The problem of single parent/child paternity analysis--practical results involving 336 children and 348 unrelated men

In a certain amount of paternity investigations, only DNA from child and alleged father is analyzed, thus increasing the possibility of false paternity inclusions. The aim of this study was to determine how many wrong paternity inclusions could be detected in a rather small geographical area comparing empirical results from 336 children and 348 men (13-15 STRs were investigated per person). This comparison between each child and all unrelated men (i.e. all putative fathers from the other cases) with an especially designed computer program resulted in 116,004 man/child pairs. Less than three excluding STRs were found in 1666 child/unrelated man pairs (1.44% of the comparisons). At least one unrelated man with only two or less STR mismatches could be determined for 322 children (95.8% of all investigated children). In 26 comparisons no STR mismatches between a child and an unrelated man were detected, thus at least one and up to three "second father(s)" under 350 men could be found for 23 children, if the mother is excluded. Paternity probabilities between 95.475% and 99.996% were calculated. Our results underline the difficulties in motherless paternity cases using only STR analysis and advise great precaution in assigning verbal predicates such as "paternity proven" in those investigations.     

论诉讼中的亲子鉴定

近年来,涉及亲子鉴定的亲子关系诉讼案件越来越多,而我国在亲子鉴定方面的法律规范却几乎处于空白状态．给法院在审理亲子鉴定案件时如何正确适用法律增加了难度。从审判实践出发,依据现有的零星的法律规定,对亲子鉴定的提起程序、亲子鉴定结论的证据效力及其审查判断等进行分析探讨尤为必要。     

A new 39-plex analysis method for SNPs including 15 blood group loci

A novel 39-plex typing system for single nucleotide polymorphisms (SNPs) has been developed. This multiplex approach has the advantage of being able to type 38 autosomal SNPs and one sex-discriminating base exchange site on the X and Y chromosomes rapidly and simultaneously. The SNP loci on the autosomes, which we examined, contain 15 loci distributed on blood type genes: three on RhCE, two each on Km and Gc, and one each on Duffy, AcP1, Tf, MN, GPT, EsD, PI, and Kidd genes. Thirty-seven genomic DNA fragments containing a total of 38 SNPs and one sex-discriminating site were amplified in one multiplex PCR reaction. Following the reaction, single nucleotide primer extension reaction was performed by dividing these SNP loci into five groups. The SNP type of each of the 39 loci was determined at one time by capillary electrophoresis using the newly designed multi-injection method. The combined PD (power of discrimination) of this typing system was (1-1.1) x 10(-14), and the MEC (mean exclusion chance) was 0.9990. We applied this system to forensic cases, including 16 paternity testing cases (13 non-exclusion and three exclusion cases) and one personal identification case. For the paternity testing cases, the highest Essen-M?ller's W-value was 0.9999995. The pM (matching probability) of the personal identification case was 2.22 x 10(-17). These data showed that this system was an excellent tool for use in forensic cases of paternity testing and personal identification.     

Further evidence of a silent plasminogen (PLG) allele in two paternity cases

Routine paternity testing has yielded two different cases of an apparent inverse homozygosity in the plasminogen (PLG) system. In one case, the child presented the phenotype PLG A and his putative father the type PLG B. The alleged father could not be excluded from the paternity in 25 additional blood group marker systems (biostatistical probability of paternity W greater than 99.75%). In the other case an incompatibility was found in a mother- child pair. Analysis of PLG was carried out by isoelectric focusing on neuraminidase-treated sera. In both cases the immunologic and functional detection showed weaker banding pattern of the affected PLG types. The assumption of a silent allele in the PLG system was confirmed by quantitative investigations. The allele frequency of PLG*Q0 in the South German population was estimated to be 0.0013. In the same sample the variant PLG A3 has been shown to be polymorphic.     

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.     

ISFG: Recommendations on biostatistics in paternity testing

The Paternity Testing Commission (PTC) of the International Society for Forensic Genetics has taken up the task of establishing the biostatistical recommendations in accordance with the ISO 17025 standards and a previous set of ISFG recommendations specific to the genetic investigations in paternity cases. In the initial set, the PTC recommended that biostatistical evaluations of paternity are based on a likelihood ratio principle – yielding the paternity index, PI. Here, we have made five supplementary biostatistical recommendations. The first recommendation clarifies and defines basic concepts of genetic hypotheses and calculation concerns needed to produce valid PIs. The second and third recommendations address issues associated with population genetics (allele probabilities, Y-chromosome markers, mtDNA, and population substructuring) and special circumstances (deficiency/reconstruction and immigration cases), respectively. The fourth recommendation considers strategies regarding genetic evidence against paternity. The fifth recommendation covers necessary documentation, reporting details and assumptions underlying calculations. The PTC strongly suggests that these recommendations should be adopted by all laboratories involved in paternity testing as the basis for their biostatistical analysis.     

Identifiler^TM系统在亲子鉴定中的应用评估

目的评估Identifiler^TM系统15个短串联重复序列（STR）基因座在亲子鉴定中的检验能力。方法用Identifiler^TM系统检测3277例亲子鉴定案例,观测和分析该系统在亲子鉴定中的排除能力及基因突变率。结果累积非父排除率为0．999998827,累积个体识别能力为0．99999999999999998。3277例亲子鉴定中有2863例认定亲权关系,347例排除亲权关系;观察到65例中有1个STR基因座发生突变,2例中有2个STR基因座发生突变。结论Identifiler^TM体系应用于亲子鉴定是高效、可靠的。     

The forensic and investigative significance of reverse paternity testing with absent maternal sample

The authors are involved in the extraction of DNA material from calcified tissues, oftentimes teeth, and analysis of such material to assist the investigative process, frequently by confirming the identity of the victim. Biologic or molecular techniques for the purposes of human identification have evolved to allow increasingly discriminating tests for use in criminal and noncriminal death investigations, as well as paternity disputes. The goal of such tests is to either include 2 samples (ie, they are from the same person, or in the case of paternity, they are from related individuals) or exclude 2 samples (ie, they are from different people or from unrelated individuals). Regardless of the system used and when data error has been eliminated, an exclusionary conclusion is irrefutable. The probability of excluding the falsely accused has steadily increased over the years as new methods are developed. Conventional ABO blood typing, for example, has a probability of exclusion (PE) of only 17%. This value increases to 53% with the inclusion of the Rh and MN systems. Additional serological markers can provide a probability of exclusion of greater than 99%. Today, the current method of choice for human identification is the polymerase chain reaction for the amplification of short tandem repeat (STR) multiplexes. This paper discusses the implications of nonpaternity in reverse paternity testing when only paternal DNA is available.     

单亲亲子鉴定及其法律问题思考--附275例单亲鉴定分析

目的探讨单亲鉴定及其有关的法律及社会问题. 方法对1998年1月至2002年12月275例单亲鉴定进行回顾分析,对案例的数量、来源、鉴定事由、鉴定结论等作统计分析. 结果单亲鉴定近3年明显增多,占亲子鉴定总数的三成.案例来源以自诉为主,占95.27%.鉴定事由中,怀疑妻子有婚外性关系为主 ,占88.36%.275例单亲鉴定中,排除亲生关系39例,占14.18%.结果表明,非婚生子女只占少数. 结论自诉单亲鉴定存在法律盲区,但在维护家庭稳定具有一定作用.受理单亲鉴定宜取慎重态度,有关的社会及法律问题需要解决.     

Paternity analysis in deficiency cases with related putative fathers: simulation of a deficiency analysis in 27 families

During the last few years, the number of privately ordered paternity investigations has increased considerably. Probably due to financial reasons in more and more cases only the putative father and the child are investigated. Additionally, very often only one method, such as STR analysis, is employed. This raises the question whether such a reduced analysis leads to reliable and clear results when investigating cases with related putative fathers. We investigated 165 individuals from 27 families using the AmpFlSTRIdentifiler multiplex PCR and calculated the paternity probabilities of the children to their biological fathers, uncles, grand fathers and other relatives. In more than 30% less than three exclusions between child and relative were detected. In five cases no exclusions were found between child and uncle, always leading to paternity probabilities >99.9%. These results show that the calculation of high probabilities (>99.9%) does not necessarily lead to the accurate conclusion of fatherhood. In many of our cases misleadingly the brother of the real father or another close relative would have been declared to be the biological father.     

SNPs in paternity investigation: The simple future

Based on the 52 SNP-plex developed by the SNPforID Consortium, we designed two 10-plex to study single nucleotide polymorphisms (SNPs) for human identification and to establish its usefulness in paternity casework. This 20 autosomal SNP set was studied in 56 paternity investigation cases from South Portuguese resident population, also analyzed with 17 Short Tandem Repeats (STRs). Results obtained with both methodologies were consistent with each other, except for one case where the alleged father could not be excluded by SNPs. No mutation was found in the SNP loci, whereas a mismatch in STRs was detected. The use of SNPs as a complement to the analysis of autosomal STRs in paternity casework can result in paternity index and paternity probability values equivalent or higher than those obtained with more STR loci, but with lower costs. This study shows that instead of using additional STR loci, the analysis of 20 autosomal SNPs, as a complement technique to standard methodologies, is an appealing alternative in paternity investigation cases.     

Combination of DNA-based and conventional methods to detect human leukocyte antigen polymorphism and its use for paternity testing

In cases of disputed paternity, the scientific goal is to promote either the exclusion of a falsely accused man or the affiliation of the alleged father. Until now, in addition to anthropologic characteristics, the determination of genetic markers included human leukocyte antigen gene variants; erythrocyte antigens and serum proteins were used for that reason. Recombinant DNA techniques provided a new set of highly variable genetic markers based on DNA nucleotide sequence polymorphism. From the practical standpoint, the application of these techniques to paternity testing provides greater versatility than do conventional genetic marker systems. The use of methods to detect the polymorphism of human leukocyte antigen loci significantly increases the chance of validation of ambiguous results in paternity testing. The outcome of 2384 paternity cases investigated by serologic and/or DNA-based human leukocyte antigen typing was statistically analyzed. Different cases solved by DNA typing are presented involving cases with one or two accused men, exclusions and nonexclusions, and tests of the paternity of a deceased man. The results provide evidence for the advantage of the combined application of various techniques in forensic diagnostics and emphasizes the outstanding possibilities of DNA-based assays. Representative examples demonstrate the strength of combined techniques in paternity testing.     

Laboratory evidence of unsuspected parental consanguinity among cases of disputed paternity

A search was conducted to find evidence of possible incestuous unions between the biologic parents of children involved in 2500 paternity cases. Suspicion was raised when either (1) a mother and her child possessed identical HLA phenotypes, or (2) the child appeared to be possibly homozygous for one maternal haplotype (i.e., one of the child's HLA haplotypes was a blank). These mother-child HLA-haplotype dualisms (MHDs) occurred in 5% of all cases. Frequency of exclusion of the accused men in cases demonstrating MHD, was compared with the remaining paternity cases.No significant difference was found in overall exclusion rates between MHD cases and controls when exclusion produced by HLA and red cell antigen systems were observed. However, there was a greater rate of exclusion in MHD cases when comparing exclusions produced by red cell antigen systems regardless of whether HLA tests excluded paternity (p < 0.025). MHD cases involving teenaged mothers differed from control cases in frequency of exclusion of paternity only on the basis of red cell antigen phenotyping (p < 0.005).The HLA system's usefulness in paternity testing is diminished when there is MHD; multiple, independently-inherited systems are relatively more useful in these circumstances.The search method detects only half of potential incest cases; proof of incest requires more extensive testing for homozygosity among other polymorphisms. Since calculations of likelihood of paternity are inappropriate in cases involving close consanguinity, detection and follow up studies are important.Data suggest that one-fifth of MHD cases may involve first degree consanguinity and that the incest rate among paternity cases may be as high as 2%.     

PowerPlex~(TM) 16体系在亲子鉴定中的应用评估

目的 评估PowerPlexTM16体系在亲子鉴定中的检验能力。方法 以633例亲子鉴定案例为基础,调查PowerPlexTM16体系15个STR基因座的群体遗传学数据资料,并对该体系在亲子鉴定中的排除能力及遗传稳定性进行评估。结果 879名无关个体共检出197个等位基因,739种基因型,累计个体识别力为1×10-30,累计非父排除率为0.999999999999987。633例亲子鉴定案件中有95例确定为排除亲权,平均排除指标为6个。18例表现出1个STR基因座突变的现象,1例表现出2个STR基因座突变的现象。结论 PowerPlexTM16体系应用于亲子鉴定是高效、可靠的。     

Wrongfully Convicted: How the Dutch Deal with the Revision of Their “Miscarriages of Justice”

During most of the twentieth century the very existence of judicial errors was considered an awkward subject in the Dutch legal system. This article considers the change of attitude in recent years. In previous years there was a remarkable self-confidence within the criminal justice system (and in most of the scholarly writings) in doing things the ‘right way.’ After a few warnings from (only partly legally trained) scholars, who became interested in the functioning of the system, and moreover, after a few clear and undeniable cases of judicial error, there was a volte-face in the general feeling amongst both the public and the profession. It is the opinion of the authors that this shift in opinion is historically important. This article therefore intends to draw a picture of the current state of affairs in The Netherlands.     

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.     

Genomic "dactyloscopy" in the expertise of disputed paternity and the determination of biological relationship

Genome "dactyloscopy" (DNA fingerprinting) is a principally new way of personal identification based on analysis of human genetic material (DNA); the difference in DNA structure of different subjects is the scientific basis of this method. This ensures opportunity to estimate biological relationship of persons positively. The authors were the first to demonstrate using certain expert material the adequacy and potentials of DNA fingerprinting by M 13 probe for medicolegal expert practice in most complicated cases of relationship determination requiring positive identification of paternity and maternity.     

母血浆中胎儿游离核酸与无创性产前亲子鉴定

近年来,涉及胎儿亲权鉴定的案例逐渐增多。传统胎儿产前亲权鉴定常需有创性取样,故存在一定的风险。母血浆中胎儿游离核酸的发现,给无创性产前亲权鉴定带来了新的契机。本文主要就母血浆中胎儿游离核酸及其在无创性产前亲权鉴定中的应用价值和前景进行简要介绍。     

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。     

Paternity Testing Commission of the International Society of Forensic Genetics: recommendations on genetic investigations in paternity cases

The International Society for Forensic Genetics (ISFG) has established a Paternity Testing Commission (PTC) with the purpose of formulating international recommendations concerning genetic investigations in paternity testing. The PTC recommends that paternity testing be performed in accordance with the ISO 17025 standards. The ISO 17025 standards are general standards for testing laboratories and the PTC offers explanations and recommendations concerning selected areas of special importance to paternity testing.