Forensic Science International[JOURNAL]
Sun
200 papers
Transferring a microhaplotype-specific probabilistic genotyping model from targeted amplification to hybridization capture: A proof-of-concept study of a 100-locus panel for DNA mixtures.
Yang C, Cao Y, Wang Y … +6 more , Hu Y, Hou T, Wang H, Shan T, Zhu Q, Zhang J
Forensic Sci Int Genet · 2026 Jun · PMID 42242031 · Publisher ↗
Probabilistic genotyping (PG) has become the standard framework for evaluating forensic DNA mixtures, yet most implementations were developed for STR data and PCR-based enrichment. Microhaplotypes (MHs) provide high alle...
Probabilistic genotyping (PG) has become the standard framework for evaluating forensic DNA mixtures, yet most implementations were developed for STR data and PCR-based enrichment. Microhaplotypes (MHs) provide high allele diversity without stutter and are attractive for mixture deconvolution, particularly when combined with hybridization capture for degraded or limited DNA. Here, we developed a 100-locus hybridization capture MH panel and assessed its performance for mixture interpretation using two continuous PG models: (i) a MH-specific Truncated Gaussian (TG) model previously developed by our group for targeted amplification MH-MPS data, and (ii) the gamma-based model implemented in EuroForMix (EFM). Panel performance was first examined using sensitivity (0.5, 0.125, and 0.0625 ng; triplicates) and repeatability/consistency (10 individuals, 0.5 ng; duplicates) experiments. We then analyzed two- and three-person mixtures with increasing mixture imbalance (2-person: 1:1-1:40; 3-person: 1:1.5:3-1:4:20; triplicates). Across all mixtures, true contributors yielded likelihood ratios (LRs) > 1 under both models, with all tested non-contributors yielding LRs < 1. For two-person mixtures, major-contributor deconvolution accuracy approached 100%, whereas minor-contributor accuracy peaked at 83% (1:5) and declined with increasingly imbalanced mixtures. In three-person mixtures, minor-contributor accuracy depended strongly on relative proportions among contributors and showed non-monotonic trends. Overall, the TG model produced higher LRs and improved deconvolution for minor contributors compared with EFM, supporting transferability of the TG framework from targeted amplification to hybridization capture MH-MPS data. These results provide a preliminary practical foundation for probabilistic interpretation of hybridization capture microhaplotypes in forensic mixtures.
Targeting ultrashort fragments: Development and validation of a 44-InDel panel for highly degraded DNA.
Li Y, Wang Y, Fu X … +3 more , Xie Q, Li J, Cai J
Forensic Sci Int Genet · 2026 May · PMID 42242030 · Publisher ↗
Degraded samples are common yet challenging evidence types in forensic casework, and obtaining complete profiles from highly degraded samples has long been a major difficulty in forensic DNA analysis. However, there is a...
Degraded samples are common yet challenging evidence types in forensic casework, and obtaining complete profiles from highly degraded samples has long been a major difficulty in forensic DNA analysis. However, there is a lack of effective methods for obtaining complete profiles from single-source highly degraded samples. Insertion/deletion (InDel) genetic markers, which combine the advantages of short tandem repeats (STRs) and single nucleotide polymorphisms (SNPs), are widely distributed throughout the human genome, exhibit low mutation rates, possess short amplicon sizes, and are compatible with capillary electrophoresis (CE) platforms. These features make InDels ideal genetic markers for the analysis of highly degraded forensic samples. To address this issue, we selected 44 InDel genetic markers with amplicon sizes of no more than 125 bp, together with an amelogenin locus, to establish a five-dye multiplex detection system for accurate genotyping of highly degraded DNA samples. Following the guidelines of the Scientific Working Group on DNA Analysis Methods (SWGDAM), the system was evaluated in terms of sensitivity, inhibitor tolerance, species specificity, and performance on highly degraded samples. Sensitivity analysis demonstrated that complete and reliable profiles could be obtained with as little as 62.5 pg of input DNA. In degradation studies, the 44-InDel panel generated complete profiles from DNA subjected to 60 min of boiling, demonstrating a clear advantage over STR-based methods in the analysis of highly degraded samples. Population analysis was conducted using 180 samples from the Southern Han Chinese population, yielding an average observed heterozygosity (Ho) of 0.4898 for all loci. The combined random match probability (CMP) and cumulative probability of exclusion (CPE) were calculated as 2.9522 × 10⁻¹ ⁹ and 0.99985, respectively. The results demonstrated that the 44-InDel panel is highly suitable for individual identification of highly degraded forensic samples and serves as a valuable complementary tool for paternity testing.
SiMSen-Seq STR sequencing across five laboratories enables lowered noise thresholds and improved allele calling.
Gynnå AH, Sidstedt M, Kiesler KM … +11 more , Staadig A, Lindgren Å, Kebede FT, Håkansson J, Steffen CR, Österlund T, Bogestål Y, Tillmar A, Vallone PM, Ståhlberg A, Hedman J
Forensic Sci Int Genet · 2026 Jun · PMID 42242029 · Publisher ↗
Unique molecular identifiers (UMI) can be used in forensic STR sequencing to reduce the level of analytical artifacts. Here, we perform an interlaboratory study across five independent sites where the previously develope...
Unique molecular identifiers (UMI) can be used in forensic STR sequencing to reduce the level of analytical artifacts. Here, we perform an interlaboratory study across five independent sites where the previously developed UMI-based SiMSen-Seq STR assay is applied at each laboratory to both single-source and mixed samples. The assay showed consistent results between laboratories and more than 90% of the expected alleles were detected with 31 pg DNA of template. The assay tolerated ten times higher PCR inhibitor concentrations compared to an established commercial STR sequencing method. The combined results were used to determine stutter and noise thresholds, which were applied for allele calling, allowing an estimation of the sensitivity for minor contributor alleles in mixtures. We found that the SiMSen-Seq STR method is robust across laboratories and different types of PCR and sequencing equipment and that it allows for calling of alleles from contributors of smaller proportions compared to currently commercially available non-UMI STR sequencing methods.
Microspectrophotometry in Forensic Paint Analysis: The Renaissance of a Technique - Comparison of Transmittance, Reflectance and Fluorescence Modes.
Bedjil S, Massonnet G
Forensic Sci Int · 2026 Jun · PMID 42241942 · Publisher ↗
Microspectrophotometry (MSP) is a powerful analytical technique that enables objective colour measurements and provides valuable complementary information to vibrational spectroscopies such as FTIR and Raman in forensic...
Microspectrophotometry (MSP) is a powerful analytical technique that enables objective colour measurements and provides valuable complementary information to vibrational spectroscopies such as FTIR and Raman in forensic paint analysis. In this study, the discriminating power of MSP was evaluated for the differentiation of 34 visually similar red household paints sharing the same colour code, previously investigated by Muehlethaler et al. [1]. Measurements were performed using three acquisition modes, transmittance, reflectance, and fluorescence (UV, Blue, and Green excitations), with a Tidas S MSP 800 system. Several spectral pretreatment strategies and similarity metrics were compared in order to assess the discriminating performance of each acquisition mode. The results show that reflectance provides the highest discriminating power, followed by UV and blue fluorescence, whereas transmittance and green fluorescence exhibit more limited performance. The application of a first-derivative pretreatment significantly improves discrimination for reflectance and transmittance spectra, while its effect on fluorescence data remains moderate. Principal component analysis further suggests a partial structuring of the data according to binder type (acrylic or alkyd) in the fluorescence modes, indicating a binder-related spectral contribution. On the other hand, no particular data structure was observed based on pigment composition. Overall, these results demonstrate that MSP allows a high level of discrimination between visually similar paints when optimized by acquisition mode and pretreatment. This study highlights MSP's strong potential as a key component in integrated forensic paint analysis workflows.
Trending to baseline: A long-term look at the COVID-19 pandemic effects on non-natural deaths in Ontario.
Cullip M, Rosenthal JS, Dmetrichuk JM
Forensic Sci Int · 2026 May · PMID 42241941 · Publisher ↗
INTRODUCTION: Our previous study investigated the acute impact of the COVID-19 pandemic and related public health measures on non-natural deaths in Ontario. This retrospective study evaluates long-term trends, including...
INTRODUCTION: Our previous study investigated the acute impact of the COVID-19 pandemic and related public health measures on non-natural deaths in Ontario. This retrospective study evaluates long-term trends, including 2022-2023 as the post-pandemic phase. METHODS: Homicides, suicides, and accidental deaths (n = 98,209) were extracted from the Office of the Chief Coroner-Ontario Forensic Pathology Service database and crude rates (per 100,000 people) were compared from 2009-2019 (pre-pandemic; A) versus 2020-2021 (pandemic; B) versus 2022 only (post-pandemic year 1; C), 2023 only (post-pandemic year 2; D), and 2022-2023 together (post-pandemic; E). RESULTS: Homicide rates increased during the pandemic (pAB<0.001) and remained elevated in 2022 (pAC<0.001) then decreased to pre-pandemic rates in 2023 (pAD = 0.11). Suicide rates declined, particularly when comparing pandemic years (2020-2021) to the acute pre-pandemic period (R) (2018-2019, pRB<0.001). Rates rose substantially in 2022 (pBC = 0.0042) and decreased to pre-pandemic rates in 2023 (pAD = 0.61). Accidental drug-related deaths increased during the pandemic (pAB<0.001), dropped slightly in 2022 (pBC = 0.021), and then increased in 2023 back to pandemic rates (pBD=0.88). Motor vehicle collision-related deaths declined during the pandemic (pAB<0.001), though rates in 2022 (pAC = 0.26) and 2023 (pAD = 0.87) appear to re-align with pre-pandemic rates. CONCLUSION: Homicide rates increased while suicide and motor vehicle collision-related deaths decreased during the pandemic but appear to be 'trending to baseline', resembling pre-pandemic rates. However, accidental drug-related deaths remain elevated in the post-pandemic years. Ongoing analysis of the pandemic effects on non-natural deaths is required to inform future public health interventions.
A preliminary investigation into the feasibility of using UVC reflection to monitor changes in fingermarks in a research context: The effects of fingermark removal methods and time, substrate and type of fingermark.
Bleay SM, Marsh NP
Forensic Sci Int · 2026 Jun · PMID 42241940 · Publisher ↗
A preliminary study to explore the application of short-wave ultraviolet (UVC) reflection to fingermark visualisation in a research context is reported, consisting of two experiments. The first evaluated the use of UVC r...
A preliminary study to explore the application of short-wave ultraviolet (UVC) reflection to fingermark visualisation in a research context is reported, consisting of two experiments. The first evaluated the use of UVC reflection in the detection of fingermarks after deliberate attempts to remove them from a glass surface, with subsequent comparison of the results of UVC reflection with those obtained from subsequent chemical/physical processing and an interpretation of microstructure obtained using scanning electron microscopy. The second experiment explored the use of UVC reflection in sequential processing routines to establish whether all originally deposited marks are detected by subsequent physical and chemical processes, and whether chemical/physical enhancement always improves mark quality. It was found that UVC reflection was capable of detecting faint traces of fingermarks following deliberate attempts to remove them, but the quality of mark detected by UVC reflection was generally inferior to that developed by subsequent application of a white powder suspension. Scanning electron microscopy revealed some evidence of fingermark residue after all removal methods but in many cases these could not be detected by UVC reflection, although there was sufficient material to interact with white powder suspension. The experiment exploring sequential processing routines showed that UVC reflection could be effective in visualising marks of higher quality than those developed by subsequent enhancement methods, but results were strongly influenced by the substrate marks were deposited on and the composition of the mark. It was concluded that UVC reflection is a useful analytical method to include in fingermark research activities in addition to its potential benefits in casework.
Methodological considerations on repeated measures and sub-LOQ values in passive cannabis hair contamination.
Yu T, Yuan J, Yin H … +3 more , Zhang L, Yi N, Zhao M
Forensic Sci Int · 2026 May · PMID 42235144 · Publisher ↗
Giorgetti et al. report a carefully designed in vivo cross-over experiment showing that brief passive exposures to cannabis or "light cannabis" smoke inside a vehicle can deposit detectable Δ9-tetrahydrocannabinol (Δ9-TH...
Giorgetti et al. report a carefully designed in vivo cross-over experiment showing that brief passive exposures to cannabis or "light cannabis" smoke inside a vehicle can deposit detectable Δ9-tetrahydrocannabinol (Δ9-THC) or cannabidiol (CBD) into hair, even after a validated dichloromethane washing step. Their findings are forensically relevant because washed-hair concentrations sometimes approached or exceeded Society of Hair Testing cut-offs used to infer active use. The work advances beyond in vitro models by using realistic exposure durations. However, two statistical practices warrant further examination: the repeated-measures structure from four volunteers contributing multiple samples was not fully accounted for in primary tests, and values below the limit of quantification were replaced by a constant equal to the limit of detection. These choices may underestimate variability and produce narrow confidence intervals. This discussion reanalyses the authors' tabulated data using linear mixed-effects models and maximum-likelihood Tobit regression. The qualitative conclusions remain consistent, but uncertainty estimates widen materially, suggesting the value of more conservative reporting in small-cohort forensic toxicology studies.
Study on latent sweat fingermark visualization on typical combustible substrates after instantaneous thermal exposure.
Jiang Y, Li Z, Lu Z … +5 more , Yang J, Cao J, Wang X, Jin J, Zhang J
Forensic Sci Int · 2026 May · PMID 42229397 · Publisher ↗
Fingermarks are essential for identification, but the impact of instantaneous high-temperature gas explosion exposure on their visualization remains insufficiently understood, particularly for different combustible subst...
Fingermarks are essential for identification, but the impact of instantaneous high-temperature gas explosion exposure on their visualization remains insufficiently understood, particularly for different combustible substrates and validation through full-scale explosion tests. This research developed a simulation platform for instantaneous thermal exposure (1200°C, 100-1000 ms) and examined six representative substrates: PVC window frames, PVC-coated corrugated and rubber hoses, PC switches, ABS gas alarms, and pine finger-jointed boards. Latent fingermarks were analyzed via macroscopic morphology, optical detection, fluorescent powder dusting and cyanoacrylate (CA) fuming, with quantitatively assessed by the CAST fingermark quality grading system. Results showed substrate thermal stability (pine < PVC < ABS < PC) affected morphology, but visualization success depended more on compatibility between surface state and detection principles.Optical methods were highly sensitive to surface roughening and charring, with effective durations (PC: 400 ms, ABS: 200 ms, PVC: 500 ms, pine: 300 ms) not strictly following thermal stability order. CA fuming failed on charred surfaces due to limited monomer diffusion, showing effective durations of 400 ms for PC, 300 ms for ABS and pine, and 500 ms for PVC. Fluorescent powder exhibited the highest tolerance (PC/ABS: 500 ms; PVC: 700 ms; pine: 600 ms), attributed to strong physical adsorption and fluorescence-based background suppression. Surface topography also proved critical: flat PVC allowed multiple methods, corrugations limited optical/CA efficacy, and ribbed rubber prevented all due to inadequate fingermark transfer.Full-scale explosion tests confirmed the substrate-fingermark visualization method interaction, offering scientific and technical support for fingermark recovery in gas explosion investigations.
Volumetric absorptive microsampling device for forensic Toxicologic screening: A case report as proof-of-concept.
Magny R, Adell J, Labat L … +3 more , Ludes B, Dufayet L, Houzé P
Forensic Sci Int · 2026 May · PMID 42229396 · Publisher ↗
Volumetric absorptive microsampling (VAMS) has emerged as an alternative sampling strategy for toxicological analyses, but its applicability in forensic autopsy settings remains insufficiently documented. In this study,...
Volumetric absorptive microsampling (VAMS) has emerged as an alternative sampling strategy for toxicological analyses, but its applicability in forensic autopsy settings remains insufficiently documented. In this study, we evaluated the use of Mitra™ VAMS devices for qualitative toxicological screening in a real-life medico-legal context, with particular attention to the identification of new psychoactive substances. Multiple biological matrices including peripheral and cardiac blood, urine, bile, and vitreous humor were collected during the autopsy of a 43-year-old male deceased in a suspected chemsex context, using both conventional sampling and Mitra™ devices. Samples were analyzed by liquid chromatography coupled with high-resolution mass spectrometry using both targeted and untargeted screening. Comparable qualitative detection profiles were obtained between conventional samples and Mitra™ microsamples across all matrices. Targeted screening identified several psychoactive substances, including methamphetamine, opioids, and the synthetic cathinone α-PHP. Non-targeted analysis combined with molecular networking enabled the characterization of α-PHP and its phase I and phase II related compounds across matrices, providing a coherent metabolic profile in a forensic context. These results indicate that Mitra™-based microsampling can support qualitative toxicological screening and non-targeted analysis in post-mortem investigations when sample volumes are limited. When integrated into a structured analytical workflow combining targeted and non-targeted HRMS approaches, VAMS shows promise for improving toxicological analyses and supporting forensic identification strategies.
COSA: A consolidated methylation-based prediction panel for body fluid/tissue of origin, smoking status, and chronological age using amplicon-based massively parallel sequencing.
Yang SB, Kim GH, So MH … +2 more , Lee SD, Lee HY
Forensic Sci Int Genet · 2026 May · PMID 42229224 · Publisher ↗
DNA methylation at CpG sites has emerged as a powerful epigenetic biomarker for predicting forensically relevant traits, including chronological age, the biological origin of forensic samples encompassing body fluid and...
DNA methylation at CpG sites has emerged as a powerful epigenetic biomarker for predicting forensically relevant traits, including chronological age, the biological origin of forensic samples encompassing body fluid and tissue sources, and lifestyle-associated factors such as smoking. Existing models for age estimation, body fluid and tissue of origin identification, and smoking inference have demonstrated robust performance, but their reliance on separate assays limits practical application. To address this gap, we developed COSA (a Consolidated prediction panel for Origin, Smoking, and Age), an integrated methylation-based assay implemented through amplicon-based massively parallel sequencing (MPS). COSA consolidates 126 previously reported CpG markers from multiple validated models into 67 amplicons, thereby enabling the simultaneous prediction of body fluid and tissue of origin, smoking status, and chronological age from a single analysis. By unifying these established markers, COSA provides a scalable and streamlined solution for comprehensive forensic epigenetic profiling. The panel comprises three functional modules. First, body fluid identification incorporates 9 CpG markers specific to blood, semen, saliva, menstrual blood, and vaginal fluid, supporting accurate determination of sample origin in forensic framework. Additionally, body fluid and tissue of origin inference extends to internal organs through 18 CpGs targeting blood, liver, skeletal muscle, heart, brain, epidermis, dermis, kidney, and lung. Second, lifestyle inference is supported by 13 CpGs, including the well-characterized cg05575921 locus in the AHRR gene for smoking prediction. Third, age estimation is incorporated through three fluid-specific models optimized for blood, saliva, and semen, which are the fluids most frequently encountered in forensic investigations. Methodological refinements were essential to achieve balanced multiplex amplification. Multiplex PCR for bisulfite-converted DNA is challenged by issues related to primer compatibility and GC-content variation. To overcome this, we implemented a touchdown PCR strategy that improved amplification balance and coverage uniformity across multiple loci. Several primer sets were newly designed or modified to optimize amplicon length and annealing temperature, ensuring robust co-amplification within the 67-amplicon panel. Importantly, using as little as 20 ng of bisulfite-converted DNA, the COSA panel supported inference of biological origin, smoking status, and chronological age. Overall, COSA integrates three major forensic prediction modules, including origin classifiers for body fluids and organ tissues, fluid-specific age estimators, and a smoking-status predictor within a single DNA workflow. This panel represents a practical and scalable tool for forensic laboratories seeking to maximize information yield from limited DNA, advancing the application of epigenetics in human identification and investigative intelligence.
DNA tests for ancestry and phenotype inference applied to the UK Metropolitan Police Operation Minstead: The investigation of serial sex offender Delroy Grant.
Phillips C, Rodriguez A, Gómez-Tato A … +5 more , Álvarez-Dios J, de Cal MC, Salas A, Carracedo Á, Lareu MV
Forensic Sci Int Genet · 2026 Sep · PMID 42225044 · Publisher ↗
SNP analysis in forensic genetics has expanded substantially over the past two decades, particularly for ancestry inference and forensic DNA phenotyping (FDP). However, interpretation of data from such analyses in comple...
SNP analysis in forensic genetics has expanded substantially over the past two decades, particularly for ancestry inference and forensic DNA phenotyping (FDP). However, interpretation of data from such analyses in complex, admixed populations is challenging and, if not carefully contextualized, risks misdirecting criminal investigations. Here we revisit Operation Minstead, a major UK criminal investigation leading to the conviction of serial sex offender Delroy Grant in 2011. In describing our ancestry and FDP analyses of Grant's DNA, we critically examine the role and limitations of early forensic SNP analyses in an operational context. Although DNA was readily available, SNP-based ancestry and phenotyping analyses did not meaningfully advance the investigation. We review the population genetics inferences made by different parties between 2004 and 2008, including reports from a commercial ancestry testing company and independent population genetics expertise, and contrast them with analyses performed by the Forensic Genetics Unit, University of Santiago de Compostela. Our evaluation highlights key methodological issues, including overinterpretation of the inferred co-ancestry proportions of the Minstead suspect, lack of transparency in proprietary SNP panels and reference population data used, and insufficient consideration of within-group variance in admixed populations. We discuss the limitations for inferring common and rare pigmentation patterns in early FDP analyses in individuals with predominantly African genomic backgrounds, and the challenges posed by incomplete marker coverage and limited biological understanding of the expression of pigmentation phenotypes at the time. This case illustrates the risks associated with excessive geographic precision in ancestry inference, especially when likelihoods are modest, and overlap of population variation is substantial. We emphasize the importance of combining information from uniparental markers, X-SNPs, and carefully selected ancestry-informative markers with extreme allele frequency differences, plus the value of likelihood-based frameworks over categorical interpretations. Finally, we discuss how lessons learned from Operation Minstead have informed the development, validation, and interpretation of forensic SNP panels in subsequent years. Overall, this retrospective analysis highlights the need for caution, transparency, and statistical rigor in the forensic application of SNP-based ancestry and phenotyping tests, as well as providing guidance for their careful use in current and future criminal investigations.
Fanniidae (Diptera) of forensic importance, with an identification key for third instar larvae of European species.
Grzywacz A, Pape T
Forensic Sci Int · 2026 May · PMID 42224901 · Publisher ↗
Fanniidae are a dipteran family of growing importance in medico-legal entomology. Several fanniid species are well known to colonise decomposing human remains and animal carcasses, making them potentially valuable indica...
Fanniidae are a dipteran family of growing importance in medico-legal entomology. Several fanniid species are well known to colonise decomposing human remains and animal carcasses, making them potentially valuable indicators for estimating the post-mortem interval (PMI) and reconstructing circumstances of death. In recent years, however, surveys of carrion-associated arthropod assemblages have revealed a much broader diversity of Fanniidae than previously recognised. Despite this, the full range of species of fanniids breeding in cadavers remains insufficiently studied, and identification tools for immature stages are still incomplete. This study provides a key enabling identification of third instar larvae of European species confirmed to colonise human cadavers and the carrion of other animals and a worldwide catalogue of carrion-visiting Fanniidae. For taxa in which larval morphology alone does not allow unambiguous identification, we discuss an integrative approach to taxonomy combining morphological examination with DNA barcoding and species distribution data. The present study fills a major gap in the taxonomy of immature stages of forensically important Diptera and provides a tool allowing for broader application of fanniids in medico-legal investigations.
Why forensic scientists are essential workers.
Houck MM, LaBerge GS
Forensic Sci Int Synerg · 2026 Jun · PMID 42222042 · Full text
Forensic scientists, though crucial, are often overlooked in the "essential worker" discourse. This Perspective argues for their formal recognition as essential government personnel, aligning with federal definitions of...
Forensic scientists, though crucial, are often overlooked in the "essential worker" discourse. This Perspective argues for their formal recognition as essential government personnel, aligning with federal definitions of essential and critical infrastructure workers. Their contributions are vital for timely criminal investigations, successful prosecutions, and protecting the innocent. Despite this, they operate within a "captive profession" under policing, lacking parity in pay, benefits, overtime, and furlough protections compared to sworn officers. The COVID-19 pandemic underscored these issues. While forensic laboratories were mandated to continue operations as part of the justice system's critical infrastructure, forensic staff often face budget cuts and hazardous work conditions while not being acknowledged for doing so. This highlights a systemic undervaluing of forensic science in public safety, where "life and limb" policing often overshadows scientific knowledge and methods that ensure accurate investigations, prevent wrongful convictions, reduce backlogs, and improve long-term public safety. Granting essential worker status to forensic scientists offers significant benefits for attracting and retaining professional personnel leading to sustainable staffing. Beyond mere symbolism, this acknowledgment is fundamental for establishing a sustainable, science-driven public safety infrastructure that values the contributions of technology and science as front-line and essential.
Uncovering mixture inversion: The prevalence of non-handlers as major contributors in forensic DNA evidence.
Roebuck H, van Oorschot RAH, Szkuta B … +2 more , McNevin D, Meakin GE
Forensic Sci Int Genet · 2026 Sep · PMID 42218882 · Publisher ↗
This study presents the first systematic review examining the prevalence of DNA mixture inversion, defined as the occurrence of a major contributor to a DNA profile generated through indirect transfer via an intermediary...
This study presents the first systematic review examining the prevalence of DNA mixture inversion, defined as the occurrence of a major contributor to a DNA profile generated through indirect transfer via an intermediary individual. Following PRISMA guidelines, 45 empirical studies published between 1997 and 2022 were identified as containing relevant data to assess the prevalence of mixture inversion. Analysis of these studies, encompassing 3851 samples, showed that mixture inversion occurred in 1.69% of samples, consistent with previous reports. No significant differences were observed across substrate types. However, handlers classified as low shedders exhibited a higher frequency of mixture inversion compared to intermediate or high shedders. Mixture inversion was more likely following brief handling durations (<30 s) and when handlers had not recently washed their hands. These findings demonstrate that although mixture inversion is relatively uncommon, it may have important implications for interpreting DNA evidence at the activity level.
Application of a short amplicon triallelic SNP panel for parentage analysis of highly degraded DNA.
Xie M, Zheng F, Luo J … +5 more , Fu X, Wang Y, Liu L, Xie Q, Li J
Forensic Sci Int · 2026 May · PMID 42217939 · Publisher ↗
Genetic typing of highly degraded DNA remains one of the most critical challenges in forensic genetics, particularly in parentage analysis, where relationship assessment is needed despite limited genetic information. To...
Genetic typing of highly degraded DNA remains one of the most critical challenges in forensic genetics, particularly in parentage analysis, where relationship assessment is needed despite limited genetic information. To address this, we developed and validated a high efficiency multiplex system comprising 25 triallelic single nucleotide polymorphisms (SNPs) specifically optimized for highly degraded DNA, with all internal amplicons shorter than 110 bp. Validation following SWGDAM guidelines demonstrated a sensitivity threshold of 0.0625 for 100% allele detection rate (ADR), with consistent genotypes obtained down to 0.03125 ng. Performance stability was confirmed through the successful genotyping of artificially degraded DNA (up to 60 min) and formalin fixed paraffin embedded (FFPE) samples (74% average allelic call rate). Population genetic analysis of 230 unrelated individuals from Changsha, China, showed no deviation from Hardy Weinberg equilibrium (HWE), providing an outstanding cumulative matching probability (CMP) of 1.59 × 10 and a cumulative power of exclusion (CPE) of 0.999979. In a validation study of 91 trios, the panel showed 100% concordance with STR based results, achieving a mean cumulative paternity index (CPI) of 5.9 × 10 and resolved potential miscalls caused by a rare primer binding site mutation at rs3857817 through the implementation of degenerate primers. This triallelic SNP panel offers a high performance, cost effective tool for parentage analysis in challenging forensic scenarios involving highly degraded biological evidence.
Evaluating relationship inference from low-quality DNA using a conditional simulation framework.
Jepsen AH, Kampmann ML, Tillmar A … +3 more , Børsting C, Andersen JD, Kling D
Forensic Sci Int Genet · 2026 Sep · PMID 42217278 · Publisher ↗
Inference of genetic relationships from genomic data is central to applications in human, plant, and conservation genetics, with investigative genetic genealogy (IGG) increasingly used in forensic and population studies....
Inference of genetic relationships from genomic data is central to applications in human, plant, and conservation genetics, with investigative genetic genealogy (IGG) increasingly used in forensic and population studies. While high-quality DNA samples enable robust detection of identity-by-descent (IBD) segments, low-quality or low-quantity sources such as telogen hairs pose challenges due to genotyping errors and incomplete genetic data (profiles). In this study, we 1) introduce a conditional simulation framework that generates relatives of varying degrees based on high-quality donor genotypes and allows systematic evaluation of kinship inference under controlled conditions, and 2) demonstrate that short fragments from single telogen hairs provide sufficient SNP data for IGG. Using buccal swabs and telogen hair samples from two donors, we generated whole-genome SNP profiles aided by imputations and compared them with simulated relatives. Despite the poor DNA yield from hair, imputation recovered > 78% of the 1,271,414 target IGG genotypes with > 99% concordance to reference profiles. Genotyping errors were primarily allelic dropouts, which were evenly distributed across the genome. Relationship inference revealed that hair-derived profiles generally supported accurate kinship classification, though elevated error rates in some samples reduced accuracy, particularly for close relatives. Adjusting IBD detection parameters, such as SNP set, error allowances and marker thresholds, improved classification without introducing false positives. In conclusion, our findings introduce a novel conditional simulation framework to quantify the impact of low quality, quantity, or coverage of DNA on kinship inference. We apply the framework to telogen hair samples and show the potential and limitations of single telogen hairs in IGG applications.
EAD-MS/MS-driven intelligent structure prediction and NMR fast structure elucidation framework for nitazene analogs.
Liu CM, Du Y, Huang BY … +3 more , Jia W, Hua ZD, Liao Q
Forensic Sci Int · 2026 May · PMID 42214996 · Publisher ↗
Nitazene analogs, characterized by 2-benzylbenzimidazole core structure, constitute a newly emerging category of potent opioids. As of Jul. 1st, 2025, nitazene analogs have been designated as the third class of new psych...
Nitazene analogs, characterized by 2-benzylbenzimidazole core structure, constitute a newly emerging category of potent opioids. As of Jul. 1st, 2025, nitazene analogs have been designated as the third class of new psychoactive substances (NPS) subject to a generic control, following fentanyl analogs and synthetic cannabinoids in China. This study developed an automated mass spectrometry intelligent elucidation (MSIE) software for nitazene analogs that leverages mass spectrometry fragmentation pathways and characteristic fragment ions derived from 14 nitazene substances under electron-activated dissociation (EAD) conditions. The developed MSIE software facilitates rapid early warning and structure prediction of nitazene analogs. Furthermore, a comprehensive structure confirmation workflow was established based on NMR spectroscopic characteristics, which significantly reduces the time required for structural verification. The integrated mass spectrometry-nuclear magnetic resonance (MS-NMR) platform provides robust technical support for the generic control of nitazene analogs, addressing critical challenges in forensic and pharmaceutical analysis.
Hiring qualified Forensic Investigative Genetic Genealogy (FIGG) practitioners: Recommendations for forensic science and law enforcement agencies.
McLean W, Fahey C, Baker S … +7 more , Ryall A, Kevorkian R, Boyd D, McCarthy A, Collins S, Philipps D, Baney J
Forensic Sci Int Synerg · 2026 Jun · PMID 42211316 · Full text
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Same pattern, different result: Algorithmic inconsistency in breath alcohol testing-case reports.
Olson A, Ramsay C
Forensic Sci Int Synerg · 2026 Jun · PMID 42211315 · Full text
Breath alcohol analyzers employ algorithmic safeguards to identify samples that may be falsely elevated due to mouth alcohol contamination. One such safeguard in the DataMaster DMT (also known as the Intox DMT) is common...
Breath alcohol analyzers employ algorithmic safeguards to identify samples that may be falsely elevated due to mouth alcohol contamination. One such safeguard in the DataMaster DMT (also known as the Intox DMT) is commonly referred to as the 95% rule. Under this criterion, if the final quarter-second average breath alcohol concentration (BrAC) measured during sample delivery is less than 95% of a previous high value recorded during the same sample test, the instrument is expected to generate an Invalid status message. Four cases are presented in which the stated criterion was met, yet the instrument failed to generate an Invalid status message in three of the four cases. The absence of the Invalid status message in the three cases is not explained by any documented alternative criteria or exceptions in the manufacturer's materials or operator training resources. These findings suggest that the 95% rule is either inconsistently applied or subject to additional parameters that govern its implementation. An independent review of the instrument's source code would help clarify the basis for these discrepancies.
Are genetically defined "metapopulations" self-evident in YHRD?
Olsen TOS, Andersen MM, Curran J … +2 more , Krawczak M, Caliebe A
Forensic Sci Int Genet · 2026 Sep · PMID 42208195 · Publisher ↗
In forensic genetics, the evidential value of a match between the Y-chromosomal short tandem repeat (Y-STR) profiles of a trace and a suspect is typically quantified by the frequency of the profile in a population databa...
In forensic genetics, the evidential value of a match between the Y-chromosomal short tandem repeat (Y-STR) profiles of a trace and a suspect is typically quantified by the frequency of the profile in a population database, particularly the Y-chromosomal Haplotype Reference Database (YHRD). However, for this approach of obtaining a 'match probability' to be valid, the database population must be representative of all plausible alternative trace donors in a given case. Since appropriately defining such a 'suspect population' can be difficult, YHRD highlights so-called 'metapopulations' that comprise profiles from different, geographically dispersed populations with presumed shared ancestry. We investigated whether such metapopulations are self-evident in the current version of YHRD. To this end, we performed classical cluster analysis using allele dissimilarity as a measure of pairwise distance between Y-STR profiles. Our analyses revealed only a weak genetic structure in YHRD the extent of which was inversely proportional to the respective marker mutation rate. This suggests that YHRD cannot be divided into clearly distinguishable subgroups based solely on the genetic information it contains, at least not into subgroups that would correspond closely to the metapopulations highlighted in the database itself. If profile frequencies in metapopulations are to continue to be equated with match probabilities, then a clearer definition of metapopulations and a better justification of their use in forensics are needed.
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