Paternity Testing Cases Research Articles

Mutation analysis of 24 short tandem repeats in Chinese Han population

Germline mutations of 24 short tandem repeat (STR) loci (TPOX, D3S1358, FGA, D5S818, CSF1PO, D7S820, D8S1179, TH01, vWA, D13S317, Penta E, D16S539, D18S51, Penta D, D21S11, D2S1772, D6S1043, D7S3048, D8S1132, D11S2368, D12S391, D13S325, D18S1364, and GATA198B05) were studied for 6,441 parent-child meioses taken from the paternity testing cases in Chinese Han population. In total, 195 mutations were identified at 22 of the 24 loci. Among them, 189 (96.92%) mutations were one step, five mutations (2.56%) were two step, and one mutation (0.51%) was three step. No mutation was found at the TH01 and TPOX loci. The overall mutation rate estimated was 0.0013 (95% CI 0.0011-0.0015), and the locus-specific mutation rate estimated ranged from 0 to 0.0034. There was a bias in the STR mutations that repeat gains were more common than losses (∼1.7:1). Mutation events in the male germline were more frequent than in the female germline (∼4.3:1). Furthermore, loci with a larger heterozygosity tended to have a higher mutation rate. Mutation in short alleles was biased towards expansion, whereas mutation in long alleles favored contraction. The long alleles have a higher allelic mutational probability than short alleles.

A loophole in Spanish law and unsolved ethical issues in paternity testing

Article 18 of the current Spanish Constitution (which came into force in 1978) defends all citizens’ right to privacy. Accordingly, the new Code of Ethics of the Spanish Medical Association includes several articles concerning studies conducted on genetic information and the acceptance of such studies by all individuals involved. As a result, a serious problem arises in paternity testing cases when investigating an alleged father–child relationship when the biological mother has not given consent for access to be gained to her genetic information. When it comes to the laboratory investigating these cases, the problem of lack of permission from a parent is greater when the child is a minor or has a mental or psychological disability because current Spanish legislation calls for informed consent to be given by legal representatives. The law does not specify what happens when one parent (for instance, the putative father) gives consent while the other (the mother) does not. There are currently no Spanish judicial records addressing the issue. Depending on the spirit of the law, it is logical to understand both how a team from a forensic genetics laboratory are likely to be sued for performing a biological paternity test without the mother's permission and how indeed the lawyer could win the case. The purpose of this study is to provide legal solutions in order to avoid potential problems arising with regard to legislation.

The Forensic Genetics Laboratory of the University of Barcelona: The evolution of paternity testing cases over the past 35 years

Biological paternity research in Catalonia (north-eastern Spain) began in 1976 when Dr. Castillo, Dr. Gelabert and Dr. Huguet studied the first case at the Department of Forensic and Legal Medicine of the University of Barcelona in cooperation with the Haemostasis and Hemotherapy Service and the Blood Bank of the Hospital Clínic in Barcelona. In the knowledge that each human is genetically unique as a result of genetic polymorphism, blood group antigen typing and other immunological techniques including human histocompatibility leukocyte antigen (HLA) typing became widely used for paternity testing and forensic science application until the end of the 1970s. However, biological tests were not accepted by the courts in Spain until 1981 when the Civil Code was reformed. With the support of Dr. Carracedo from the University of Santiago, in 1982 Dr. Huguet and Dr. Gené, who are still actively researching, set up the Haemogenetic Forensic Laboratory at the University of Barcelona and this area of the Legal Medicine Unit was thus consolidated. It was the first Forensic Genetics Laboratory in Catalonia. The aim of this study is to conduct a retrospective analysis of paternity testing cases over the past 35 years. We report on the social and legal development of the cases analysed, grouped into different periods of time. The results on paternity and non-paternity claims were studied included exclusion and non-exclusion rates. Biomathematical performance values were reported for each methodology stage (number of exclusions, average paternity probability values, population index, etc.).

Mutation analysis of 24 autosomal STR loci using in paternity testing

To obtain the knowledge about the locus-specific mutation rate and characteristics of 24 autosomal STR loci, fifteen STR loci ( D31358 et al.) were typed with the PowerPlex ® 16 system (Promega, USA) for 11175 DNA-confirmed paternity testing cases (8059 trios, 1978 father-child duos and 1138 mother-child duos), and nine STR loci (D2S1772 et al.) were typed with the STRtyper ®-10F/G system (Condon, China) for 4046 DNA-confirmed paternity testing cases (2115 trios and 1227 father-child duos and 704 mother-child duos). A total of 343,959 meiotic transfers were analyzed and 488 mutations were identified. The overall average mutation rate was estimated as 0.00142 and the estimated locus-specific mutation rate varied between 0.00010 and 0.00422. Mostly only one mutation occurred in a case, while there were 20 cases with double mutations and 2 cases with triple mutations investigated with 24 STR loci genotyping. One-step mutation was accounted for 98.16% of total mutations. The ratio of paternal versus maternal mutation was 3.66:1. Except for those two cases with triple mutations, the combined paternity index (CPI) value of 24 STR loci was greater than 10,000 when calculated including the mutation loci.

A fast and effective method to perform paternity testing for Wolong giant pandas

Captive populations provide a precious genetic resource for endangered animals and a source of individuals for reintroduction to depleted habitats. Therefore, accuracy in determining paternity is of vital importance for managing captive populations and in selecting representative individuals of known genetic characteristics for release. In this study, we established a fast and effective method to conduct paternity testing for captive giant pandas in the Wolong population. This technique uses two highly polymorphic microsatellites initially, subsequent use of five less polymorphic markers and then paternity exclusion testing carried out using the giant panda paternity exclusion program we have developed. Our results revealed that (1) both sets of markers successfully identified the real fathers in 25 cases of paternity testing and (2) the success rate of paternity exclusion varied with the degree of polymorphism of the markers used. Subsequently, we conducted correlation analysis between the success rates of paternity identification with these markers, parameters of genetic diversity and tests of neutrality. We found that the paternity exclusion power of microsatellites was significantly correlated with the number of alleles (Na), expected heterozygosity (HE) and observed homozygosity statistic (FO) (all P < 0.05). From this, we developed a new variable, Na×HE/FO, showing a highly significant positive correlation with the resolution power of microsatellites (P = 0.001). Moreover, the first two highly polymorphic loci gave a 100% success rate of excluding non-paternal males because they yielded higher values of Na×HE/FO than the other five less polymorphic markers. Thus, the Na×HE/FO parameter appears suitable to serve as a criterion for selecting microsatellite markers, which could be used for high-resolution molecular techniques of paternity determination among a range of captive animals besides giant pandas.

Genetic polymorphisms of nine non-DNA combined index system short tandem repeat loci in Hebei Han population and application in paternity testing

To investigate the polymorphisms of 9 non-DNA combined index system (CODIS) short tandem repeats (STRs), i.e., D7S3048, D8S1132, D11S2368, D2S1772, D6S1043, D13S325, D12S391, GATA198B05, D18S1364 in Hebei Han population, and evaluate the usage of them in paternity testing. One hundred and forty-seven unrelated healthy individuals from the Han population of Hebei province were genotyped using STRtyper10G kit including 9 STR loci on ABI 3130 Genetic Analyzer. Hardy-Weinberg equilibrium and population genetic parameters were calculated. Fourteen cases of motherless paternity testing and 2 cases of standard trios with mutation in 1 locus were detected using STRtyper10G. (1) Ninety-nine alleles and 336 genotypes were observed in the 9 STR loci in the population. The cumulative discrimination power(DP) was higher than 0.999,999,999. The cumulative probability of exclusion (PE) for trios and duos were 0.999,974 and 0.998,759 respectively. Departure from Hardy-Weinberg equilibrium was not observed in any of the 9 loci. (2) The combined paternity index (PI) of the 14 cases of motherless paternity testing ranged from 10³-10⁶ for 15 STR loci in ID, whereas it reached 10⁵-10⁹ for 22 independent STR loci included in ID and STRtyper 10G. Possible mutation in FGA and vWA was observed in 2 cases of trios, and the combined PI was 5945 and 1840 respectively for 15 STR loci in ID. Adding STRtyper 10G to detect these 2 cases, the combined PI reached 2.76 × 10⁷ and 4.88 × 10⁷ respectively. The genetic polymorphism of the 9 non-CODIS STR loci included in STRtyper 10G was quite high in Chinese Hebei Han population, indicating the 9 STR loci are valuable as complement markers for ID and PP16 kit in motherless paternity testing, paternity testing with mutation and other kinds of complicated paternity testing.

Genetic polymorphisms of 17 short tandem repeat loci on Y chromosome in central Croatian population

In forensic casework, Y-chromosome short tandem repeat (STR) haplotyping is used in human identification, paternity testing and sexual assault cases where Y-STRs provide a male-specific DNA profile. The aim of this study was to describe the genetic structure of Y chromosome in a central Croatian population. We carried out a statistical analysis of the data from previously performed genetic analyses collected during routine forensic work by the Forensic Science Centre "Ivan Vučetić". A total of 220 unrelated healthy men from central Croatia were selected for the purpose of this study. Genomic DNA was extracted using a Chelex procedure from FTA(®) cards. Y-chromosomal STRs were determined using the AmpFISTR Yfiler PCR amplification kit. The haplotype frequencies were determined by direct counting and analyzed using Arlequin 3.1 and analysis of molecular variance calculated with the Y chromosome haplotype reference database online analysis tool. A total of 212 haplotypes were identified, 204 of which were unique. Total haplotype diversity was 0.993. Locus diversity varied from 0.325 for DYS392 to 0.786 for DYS385. Discrimination capacity was 92.7%. Allele frequencies diversity was 0.615. Intermediate alleles 17.2, 18.2 and 19.2 were found at DYS458 locus. A comparison with published data for the European minimal haplotype set showed the closest relationship to the Croatian capital of Zagreb and Bosnia and Herzegovina with significant genetic distance from Slovenia and Austria. The central Croatian population is now well characterized in terms of Y-chromosome STRs, thus providing a solid basis for further forensic and genetic epidemiology studies.

Effects of Reference Population and Number of STR Markers on positive evidence in Paternity Testing

Three sets of commonly used autosomal short tandem repeat (STR) markers (containing 15, 10 and 9 markers) and 14 databases from populations belonging to Africa, America, Asia and Europe were used to investigate how the selection of the population database and the number of considered markers would influence the statistical evidence that is usually produced to favour paternity. The study was based on a sample of 100 randomly chosen Finnish paternity trios collected during paternity testing case work and without any exclusion after use of 15 STR markers. Paternity Index, Probability of Paternity, Typical Paternity Index and Probability of Exclusion were computed and descriptive statistics were provided separately for trios (mother, child and putative father) and duos (obtained from trios but not considering the genetic information of the mother). This was done for all combinations of markers and databases. In trio cases the differences between results obtained are not statistically significant. However, especially in duo cases the use of 15 STR markers is recommended.

A case of chimerism in a paternity study

The STR profile of a phenotipically normal woman typed from blood tissue in a paternity case, revealed more than two alleles in some autosomal loci, result that was interpreted as a chimera due to the coexistence of two genetically distinct cell populations. The aim of this work was to solve the paternity study, elucidate the origin of the chimera, and evaluate its consequence in forensic genetics. Buccal epithelium and hair root tissues showed a single autosomal STR profile. Instead, blood tissue exhibited chimerism in seven out of the twenty autosomal loci tested. The paternity analysis was resolved comparing the unique STR pattern typed from buccal and hair root cells. The detection in blood tissue of the Y allele in Amelogenin locus and typing of a Y-chromosome haplotype confirmed the presence of male cells in the chimeric woman. The deduced male profile cannot be excluded as a son of the alleged father. Based on the results we interpret that the woman subject of the study is a partial or a whole-body chimera. Chimerism may be a pitfall in forensic investigations like paternity testing and crime cases.

Development of two new Mini-STR multiplex assay for typing archival Bouin's fluid-fixed paraffin-embedded tissues

Short amplicon autosomal short tandem repeat (Mini-STR) assay has proved to be a highly useful tool in forensic applications, especially for highly degraded DNA samples that typically result in partial profiles and total loss of information from regular STR amplicons. In this study two new quadruplex systems were designed to get nuclear DNA profile from degraded forensic casework samples. In order to obtain PCR products less than 120 bp in size, primer pairs of eight STR markers, included in available commercially multiplex PCR kits, were redesigned and assembled in two PCR-multiplexes: D8S1179, D3S1358, TPOX, D16S539 and CSF1P0, TH01, D13S317, D5S818. After validation, these two Mini-STR quadruplex were employed in paternity testing case that involved DNA extraction from archival postmortem Bouin's fluid-fixed paraffin-embedded tissue where commercial kit yielded low success. The results obtained with the present Mini-STR PCR-multiplexes proved clearly demonstrating their usefulness in analyzing degraded DNA samples.

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.

PedExpert: a computer program for the application of Bayesian networks to human paternity testing

PedExpert is a Windows-based Bayesian network software, especially constructed to solve problems in parentage testing that are complex because of missing genetic information on the alleged father and/or because they involve genetic mutations. PedExpert automates the creation and manipulation of Bayesian networks, implementing algorithms that convert pedigrees and sets of indispensable information (genotypes, allele frequencies, mutation rates) into Bayesian networks. This program has a novel feature that can incorporate information about gene mutations into tables of conditional probabilities of transmission of alleles from the alleged father to the child, without adding new nodes to the network. This permits using the same Bayesian network in different modes, for analysis of cases that include mutations or not. PedExpert is user-friendly and greatly reduces the time of analysis for complex cases of paternity testing, eliminating most sources of logical and operational error.

Effects of reference population and number of STR markers on paternity testing

Three sets of commonly used autosomal short tandem repeat (STR) markers (containing 15, 10 and 9 markers) and 14 databases from populations belonging to Africa, America, Asia and Europe were used to investigate how the selection of the population database and the number of considered markers would influence the statistical evidence that is usually produced to favour paternity. The study was based on a sample of 100 randomly chosen Finnish paternity trios collected during paternity testing case work and without any exclusion after use of 15 STR markers. Paternity index, power of evidence, typical paternity index and Random man excluded were computed and descriptive statistics were provided separately for trios (mother, child, alleged father) and duos (obtained from trios but not considering the genetic information of the mother). This was done for all combinations of markers and databases. In trio cases the differences between results obtained are not statistically significant. However, especially in duo cases the use of 15 STR markers is recommended.

A study of thirty autosomal Single Nucleotide Polymorphism markers in Hungarian population

Testing of thirty autosomal single nucleotide polymorphisms were performed in 218 independent Hungarian male and female samples. We applied this system to 24 paternity testing cases including 14 inclusions and 10 exclusions.

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 × 10 −5 and 2.2 × 10 −3, and the overall average mutation rate estimate was 8.4 × 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.

Analysis of single nucleotide polymorphisms and its application in a disputed paternity case

We investigated the distribution of allele frequencies for 16 single nucleotide polymorphism (SNP) loci (rs3761455, rs3788319, rs3747173, rs3827413, rs3788306, rs3788359, rs2020943, rs3788545, rs20386, rs20362, rs363780, rs20464, rs492539, rs363754, rs363759, and rs363765) in 120 unrelated healthy Japanese individuals on the basis of multiplexed single nucleotide primer extension using ABI PRISM SNaPshot™ Multiplex Kit and ABI PRISM™ 310 Genetic Analyzer. Simultaneously, we applied these databases to analyze a case of special paternity testing when the putative father and the child's mother were deceased. The DNA of the deceased putative father was extracted only from a formalin-fixed liver tissue.

The expected performance of single nucleotide polymorphism loci in paternity testing

We discuss the utility of single nucleotide polymorphism loci for full trio and mother-unavailable paternity testing cases, in the presence of population substructure and relatedness of putative and actual fathers. We focus primarily on the expected number of loci required to gain specified probabilities of mismatches, and report the expected proportion of paternity indices greater than three threshold values for these loci.

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)×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–Möller’s W-value was 0.9999995. The pM (matching probability) of the personal identification case was 2.22×10 −17. These data showed that this system was an excellent tool for use in forensic cases of paternity testing and personal identification.

Paternity cases when the alleged father is missing

New technologies of DNA analysis by STRs, LTRs and MHC genes, and the advance in statistical and mathematical calculations of complex paternity cases allowed paternity cases resolution when the alleged father is missing (AFM). Cases of civil state suppression during the dictatorial government (1976–1983) are investigated in our laboratory. In them, family groups are often incomplete in one or two generations. This study presents 31 cases of paternity testing with AFM carried out during 2001–2002 years. In these cases, only first grade relative of AFM and/or siblings or half siblings of the titular were available. In only 19 of them, alleged child's mother was available for the study. In all the 31 cases presented here, we could assign biological relationship between the alleged child and the alleged father's family members whose genetic information allowed us to reconstruct total or partially alleged father genotype.

Presence of two mutations between father and child in two cases of paternity testing

We report two cases of paternity testing presenting two inconsistencies between father and child in the same two STR-loci from a total of 16 STR and several VNTR loci examined.