic investigations.     

Y-chromosome variation in a Norwegian population sample

Y-chromosome DNA profiles are promising tools in population genetics and forensic science. Here we present DNA profiles of 300 unrelated Y-chromosomes of Norwegian origin. The profile is composed of eight short tandem repeats (STRs) and one single nucleotide polymorphism (SNP). In more than 2/3 of the haplotypes the modular structure in the 5' end of the minisatellite locus DYF155S1 was revealed by minisatellite variant repeat PCR (MVR-PCR) These haplotypes were also typed for deletions of fragment 50f2C (DYF155S2). Allele distribution and paternity exclusion parameters are given for each marker. The degree of haplotype diversity and its implication for statistics are evaluated. In the 300 samples 177 different haplotypes were encountered, of which 137 were observed once only. Analysis showed that the main source of variation is within the population. The Fst values were less than 0.015 in general. Haplotype grouping by the SNP demonstrated two haplogroups (Tat/T and Tat/C). Haplogroup Tat/C--found in 5.7% of the present material - is the same haplogroup as encountered in 60% of Finnish males [Am. J. Hum. Genet. 62 (1998) 1171]. Mutation analysis in 150 father/son pairs (a total of 1200 meiotic events) revealed an average mutation frequency of 0.0042 (95% CI 0.0014-0.0097).     

Novel paternity testing by distinguishing parental alleles at a VNTR locus in the differentially methylated region upstream of the human H19 gene

Conventional PCR-based genotyping is useful for forensic testing but cannot be used to determine parental origins of alleles in DNA specimens. Here we describe a novel method of combined conventional genotyping and PIA typing (parentally imprinted allele typing) at a minisatellite region upstream from the H19 locus. The PIA typing uses two sets of primers and DNA digested with methylation-sensitive Hha I enzyme. The first amplification produces only the methylated fragment of paternal H19 allele, and the second detects polymorphism in the minisatellite. Hence, this distinguishes paternal and maternal alleles by difference in the DNA methylation. Furthermore, the polymorphism in this polymorphic locus was examined using 199 unrelated Japanese and 171 unrelated Germans, their polymorphism information content being 0.671 and 0.705, respectively. Feasibility of this typing is demonstrated for six families, and the usefulness is shown by application to paternity testing.     

Characterisation of 12 new alleles in the STR system D18S51

D18S51 alleles 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38 and 40 were detected and sequenced; these new alleles are mistyped with commercial STR kits, causing presumptive null alleles or false exclusions when paternity testing.     

Portuguese population and paternity investigation studies with a multiplex PCR--the AmpFlSTR Profiler Plus

A Portuguese Caucasian population of 146 unrelated individuals was studied. DNA samples were amplified by multiplex PCR for D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S317 and D7S820 using the AmpFlSTR Profiler Plus PCR Amplification Kit (Perkin-Elmer). All loci met Hardy-Weinberg expectations. Forensic statistical parameters were according to those obtained by other authors. Statistical differences were observed concerning three loci when comparing the Portuguese Caucasian population and an Italian Caucasian population, although these differences mainly concern the less frequent alleles. Eighty-three paternity investigation cases were analysed. Exclusions in between three and nine loci were observed in all the 23 exclusion cases obtained. Most of the non-exclusion cases had probability of paternity > 99.9%. Two cases with an isolated genetic incompatibility between the alleged father and the child were detected, which may indicate probable mutation cases. These results demonstrate that the AmpFlSTR Profiler Plus is a suitable multiplex for paternity investigation in the Portuguese population.     

D6S1043和D12S391基因座在亲权鉴定中的应用

目的研究D6S1043和D12S391基因座在亲权关系鉴定案件中的应用价值。方法应用荧光标记复合扩增系统对日常检案中所收集的192名汉族无关个体血样DNA进行PCR扩增,用ABI3100-Avant遗传分析仪对扩增产物进行毛细管电泳,用GeneMapperv3.2软件进行基因分型,统计分析D6S1043和D12S391基因座的多态信息。结果在D6S1043和D12S391基因座分别发现12个等位基因,它们在中国汉族人群中的个体识别能力分别为0.9656和0.9510,二联体非父排除率分别为0.573和0.510,三联体非父排除率分别为0.731和0.679。结论D6S1043和D12S391基因座具有高度多态性,在亲权鉴定中具有重要应用价值。     

Genotyping of five short tandem repeat loci via triplex and duplex PCR

We have developed a triplex PCR method for D3S1359, HumTH01 and HumTPO tetranucleotide loci and a duplex PCR method for HumFES/FPS and HumvWA31A tetranucleotide loci using high resolution polyacrylamide gel electrophoresis and silver staining. The methods were evaluated for paternity testing and individual identification and allele frequencies at these loci are reported for 189–3387 unrelated individuals in the Finnish population. The D3S1359 locus, especially, was found to be a highly informative locus. Seventeen alleles were found in the D3S1359 locus with a highest observed allele frequency of 0.199, a high exclusion power (PE) in paternity testing (0.78) and a high observed heterozygosity (0.89). The combined PE for these five loci was 0.99.     

Paternity testing: blood group systems and DNA analysis by variable number of tandem repeat markers

Two recent paternity cases are reported. In the first case of paternity exclusion, deoxyribonucleic acid (DNA) restriction fragment length polymorphisms (RFLPs) on variable number of tandem repeat (VNTR) loci with multiple alleles were informative, as well as established systems of red blood antigens, red cell enzymes, serum proteins, and human leukocyte antigens. In the second case, in which both the alleged father and the first wife were deceased, the paternal genotype was determined by using genetic markers from the second wife and four children, which then were compared with the paternal alleles of the child in question, the plaintiff in this case. The high probability of paternity (0.999,998,7) made us conclude that the man probably was the actual father. The DNA analysis by VNTR probes appears to be quite valuable in the study of paternity cases.