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At least 19 recordsLinked to original sources
PubMed2026

A rare and atypical case of long-distance indirect DNA transfer: Contamination from an investigator never present at the scene.

To maximize the usefulness of DNA obtained from biological samples in forensic genetics, it is crucial to avoid DNA contamination throughout all procedures, from sample collection at crime scenes to STR profile generation in DNA laboratories. This study reports a rare and atypical case of DNA contamination in a forensic setting. During the analysis of biological evidence from a cold case preserved for 18 years, the STR profile obtained from the surface of a plastic bag matched that of an investigator, identified through the DNA elimination database. Case reconstruction confirmed that the investigator-who was located 80 km from the DNA laboratory and had never entered the crime scene or the sample storage room-was not a suspect and that the obtained STR profile originated from contamination. The most plausible explanation for the contamination was indirect transfer: investigator's DNA had adhered to a colleague's clothing and was subsequently dislodged and deposited onto the surface of the plastic bag as the colleague approached the sample pretreatment area. This study integrates trace DNA profiling of challenged samples with rapid contamination investigation and proposes prevention and control measures. This case underscores that, although DNA is widely regarded as the "gold standard" in forensic genetics, its interpretation must be considered within the context of the entire case. Conclusions should not be drawn based solely on a single DNA result.

Humans↗
PubMed2026

pSTRminer: integrated bioinformatic software for genome-wide identification and population-scale evaluation of polymorphic short tandem repeats.

Animal forensic genetics plays a critical role in criminal investigations by providing crucial evidence through domestic animal individualization and wildlife species identification. While human forensic genetics benefits from standardized short tandem repeats (STR) genotyping systems, animal forensic applications encounter significant challenges, including the limited availability of validated STR markers, the prevalence of error-prone dinucleotide STRs (di-STRs), and insufficient integration of population data. To address these challenges, we developed pSTRminer, an integrated bioinformatic tool that automates genome-wide STR mining and polymorphism evaluation. By applying pSTRminer to domestic cattle (Bos taurus), we identified 775,444 STRs de novo from the reference genome and genotyped them using whole-genome sequencing data from 60 Chinese and 111 African cattle to evaluate polymorphism across diverse genetic backgrounds. This led to the development of the cattle STR database (CSDB), comprising loci with a genotyping success rate&#x2009;&#x2265;&#x2009;40% and polymorphism information content (PIC)&#x2009;&#x2265;&#x2009;0.5. Experimental validation of 30 randomly selected tetranucleotide STRs (tetra-STRs) and 33 di-STRs via next-generation sequencing in a local Chinese cattle population (n&#x2009;=&#x2009;145) confirmed marker reliability. Although tetra-STRs had lower average polymorphism levels, they exhibited significantly lower stutter ratios (p&#x2009;<&#x2009;0.05), providing a viable path for identifying discriminative markers with fewer artifacts. Systematic screening revealed that certain tetra-STRs could surpass di-STRs in polymorphism. In conclusion, pSTRminer provides a scalable framework for developing standardized STR panels, facilitating the identification of robust and informative markers in forensic applications.

Bioinformatic software↗
PubMed2026

Assessing the influence of different alignment tools on the accuracy of a forensic epigenetic clock.

MOTIVATION: DNA methylation (DNAm) has long been a commonly investigated biomarker in biomedical research. The current gold standard for DNAm detection is bisulfite sequencing which requires dedicated alignment tools that can handle reduced sequence complexity. One commonly used application of DNAm are epigenetic clock measurements. These clocks have been adapted by many fields for their specific needs, including forensic genetics. Here, epigenetic clocks were designed to help estimate the chronological age of a biological stain donor for investigative purposes. RESULTS: In this study, data generated with a well-established forensic epigenetic clock is aligned with four different bisulfite-specific alignment tools: "Bwa-meth," "Abismal," "Bismark," and "BS-Seeker2." For each tool, we tested up to six different settings, altering parameters such as the maximum number of mismatches or the score function setting. The goal was to investigate whether the final predicted ages differed considerably between the tested alignment tools and settings. Quality controls such as read depth, precision, recall, F1 score, and alignment run time were also assessed. To allow other researchers to easily perform such methylation comparison analyses on their own data, a Shiny app called "MethylAge Explorer" was developed within this study. None of the tested settings for the three alignment tools "Abismal," "Bismark," and "BS-Seeker2" outperformed the originally used alignment tool "Bwa-meth" in terms of age prediction accuracy. However, differences in final age predictions were observed between the different alignment tools. Therefore, it is necessary to be aware of which alignment tool to use for particular epigenetic clocks. AVAILABILITY AND IMPLEMENTATION: The data underlying this article and the code for the shiny app are available on GitHub (https://github.com/charlsut/methylage_explorer).

DNA Methylation↗
PubMed2024

Private detection of relatives in forensic genomics using homomorphic encryption.

BACKGROUND: Forensic analysis heavily relies on DNA analysis techniques, notably autosomal Single Nucleotide Polymorphisms (SNPs), to expedite the identification of unknown suspects through genomic database searches. However, the uniqueness of an individual's genome sequence designates it as Personal Identifiable Information (PII), subjecting it to stringent privacy regulations that can impede data access and analysis, as well as restrict the parties allowed to handle the data. Homomorphic Encryption (HE) emerges as a promising solution, enabling the execution of complex functions on encrypted data without the need for decryption. HE not only permits the processing of PII as soon as it is collected and encrypted, such as at a crime scene, but also expands the potential for data processing by multiple entities and artificial intelligence services. METHODS: This study introduces HE-based privacy-preserving methods for SNP DNA analysis, offering a means to compute kinship scores for a set of genome queries while meticulously preserving data privacy. We present three distinct approaches, including one unsupervised and two supervised methods, all of which demonstrated exceptional performance in the iDASH 2023 Track 1 competition. RESULTS: Our HE-based methods can rapidly predict 400 kinship scores from an encrypted database containing 2000 entries within seconds, capitalizing on advanced technologies like Intel AVX vector extensions, Intel HEXL, and Microsoft SEAL HE libraries. Crucially, all three methods achieve remarkable accuracy levels (ranging from 96% to 100%), as evaluated by the auROC score metric, while maintaining robust 128-bit security. These findings underscore the transformative potential of HE in both safeguarding genomic data privacy and streamlining precise DNA analysis. CONCLUSIONS: Results demonstrate that HE-based solutions can be computationally practical to protect genomic privacy during screening of candidate matches for further genealogy analysis in Forensic Genetic Genealogy (FGG).

Humans↗
PubMed2026

Genetic Identification of Burned Human Remains: A Systematic Review.

Background/Objectives: DNA-based identification of degraded human remains represents a major challenge in forensic science, particularly in cases involving burned, fragmented, or commingled bodies. Advances in forensic genetics have expanded the analytical capabilities for such samples; however, the effectiveness of different approaches and their integration within Disaster Victim Identification (DVI) workflows remain heterogeneous. This systematic review aims to critically evaluate current evidence on DNA-based identification of degraded remains, focusing on methodological strategies, emerging genomic technologies, and DVI applications, while integrating laboratory evidence and operational forensic practice into a structured analytical framework. Methods: A systematic literature search was conducted in Scopus and Web of Science from database inception to 5 June 2026, following PRISMA 2020 guidelines. Eligible studies included original research addressing DNA analysis of degraded, thermally altered, or highly compromised human remains in forensic or DVI contexts. After a multistep screening process involving title/abstract and full-text evaluation, 37 studies were included. Data were extracted and organized into three thematic categories: (i) core DNA analysis, (ii) advanced molecular technologies, and (iii) DVI case applications. Results: The findings demonstrate that DNA recovery from degraded remains is influenced by thermal exposure, tissue type, and sampling strategy. Teeth and dense cortical bone consistently provide higher DNA yield. While autosomal STR profiling remains the primary analytical approach, its limitations in highly degraded samples are mitigated through the complementary use of mitochondrial DNA (mtDNA), Y-chromosome STRs (Y-STRs), and SNP markers, together with advanced sequencing technologies such as massively parallel sequencing (MPS). Emerging technologies, including rapid DNA systems and predictive models based on macroscopic indicators, significantly enhance efficiency and success rates. DVI studies report identification rates exceeding 90-95% when multidisciplinary and structured workflows are applied. The evidence further supports a flexible triage-based analytical strategy, in which marker selection is guided by tissue preservation and degradation level. Conclusions: DNA-based identification of degraded human remains has evolved into an adaptive, multi-level forensic process. Successful outcomes rely on the integration of optimized sampling, hierarchical genetic analysis, and coordinated DVI strategies. The findings support a triage-based framework that links tissue selection, degradation assessment, and analytical methodology to maximize identification success. Future developments should focus on predictive models, advanced genomic tools, and standardized workflows to further improve identification in challenging forensic scenarios.

Humans↗
PubMed2026

Forensic applicability of genetic profile generation from hair roots and shafts: Integration of retrotransposon polymorphisms and morphological predictors.

Genetic profiles were successfully obtained from hair samples both directly plucked from the scalp and indirectly from personal items such as combs and hairbrushes. Additionally, 100 genetic profiles were generated from buccal swabs from all donors, allowing the calculation of population allele and genotype frequencies. Complete genetic profiles were recovered from samples containing less than 0.012&#x202f;ng of total nuclear DNA. Nuclear DNA yield per hair root was highly variable, whereas hair shafts yielded up to 2&#x202f;ng of total nuDNA and in some cases less than 0.1&#x202f;ng. Multiple correspondence analysis (MCA) revealed that hair growth phase and the presence of a root were not significantly associated with successful profile recovery; instead, greater hair thickness and direct sampling correlated with higher success rates. In certain cases, the Insertion/Null (INNUL) markers system, InnoTyper 21, outperformed the Power Plex Fusion 6&#x202f;C STR kit. For forensic purposes, using the entire hair shaft provided better profiling outcomes than using the root alone. All Insertion/Null (INNUL) markers were in Hardy-Weinberg equilibrium, except for a few loci showing minor linkage disequilibrium. These results highlight the analytical potential of INNUL markers for obtaining nuclear DNA profiles from hair, even in challenging forensic contexts.

Humans↗
PubMed2026

[Empirical Classification of Tri-Allelic Genotype Cases and Parentage Index Calculation].

OBJECTIVES: To standardize the calculation method of the parentage index (PI) for short tandem repeat (STR) tri-allelic genotypes, thereby ensuring the accuracy and reliability of parentage tes&#x2011; ting conclusions. METHODS: A systematic analysis of 160 real cases was conducted. A classification system was constructed based on the occurrence mechanisms and inheritance patterns of STR tri-alleles, and the PI calculation method was optimized by integrating previous research findings with empirical data. RESULTS: A mechanism-based classification system for STR tri-allelic genotypes was established, comprising Type I (2 subtypes), Type II (6 subtypes), and the trisomic type (2 subtypes). On this basis, a standardized PI calculation method covering all categories of STR tri-allelic genotypes was developed. CONCLUSIONS: This study provides methodological guidance for the scientific and standardized calculation of PI for STR tri-allelic genotypes and offers an important reference for the formulation and refinement of relevant industry standards.

Humans↗
PubMed2026

Application efficacy evaluation of the STRSeqTyper122 kit and the FASTASeq 300 second generation sequencer in kinship identification.

Forensic DNA technology is the method of choice for kinship identification. However, existing standard methods still have certain limitations in accurately determining the range of kinship relationships. China's independently developed second generation sequencing technology and equipment are expected to enhance the capability of forensic DNA kinship identification. In this study, we utilized the STRSeqTyper122 second generation sequencing STR typing kit and the FASTASeq 300 second generation sequencer to analyze 107 real kinship samples. The analysis included 63 autosomal STR loci, 42 Y-STR loci, 16 X-STR loci, and one gender-determining locus, Amel. The samples covered various kinship relationships, including 113 parent-child pairs, 48 full-sibling pairs, 76 uncle-nephew pairs, 66 grandparent-grandchild pairs, and 4 half-sibling pairs. Combined with simulated data, the ITO method was applied to calculate the cumulative likelihood ratio (CLR) for different levels of kinship based on the length polymorphism and sequence polymorphism of autosomal STR loci, systematically evaluating the practical application performance of this system in kinship identification. The results showed that, using log10CLR values of 4 and -4 as thresholds, the system achieved 100% efficiency in identifying real parent-child and full-sibling relationships. For second degree kinship identification, the system efficiency based on simulated length polymorphism data was 55.2%, while sequence polymorphism improved it to 75.11%. For real sample data, length polymorphism based efficiency was 54.45%, and sequence polymorphism based efficiency reached 76.71%. The findings indicate that the STRSeqTyper122 kit holds significant value in first degree kinship identification. Sequence polymorphism can improve second degree kinship identification efficiency to over 75%.

Humans↗
PubMed2026

Genomic Tracking of Market-Derived Bull Shark Fins Back to Source Population of Origin.

International trade of shark fins remains difficult to monitor because products are rarely labelled to species and are often highly processed, resulting in severely degraded DNA. For several shark species listed under Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES), this limits external verification of source populations supplying global trade hubs. Here, we assess whether nuclear genomic approaches can be applied to market-derived bull shark (Carcharhinus leucas) fins to determine their population of origin. We analysed dried fin trimmings collected from retail vendors in Hong Kong SAR, one of the world's largest dried shark fin trade hubs, using a targeted DArTcap single nucleotide polymorphism (SNP) panel, originally developed for population genomic studies of this species. Despite substantial DNA degradation, genomic libraries were successfully obtained for most samples, yielding sufficient SNP data to perform robust provenance and sex assignment. Using a Bayesian mixed-stock analysis, most fin samples were assigned to the Indo-West Pacific (71.4%), with smaller contributions from the western Atlantic (22.6%) and eastern Pacific (3.0%). Genetic sex assignment revealed twice as many males as females, although results indicated a conservative bias towards male assignment due to the limited number of X-linked markers available in degraded samples. Our results demonstrate that genome-wide targeted approaches can be effectively applied to highly processed shark fin products to infer population sources and sex composition. This study provides proof-of-concept for integrating genomics into shark trade monitoring, highlighting its potential to improve traceability, support CITES implementation and inform conservation and fisheries management, particularly for species with well-resolved population structure.

Animals↗
PubMed2025

Uncovering new lineages in the Sunda pangolin (Manis javanica) with museum mitogenomics.

Accurately identifying evolutionarily significant units (ESUs) is crucial for conservation planning, especially for species like pangolins threatened by overhunting and habitat loss. ESUs help categorize different pangolin populations, aiding in understanding their genetic diversity and distribution, which is vital for targeted conservation efforts. This research generated mitochondrial genomes from historical museum specimens of Sunda pangolins (Manis javanica) from underrepresented locations, uncovering a new evolutionary lineage from the Mentawai Islands that diverged from Indochina and west Sundaland populations around 760 000 years ago. This population thereby represents a divergent ESU with a small distribution, important for conservation planning. The novel sequences provide resources for forensic labs tracing the origin of confiscated scales and shed light into the potential distribution of the 'mysterious pangolin'. Additionally, this research confirmed the presence of the two major M. javanica lineages in Java and extended the known distribution of the eastern clade to Bali and East Kalimantan. Our findings potentially suggest a recent bottleneck and postglacial expansion of pangolins across Indochina and west Sundaland. Further investigation with genomic and morphological evidence, contact area sampling and type sequencing will be required to evaluate the taxonomic status of different M. javanica lineages and M. culionensis.

Genomics↗
PubMed2024

Sequencing the orthologs of human autosomal forensic short tandem repeats provides individual- and species-level identification in African great apes.

BACKGROUND: Great apes are a global conservation concern, with anthropogenic pressures threatening their survival. Genetic analysis can be used to assess the effects of reduced population sizes and the effectiveness of conservation measures. In humans, autosomal short tandem repeats (aSTRs) are widely used in population genetics and for forensic individual identification and kinship testing. Traditionally, genotyping is length-based via capillary electrophoresis (CE), but there is an increasing move to direct analysis by massively parallel sequencing (MPS). An example is the ForenSeq DNA Signature Prep Kit, which amplifies multiple loci including 27 aSTRs, prior to sequencing via Illumina technology. Here we assess the applicability of this human-based kit in African great apes. We ask whether cross-species genotyping of the orthologs of these loci can provide both individual and (sub)species identification. RESULTS: The ForenSeq kit was used to amplify and sequence aSTRs in 52 individuals (14 chimpanzees; 4 bonobos; 16 western lowland, 6 eastern lowland, and 12 mountain gorillas). The orthologs of 24/27 human aSTRs amplified across species, and a core set of thirteen loci could be genotyped in all individuals. Genotypes were individually and (sub)species identifying. Both allelic diversity and the power to discriminate (sub)species were greater when considering STR sequences rather than allele lengths. Comparing human and African great-ape STR sequences with an orangutan outgroup showed general conservation of repeat types and allele size ranges. Variation in repeat array structures and a weak relationship with the known phylogeny suggests stochastic origins of mutations giving rise to diverse imperfect repeat arrays. Interruptions within long repeat arrays in African great apes do not appear to reduce allelic diversity. CONCLUSIONS: Orthologs of most human aSTRs in the ForenSeq DNA Signature Prep Kit can be analysed in African great apes. Primer redesign would reduce observed variability in amplification across some loci. MPS of the orthologs of human loci provides better resolution for both individual and (sub)species identification in great apes than standard CE-based approaches, and has the further advantage that there is no need to limit the number and size ranges of analysed loci.

Animals↗
PubMed2026

Detection rate of pathogenic variants by postmortem genetic testing for sudden cardiac death among children and young adults: systematic review and meta-analysis.

PURPOSE: Postmortem genetic testing (PMGT) can clarify the causes of sudden cardiac death (SCD) in children and young adults and provide preventive care for relatives. We systematically reviewed studies to estimate the detection rate of pathogenic variants identified by PMGT in SCD cases aged 1-50 years and examined factors influencing detection rates. METHODS: Ovid MEDLINE and Ovid Embase were searched for observational studies on PMGT in cases of SCD, records in duplicate were screened, and study- and variant-level data were extracted. Risk of bias was assessed using the Joanna Briggs Institute checklist. The pooled detection rates were estimated using random-effects meta-analysis, and heterogeneity was explored based on subgroup and meta-regression analyses. RESULTS: Sixty-six studies (4,452 cases from 23 countries) were included. The pooled detection rate was 19% (95% confidence interval, 15% to 24%). Among the detected pathogenic variants, 76% were found in genes included on the ACMG Secondary Findings list. Higher detection rates were associated with earlier publication years, lower mean age, and lower risk of bias. Substantial between-study heterogeneity persisted (I2 = 91%) despite the subgroup and meta-regression analyses. CONCLUSION: PMGT can be used to identify pathogenic variants in young SCD cases, however, there is considerable heterogeneity in study conditions.

Forensic genetics↗
PubMed2024

An easy-to-use pipeline to analyze amplicon-based Next Generation Sequencing results of human mitochondrial DNA from degraded samples.

Genome and transcriptome examinations have become more common due to Next-Generation Sequencing (NGS), which significantly increases throughput and depth coverage while reducing costs and time. Mitochondrial DNA (mtDNA) is often the marker of choice in degraded samples from archaeological and forensic contexts, as its higher number of copies can improve the success of the experiment. Among other sequencing strategies, amplicon-based NGS techniques are currently being used to obtain enough data to be analyzed. There are some pipelines designed for the analysis of ancient mtDNA samples and others for the analysis of amplicon data. However, these pipelines pose a challenge for non-expert users and cannot often address both ancient and forensic DNA particularities and amplicon-based sequencing simultaneously. To overcome these challenges, a user-friendly bioinformatic tool was developed to analyze the non-coding region of human mtDNA from degraded samples recovered in archaeological and forensic contexts. The tool can be easily modified to fit the specifications of other amplicon-based NGS experiments. A comparative analysis between two tools, MarkDuplicates from Picard and dedup parameter from fastp, both designed for duplicate removal was conducted. Additionally, various thresholds of PMDtools, a specialized tool designed for extracting reads affected by post-mortem damage, were used. Finally, the depth coverage of each amplicon was correlated with its level of damage. The results obtained indicated that, for removing duplicates, dedup is a better tool since retains more non-repeated reads, that are removed by MarkDuplicates. On the other hand, a PMDS = 1 in PMDtools was the threshold that allowed better differentiation between present-day and ancient samples, in terms of damage, without losing too many reads in the process. These two bioinformatic tools were added to a pipeline designed to obtain both haplotype and haplogroup of mtDNA. Furthermore, the pipeline presented in the present study generates information about the quality and possible contamination of the sample. This pipeline is designed to automatize mtDNA analysis, however, particularly for ancient samples, some manual analyses may be required to fully validate results since the amplicons that used to be more easily recovered were the ones that had fewer reads with damage, indicating that special care must be taken for poor recovered samples.

DNA, Mitochondrial↗
PubMed1976

Immunofixation. I. General principles and application to agarose gel electrophoresis.

Immunofixation offers the worker an economical means of physically locating a protein in an electrophoretic strip and is ideally suited to forensic medicine, genetic studies, or research. The method is as simple and economical as the commonly used one- or two-dimensional immunoelectrophoresis, yet yields considerably more information.

Blood Protein Electrophoresis↗
PubMed2026

Wildlife forensic DNA evidence links a suspected vehicle to a fatal lowland tapir (Tapirus terrestris) collision in Misiones, Argentina.

Vehicle collisions are recognized as a major driver of biodiversity loss, particularly in road-dense landscapes, exceeding the impact of invasive species and wildlife trafficking. For large-bodied, slow-reproducing, and low-abundance species, such as the lowland tapir (Tapirus terrestris), this threat can have major impacts. Here, we present a wildlife forensic investigation in Misiones, Argentina, involving a tapir, a species afforded the highest level of legal protection as a Provincial Natural Monument. The fatal hit-by-vehicle (HBV) incident occurred in northern Misiones on 31 March 2019 along Provincial Route 19, in a portion that bisects Parque Provincial Urugua-&#xed;, with the driver involved in the collision leaving the scene. The suspect was later located and claimed that the damage to the vehicle resulted from a collision with a horse (Equus caballus) rather than a tapir. To legally resolve the incident, DNA (hair and blood) recovered from the suspected vehicle's bumper (evidence) was compared with tissue samples from the tapir carcass (reference). Genetic confirmation of species identity used a 110-bp region of the mitochondrial cytochrome b gene, and individual identity was assessed using 12 species-specific microsatellite loci. These analyses confirmed that all evidence matched the tapir carcass at both species and individual levels, strongly supporting the association between the suspected vehicle and the HBV tapir, and refuting the alternative explanation proposed by the driver. This case demonstrates the value of using wildlife forensic genetics to reconstruct wildlife-vehicle collisions, supporting environmental law enforcement, and strengthening conservation efforts in the Atlantic Forest of Misiones, Argentina.

Animals↗