Kinship Investigations Research Articles

Opt-in or out? Public perspectives on forensic DNA kinship investigations within the Dutch-speaking community

Forensic DNA kinship investigation involves analyzing genetic relationships between individuals to offer new leads for solving (cold) cases. Familial DNA matching has become a valuable asset in criminal case investigations, especially when traditional DNA methods hit dead ends. However, concerns surrounding ethical and privacy implications raised questions about its implementation and acceptance among the general public. The present study investigated the public perspectives regarding forensic DNA kinship investigations among 1710 Dutch-speaking Belgians using an online cross-sectional survey. The questionnaire consisted of three categories, including personal information, DNA knowledge, and their opinion on several familial DNA searching and investigative genetic genealogy related questions. The participants' average DNA knowledge score was 71 %, indicating a relatively high level of understanding of DNA-related concepts. Remarkably, the study revealed that 92 % of the participants expressed willingness to cooperate as a volunteer in a forensic DNA kinship investigation, irrespective of their scientific background or educational level. Key factors influencing participation included assurance of painless sampling and robust privacy safeguards. Participants lacking familiarity with DNA hesitated more towards participating in forensic DNA analysis, referring to "the fear of the unknown". Despite ethical and privacy concerns, the highly positive attitude towards forensic DNA analysis reflects a level of empathy and willingness to contribute to the pursuit of justice. Nearly all participants (95 %) agreed to use online DNA databases for resolving violent crimes with forensic genetic genealogy, but half emphasized the need for prior informed consent, referring to the current “opt-in” system. The results underscore the need for stringent regulations and ethical oversight to ensure the responsible use of genetic data while striking a balance between public safety and the protection of individuals' privacy rights. These findings add to the growing body of evidence regarding the potential benefits of forensic DNA kinship matching as a tool in criminal investigations, suggesting its potential future utilization and legalization.

Haplotype diversity of 17 Y-STR in the Iranian population

The current study aimed to evaluate Y chromosome haplotypes obtained from 1353 unrelated Iranian males using the AmpFlSTRTM YfilerTM kit; 1353 out of the 1353 identified haplotypes were unique. The haplotype diversity (HD) and discriminating capacity (DC) values were 1.00000 and 0.997, respectively. Analysis of genetic distance was performed using molecular variance (AMOVA) and multidimensional scaling plots (MDS), revealing a statistically significant difference between the study population and previous data reported for other Iranian populations and other neighboring countries. The present findings are likely to be useful for forensic casework analyses and kinship investigations.

Applications of X-Chromosome Short Tandem Repeats for Human Identification: A Review

The forensic DNA profiling technique has tremendously contributed to forensic human identification, an important aspect in forensic investigations. In instances whereby comparison samples are unavailable, utilization of short tandem repeats of X chromosome (X-STRs) may prove useful to resolve complex kinship investigations involving missing persons and mass disasters. Despite such evidential values, the use of X-STRs during investigations remains scarce in many Southeast Asian countries including Malaysia, requiring concerted efforts for establishing forensic statistical support for its diverse populations (especially the admixture populations), standardizing core loci and procedure, improving the knowledge among practitioners as well as developing suitable standard operating procedure for incorporating X-STRs analysis in the overall DNA profiling framework. Hence, this review paper aims to highlight the developments, applications and population data of X-STRs, as well as its challenges and future insights for forensic casework.

Y-STR Kits and Y-STR Diversity in the South African Population

The South African population consists of four ethnic groups, i.e., Blacks, Coloreds, Indians, and Whites, and is considered the most diverse conglomeration of humans. In addition to autosomal short tandem repeat (STR) variation, an important tool to study population diversity is Y-chromosome (Y)-STR analysis. Y-STRs aid in forensic investigations and provide essential data about paternal lineage origins. Y-STR kits consisting of an array of stable and rapidly mutating markers offer crucial information on a given population's genetic and haplotype diversity. This review discusses the development of Y-STR kits over the years and highlights some prominent Y-STR studies conducted on the South African population. The earliest Y-STR kit developed was the Y-PLEX™6, with the most recent being the UniQTyper™ Y-10 Multiplex. The South African population studies show varying data, with the “minimal haplotype” having low discrimination capacity among the ethnic groups and the UniQTyper™ Y-10 showing high genetic diversity among the ethnic groups of the country. There is a dearth of Y-STR studies on the South African population. With the advent of new Y-STR kits with increased discriminatory markers, additional studies are required to represent the South African population in the Y-STR databases. Considering the diversity of the South African population, establishment of a local/regional population database would be beneficial. In addition, data on the origins and prevalence of mutations and silent alleles should be obtained from STR datasets generated during kinship investigations (specifically, parentage tests) so that detailed information about the frequencies of mutations, silent alleles, and uniparental disomy in the South African population at Y STR loci can be estimated.

Analysis of recombination and mutation events for 12 X-Chr STR loci: A collaborative family study of the Italian Speaking Working Group Ge.F.I

According to the ISFG guidelines on the use of X-chromosome, the biostatistical evaluation in kinship analysis is based on a likelihood ratio approach, but since in calculation linkage and recombination events should be accounted for, an accurate estimate of mutation and recombination rates of X-markers analyzed is required. Due to the mode of genetic transmission and physical location, sometimes X-chromosome markers can be more informative than autosomal STRs and their analysis could be considered a supplementary tool in DNA testing.The increased demand to forensic laboratories for kinship investigations in complex cases explains the need not only to enlarge the Italian population database for 12 X-STRs routinely used for forensic application, but also to investigate the recombination fractions among markers.A collaborative exercise of the Italian Speaking Working Group Ge.F.I. was organized to evaluate mutation and recombination events in 12 X-STRs included in the Investigator Argus X12 kit. In order to explore the segregation stability, three-generation families (grandpa-mother-son) and two-generation families (mother-sons, father-daughters) for a total of 269 pedigrees were analyzed and calculations to estimate the recombination fractions between pairs of markers and mutation rates were performed. The statistical analysis showed evidence of inter- and intra-cluster recombination events, with almost free recombination for junction markers of linkage groups I and II and reduced recombination for linkage groups III and VI. We observed one- and two-step mutations, with an average value of 2.9 × 10−3.

Genetic variations and population data on five supplementary STR markers in Lebanon.

Population representative short tandem repeat (STR) allele frequencies are crucial for proper probabilistic interpretation of DNA forensic evidence. STR allele frequencies also provide information about the genetic diversity of a given population. The Lebanese population is characterized by the presence of more than 18 religious communities that have high recorded rates of endogamous and consanguineous marriages, where the choice of marriages is mainly influenced by their respective geographical distributions and religious affiliation. These factors could have led to an increase in complex DNA cases, whereby high numbers of STR markers are needed to help clear the case. Allele frequencies for 23 STR loci in the Lebanese population were recently estimated and published. The present study aims at estimating the STR allele frequencies for five supplementary STRs, namely, the LPL, F13B, FESFPS, F13A01, and Penta C STR markers, which are mainly used to resolve complex kinship investigations. A DNA database representative of the Lebanese population that comprises 505 Lebanese unrelated individuals was used to amplify the five STR systems, using the CS7 kit released by Promega. The allele frequencies for these STR systems were estimated, and a significant departure from the Hardy-Weinberg equilibrium was detected after Bonferroni correction for multiple tests at locus LPL, F13A01, and Penta C. The newly added systems appeared to have variation in their discriminative power among Lebanese individuals. Penta C showed the highest power of discrimination, whereas FESFPS showed the lowest power of discrimination. The estimated frequencies and population data could provide local DNA relationship testing laboratories with additional tools that help resolve complex DNA cases.

A GHEP-ISFG collaborative study on the genetic variation of 38 autosomal indels for human identification in different continental populations

A collaborative effort was carried out by the Spanish and Portuguese Speaking Working Group of the International Society for Forensic Genetics (GHEP-ISFG) to promote knowledge exchange between associate laboratories interested in the implementation of indel-based methodologies and build allele frequency databases of 38 indels for forensic applications. These databases include populations from different countries that are relevant for identification and kinship investigations undertaken by the participating laboratories. Before compiling population data, participants were asked to type the 38 indels in blind samples from annual GHEP-ISFG proficiency tests, using an amplification protocol previously described. Only laboratories that reported correct results contributed with population data to this study. A total of 5839 samples were genotyped from 45 different populations from Africa, America, East Asia, Europe and Middle East. Population differentiation analysis showed significant differences between most populations studied from Africa and America, as well as between two Asian populations from China and East Timor. Low FST values were detected among most European populations. Overall diversities and parameters of forensic efficiency were high in populations from all continents.

SNPs and STRs in forensic medicine. A strategy for kinship evaluation.

Some emerging technologies are used as strategies for the analyses of single nucleotide polymorphisms (SNPs) that have attracted much interest in recent years, applied to various scientific areas. They have been extensively used as markers to identify genes that underlie complex diseases and also to realize the potential of pharmacogenomics in relation to different drug responses. Additionally, SNPs have been shown to be very useful in forensic genetics resolving all kinds of legal problems, namely crime cases, disaster victim identification and paternity and kinship investigation testing. The low mutation rate of SNPs, makes these markers very suitable for relationship testing. In the great majority of the cases, analyses with the widely used sets of STR markers provide powerful statistical evidence but some of them remain with ambiguous results. Those include cases with complex pedigrees or cases with some problems, like mutations, that are inherent to the use of STRs. At this time several forensic laboratories are using SNPs especially to complement the study of STRs in some of their casework cases. This paper intends to analyze some of our casework examples and to providea data update on the joint use of STRs and autosomal SNPs in the evaluation and kinship calculation, one of the strategies currently used for this purpose, namely reviewing and comparing results published by various working groups.

SNP Markers as Additional Information to Resolve Complex Kinship Cases

Background: DNA profiling with sets of highly polymorphic autosomal short tandem repeat (STR) markers has been applied in various aspects of human identification in forensic casework for nearly 20 years. However, in some cases of complex kinship investigation, the information provided by the conventionally used STR markers is not enough, often resulting in low likelihood ratio (LR) calculations. In these cases, it becomes necessary to increment the number of loci under analysis to reach adequate LRs. Recently, it has been proposed that single nucleotide polymorphisms (SNPs) could be used as a supportive tool to STR typing, eventually even replacing the methods/markers now employed. Methods: In this work, we describe the results obtained in 7 revised complex paternity cases when applying a battery of STRs, as well as 52 human identification SNPs (SNPforID 52plex identification panel) using a SNaPshot methodology followed by capillary electrophoresis. Results: Our results show that the analysis of SNPs, as complement to STR typing in forensic casework applications, would at least increase by a factor of 4 total PI values and correspondent Essen-Möllerʼs W value. Conclusions: We demonstrated that SNP genotyping could be a key complement to STR information in challenging casework of disputed paternity, such as close relative individualization or complex pedigrees subject to endogamous relations.

Genetic data of 10 X-STRs in a population sample from Lima, Perú

Genetic population data for 10 X-STR (DXS6789, DXS9902, DXS7132, GATA31E08, DXS7133, DXS9898, DXS8378, DXS6809, DXS7423 and GATA172D05) were obtained from Lima population. The present study results support the usefulness of these markers in kinship investigation and also in population genetics studies.

Genetic polymorphism of 30 InDel markers for forensic use in Bangladeshi population

In this study, we genotyped a set of Bangladeshi population sample (n=132) using 30 InDel markers included in Investigator DIPplex PCR amplification kit (Qiagen, Germany). The forensic efficiency parameters for all the loci were calculated. Hardy–Weinberg equilibrium tests demonstrated no significant deviation from expected values (P>0.00167 after Bonferroni correction for multiple testing). The random probability of match and cumulative power of exclusion was found to be 2.87×10−12 and 0.99470, respectively, for the 30 loci. The high levels of power of discrimination (0.999999875) makes it well suited for identification of individuals. But relatively low range of TPI (0.791–1.179) and PE (0.0685–0.263) limits its usefulness in paternity and kinship investigations. The studied 30 InDel loci however offer a good supplementary tool for resolving challenging kinship studies and an efficient alternative to SNP typing in the studied population.

Using STR, MiniSTR and SNP markers to solve complex cases of kinship analysis

In complex kinship investigation, miniSTRs and SNPs have been frequently used in order to increase the likelihood ratio (LR), when the results obtained for the most commonly used STR multiplexes were not informative enough. In this work, we describe the results obtained when using a battery of 23 STRs, 3 miniSTRs and 52 SNPs to investigate three complex paternity cases where the father was not available, and one paternity case with bone samples, from which no results could be obtained for STRs (including the 3 miniSTRs, D10S1248, D14S1434 and D22S1045). In all cases, the additional information provided by the SNPforID 52plex identification panel was enough to achieve conclusive results.

Comparative evaluation of alternative batteries of genetic markers to complement autosomal STRs in kinship investigations: autosomal indels vs. X-chromosome STRs

Kinship investigations such as paternity are currently solved using sets of (commercially available) highly polymorphic autosomal short tandem repeats (STRs), which lead to powerful likelihood ratios (LR). Still, some difficult cases arise whenever the kinship is much more remote or if the alternative hypotheses are not correctly formulated due to the lack of information (for e.g. there is an unknown relationship between the alleged and the true fathers). In these situations, beyond the routinely used marker set, laboratories usually enlarge the number and/or the type of markers analysed. Among these, autosomal indels and X-chromosome STRs have gained popularity. The aim of this study was to compare the results obtained after complementing an initial set of autosomal STRs with indels or with X-chromosome-specific STRs in simulated paternity cases where the alleged father is a close relative of the real one. Results show that in paternity cases where a low number of incompatibilities are observed, the best strategy is to increase the number of autosomal STRs under analysis. Nevertheless, if these are not available, our study globally shows that in father-daughter duos, a set of 12 X-STRs is more advantageous than 38 highly diverse autosomal biallelic markers. Additionally, the usefulness of X-STRs was also evaluated in cases where only a close relative of the alleged parent (father or mother) is available for testing. For those situations where these markers have the power to exclude, strong LR values are obtained. In the remaining cases, LRs are usually weak and sometimes the results are more likely under the wrong kinship hypothesis.

Genetic Kinship Investigation from Blood Groups to DNA Markers

The forensic application of hereditary characteristics became possible after the discovery of human blood groups by Karl Landsteiner in 1901. The foundation for their use in kinship investigation was laid by Emil von Dungern and Ludwig Hirschfeld in 1910 by clarification of the inheritance of the ABO groups. Up to the middle of the 20th century further red cell membrane systems were discovered. From the 1920s Fritz Schiff and Georg Strassmann fought for the introduction of blood groups into forensic kinship investigation. A new era of hemogenetics was opened from 1955 as genetic polymorphisms were described in serum proteins. Starting in 1958 there followed the complex HLA system of white blood cells, which from 1963 was joined by polymophisms in erythrocyte enzymes. Therefore, from the 1980s, it was possible to clarify the majority of kinship cases with a combination of conventional markers. From 1990 to 2000 the conventional markers were gradually replaced by the more effective DNA markers. Simultaneously typing shifted from the phenotype level to the genotype level. The genomic structure of con ventional genetic markers could also now be explained. As a reflection of scientific progress the legal situation also changed, particularly in the form of the official guidelines for kinship investigation.

First application of the Investigator DIPplex indels typing kit for the analysis of ancient DNA samples

Kinship testing and identification of human remains in forensic and anthropological fields is commonly based on the analysis of short tandem repeats (STRs) or more seldom single nucleotide polymorphisms (SNPs). In this study, another type of genetic variations, insertion/deletion polymorphisms (indels) was used through the DIPplex indels typing kit (Qiagen) for such purpose. The objective was to evaluate the performance of the assay for the analysis of ancient DNA samples as well as the informativeness of the kit on kinship investigation. Although some limitations have been noticed, this work shows that indels are well suited for the analysis of degraded samples and that they might be an interesting strategy in addition to STRs typing.

Discrimination power of Investigator DIPplex loci in Finnish and Somali populations

In this study, the suitability of the Investigator DIPplex insertion/deletion polymorphism (indel) kit for forensic casework was assessed through the genotyping of 151 Finns and 175 Somalis. Allele frequency and heterozygosity (H) of this 30-indel marker set were determined, and forensic efficacy was evaluated through estimation of discrimination power (DP), match probability (MP), typical paternity index (TPI), power of paternity exclusion (PE), and polymorphic information content (PIC). A high level of discrimination power was observed for the marker set in both sample groups (CDP>0.9999). East-west population substructure found previously in uniparental markers within Finland was not evident for this autosomal set (E-W FST=0.003). High exclusion probability and low subdivision together demonstrate that these markers are well-suited for identification of individuals in Finland. However, values for typical paternity index and power of paternity exclusion were low (TPI range Finns=0.750–1.190, PE=0.996; TPI Somalis=0.680–1.090, PE=0.986) in comparison to standard STR sets, and thus indels are not recommended for use in paternity or kinship investigations, except as a supplement to other more powerful tools.

A method for the analysis of 32 X chromosome insertion deletion polymorphisms in a single PCR

Studies of human genetic variation predominantly use short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs) but Insertion deletion polymorphisms (Indels) are being increasingly explored. They combine desirable characteristics of other genetic markers, especially the possibility of being analysed using short amplicon strategies, which increases the ease of analysis, contributing to justify their interest in population and forensic genetics. After the advent of autosomal and uniparental genomes (mtDNA and Y chromosome), these fields of research are also focusing on the X chromosome, given its special transmission pattern. The X chromosome markers brought new insights into the history of modern human populations and also proved useful in forensic kinship investigations, namely in deficient relationship cases and in cases where autosomes are uninformative. This work describes an X-Indel multiplex system amplifying 32 biallelic markers in one single PCR. The multiplex includes X-Indels shown to be polymorphic in the major human population groups and follows a short amplicon strategy. The set was applied in the genetic characterization of sub-Saharan African, European and East Asian population samples and revealed high forensic efficiency, as measured by the accumulated power of discrimination (0.9999990 was the lowest value in males and 0.999999999998 was the highest in females) and mean exclusion chance varied between 0.998 and 0.9996 in duos and between 0.99997 and 0.999998 in trios. Finally, a segregation analysis was performed using trio constellations of father-mother-daughters in order to address the transmission pattern and assess mutation rates of this type of markers.

Concordance Study between the AmpFlSTR® SGM Plus™ and PowerPlex® 16 System Human Identification Kits in Bangladeshi Population

In this study, we are reporting the concordance study between profiles from AmpFlSTR ® SGM plus™ and that of PowerPlex®16 system kits in Bangladeshi Bangali population. DNA samples from 234 unrelated Bangladeshi Bangali individuals were evaluated employing both the SGM plus™ and PowerPlex ® 16 system human identification kits. Complete consistency was observed in 233 out of 234 profiles which represents substantial degree of concordance amounting 99.57% between these two kits. Only one discrepancy encompassing the dropout of allele 12 at D16S539 loci in PowerPlex ® 16 system was observed. Sequence analysis revealed two mutational events; one at 16 bp distal and another next to the 3' end of the PowerPlex 16 reverse primer of D16S539 locus. This study has shown the significance of using of alternative set of primer to address the false homozygosity issue as well as of bringing attention regarding the fact of discrepant typing from different sets of primers to the scientific community during database handling and identity or kinship investigations. and Santals, mainly labourers in the tea garden at Sylhet district. The Mongolian group is confined to the hills along the southern spur of the Shilong plateau, in Chittagong hill tracts and Madhupur forest. Chakam, Tripura, Garo, Murang and Moghs are the major Mongolid tribes in Bangladesh. The individuals recruited in this study belongs to only the mainstream Bangali population.

Genetic data of 10 X-STR in two Native American populations of Argentina

We present genetic data for ten X-STRs (DXS8378, DXS9898, DXS7133, GATA31E08, GATA172D05, DXS7423, DXS6809, DXS7132, DXS9902 y DXS6789) in two Native American populations from the North and Northwest regions of Argentina, namely Toba and Colla. The present study results support the usefulness of these markers in kinship investigation and also in population genetics studies.

Use of eight X-chromosomal STRs in paternity investigation

A new commercial kit, Mentype ® Argus X-8, which analyzes eight X-chromosomal STR markers – DXS7132, DXS7423, DXS8378, DXS10074, DXS10101, DXS10134, DXS10135 and HPRTB, was used. A hundred and one South Portuguese Caucasian individuals and 60 paternity investigation cases, previously performed with routine STRs markers, were studied. Allele frequencies were estimated for the eight X-STRs. More than five exclusions between the alleged father and the female child were observed in almost all exclusion cases, especially in DXS10101, DXS10134 and DXS10135 loci. This set of eight X-chromosomal STRs appears to be quite useful for father–daughter studies and in some kinship investigations.