Search Results (122)

Background/Objectives: Traditionally, Sanger sequencing was used to characterize reference materials and confirm discordant allele calls from different STR typing kits at the National Institute of Standards and Technology (NIST). Sequencing can also identify genomic variations within polymerase chain reaction (PCR) amplicons containing STRs, particularly variants that result in null alleles and alleles that do not migrate within allele sizing bins provided by kit manufacturers. Methods: Sanger methods are low-throughput, time- and labor-intensive, and require additional procedures for analysis of heterozygous alleles. To address these limitations, a quicker, more straightforward protocol that uses next-generation sequencing (NGS) was developed. Results: This research provides the criteria used to individually sequence thirty-five autosomal STR loci, with PCR primer locations chosen to increase amplicon length and maximize the likelihood of detecting variants in the flanking region. The list of targeted sequences, associated primers, and chromosomal coordinates is also included. Conclusions: By applying NGS technology to forensic samples containing variant alleles, additional information can be obtained about their molecular basis, and this information can be published and shared across the forensic community. The development of this protocol can increase awareness and encourage the integration of NGS technology into forensic laboratories to improve forensic DNA typing for human identification. Full article

Background/Objectives: The widespread adoption of short tandem repeat (STR) marker technology in genetic analysis has led to the collection of substantial STR data from diverse populations. Allele-frequency data provide robust forensic utility and support accurate likelihood ratio calculations, highlighting the importance of regional databases. Methods: The presented study aimed to determine the allelic frequencies and statistical parameters for 16 autosomal genetic STR markers included in the NGM Detect^TM PCR Amplification Kit in a population sample of 220 unrelated individuals from the South-West region of the Republic of Bulgaria. Results: We found that the most polymorphic and informative marker for the Bulgarian population in the southwestern region is SE33, with the next most informative markers being D1S1656, D12S391, D18S51, and FGA. In contrast, D22S1045, D16S539, and D2S441 showed comparatively lower genetic variability and informativeness. At the same time, no deviations from the Hardy–Weinberg equilibrium were observed for the 16 loci studied. Conclusions: This work not only enriches knowledge of the genetic diversity of the Bulgarian population but also provides the Bulgarian and international justice systems with an objective, scientifically sound basis for expert decision-making. Full article

Background: It is essential to recover as much DNA as possible from evidence samples to ensure optimal DNA analysis in forensic casework. However, both DNA collection and purification procedures cause a substantial loss of genetic material. Thus, a large loss of DNA through the pre-PCR procedures, including swabbing and extraction, may significantly affect downstream analysis results. In this study, different cotton swabs and extraction kits used for forensic samples were compared separately. Methods: The recovery of cell-free DNA (control DNA) and cell-bound DNA (blood and saliva) was evaluated using five different extraction kits: Chelex^® 100 Resin, Wizard^® Genomic DNA Purification Kit, QIAamp^® DNA Micro Kit, QIAamp^® DNA Investigator Kit and DNeasy^® Blood & Tissue Kit. The DNA recovery efficiency of the different extraction kits was assessed using real-time quantitative PCR targeting nuclear and mitochondrial DNA targets. In addition, nine cotton swabs from four manufacturers (Selefa^®, Puritan^®, Texwipe^®, and Heinz Herenz) with different production lots were evaluated for DNA quantity and quality using real-time PCR and short tandem repeat (STR) analysis. Results: Overall, large differences in DNA recovery were observed between the different extraction kits. The QIAInvestigator kit demonstrated the highest recovery at low DNA amounts, which is particularly beneficial for minute forensic samples. The swab comparison revealed variations not only in DNA recovery between swab manufacturers but also between lots of the same swab brand, and the DNA quantity was not clearly correlated with downstream DNA profile quality. Conclusions: Our findings emphasise the importance of considering the choice of extraction kit, swab brand and batch-to-batch variation in forensic laboratory procedures, as they may influence DNA recoveries and affect the success rate in forensic casework. Full article

Background/Objectives: Pharmacogenomics (PGx) enables personalized therapy by identifying genetic variants that influence drug response. Despite the advantages of next-generation sequencing (NGS), few clinically validated, guideline-aligned panels comprehensively detect common, rare, and structurally complex pharmacogenetic variants. Methods: We developed and analytically validated Action PharmaKitDx, a targeted NGS panel covering 335 pharmacogenes, including all priority genes recommended by CPIC, DPWG, and CPNDS. Performance was assessed using Coriell HapMap and GeT-RM reference materials across multiple library preparation workflows and Illumina platforms. Clinical feasibility was evaluated in 41 patient samples from diverse specialties. Results were compared with established reference methods, including PCR-based assays, STR analysis, Sanger sequencing, and whole-exome sequencing. Results: Analytical validation: More than 99% of target bases achieved ≥30× coverage. Analytical accuracy, sensitivity, specificity, and positive predictive value exceeded 99.3%, with repeatability and reproducibility >99.7%. Concordance with GeT-RM haplotypes reached 98% after star-allele harmonization. The panel accurately detected complex variants, including CYP2D6 copy-number changes and hybrid alleles. Clinical validation: Full concordance with prior genotyping was observed in clinical samples. Beyond the initial testing indication, each sample harbored a mean of six actionable variants (range 2–10). Thirty-six rare (minor allele frequency <1%) potentially actionable variants were additionally identified. Conclusions: Action PharmaKitDx demonstrates high analytical performance and broad clinical applicability, supporting its implementation as a scalable solution for comprehensive pharmacogenetic testing and precision prescribing. Full article

Background: low-quantity or degraded samples are often studied in forensic genetics. Therefore, it is important to efficiently obtain all the available DNA from the biological sample analyzed to provide the most reliable results. This is particularly challenging in bone marrow processing due to its hydrophobic molecular structure, as for other lipid-rich tissues, especially if rancid. In fact, during adipose tissue decomposition, the putrefaction of fatty acids can in some instances give a compact cerous consistency to the lipidic tissue, hardly susceptible to the nucleic acid extraction mechanisms. According to environmental circumstances, this condition is notably observable in submerged bodies or in putrefied bone marrow. Thus, this study is focused on developing an optimized nucleic acids extraction protocol for putrefied bone marrow. Methods: genetic analyses were performed on putrefied yellow bone marrow collected from 20 human femora recovered from bodies in different decomposition stages. The optimized method was developed by integrating additional steps, reagents and time intervals on a silica-based column commercial kit. This strategy was compared in DNA yield to a standard extraction protocol, represented by the same commercial kit, but following the manufacturer’s directions. Both these strategies were tested in nucleic acid isolation efficiency by performing DNA typing, including real-time PCR quantification, Short Tandem Repeats (STR) amplification and fragments analysis steps. The analytical parameters evaluated were allele count, DNA concentration (ng/µL) and Degradation Index (DI). Results: for allele count and DNA concentration parameters, the optimized protocol showed clear and significant qualitative and quantitative improvements compared with the standard protocol, supporting its potential applicability in forensic casework and laying the foundation for future studies. Conclusions: prior to appropriate laboratory internal validation, the optimized protocol can be used for tough lipid-rich tissues processing without the need to purchase a dedicated system and using a same commercial kit routinely adopted for other forensic genetics matrices. Full article

Autosomal short tandem repeat (STR) markers remain the cornerstone of modern forensic genetics, providing exceptional power for individualization, kinship verification, and reconstruction of complex investigative cases. Over the last decade, the field has undergone a major technological transition from length-based capillary electrophoresis (CE) toward sequence-level characterization using massively parallel sequencing (MPS), enabling detection of internal sequence variants (isoalleles) and flanking-region polymorphisms that substantially increase discriminatory power in many forensic contexts. Although MPS is increasingly adopted in forensic laboratories, implementation remains dependent on infrastructure, cost considerations, validation requirements, and jurisdiction-specific legal frameworks. This review synthesizes the molecular mechanisms underlying STR variability, including replication slippage and mutation processes, and critically evaluates the transition to sequencing-based analysis. Particular attention is given to analytical challenges such as stochastic effects in ultra-low-template DNA and PCR inhibition in degraded samples. Special emphasis is placed on identification of skeletal remains from mass graves and historical contexts, where hierarchical analytical strategies—from mini-STR approaches to MPS-based workflows—enable recovery of highly fragmented DNA. The review also examines the evolution of probabilistic genotyping (PG), highlighting the importance of algorithmic transparency and reproducible analytical frameworks for judicial applications. By integrating technological advances with practical forensic challenges, this review outlines a comprehensive framework for implementing high-resolution STR analysis in contemporary genomic casework. As a narrative synthesis, the conclusions reflect currently available published evidence and acknowledge variability in validation status, implementation practices, and regional forensic infrastructures. Full article

Objective: This study addresses antimicrobial resistance (AMR), a growing public health threat, by evaluating the role of chicken carcasses as possible vehicle for the spread of Escherichia coli O157:H7 and antimicrobial resistance genes (ARGs), with the aim of analyzing the association between bacterial load and the relative abundance of ARGs in samples obtained from an open and an enclosed market in Lima, Peru. Methods: SYBR Green qPCR was used to analyze 28 chicken carcasses from two local markets in the Lima metropolitan area (Enclosed market n = 13, and Open Market n = 15), detecting Escherichia coli O157:H7 and ARGs like bla_CTX-M, bla_TEM, and strA. Results: The bacterial load was higher in the enclosed market (5.062 log CFU/mL) than in the open market (3.875 log CFU/mL). E. coli O157:H7 was detected in 76.9% and 86.6% of samples, with average loads of 1.676 and 1.251 log CFU/mL, respectively. The relative abundance of bla_CTX-M and bla_TEM showed greater dispersion in the open market, whereas strA was more homogeneous in both markets. Significant positive correlation was found between E. coli load and ARGs abundance, stronger in the enclosed market (r = 0.904–0.945) and moderate to high in the open market (r = 0.794–0.920). Conclusions: The results demonstrate a significant correlation between E. coli O157:H7 load and ARGs, highlighting the need for a comprehensive approach within the framework of the “OneHealth” initiative. Full article

Background: The coexistence of antibiotic resistance genes (ARGs) and heavy metals in livestock manure poses critical challenges to vermicomposting technology. Objectives: This study aimed to clarify the zinc (Zn)-driven ARG dynamics over 60-day vermicomposting for livestock manure and provide a reference for taking appropriate measures to reduce the spread of ARGs in the environment. Methods: In a vermicomposting system using Eisenia fetida and treated with varying concentrations of Zn, high-throughput sequencing was employed to analyze microbial succession, while quantitative real-time PCR (qPCR) was performed to track the fluctuation patterns of ARG (tet-, erm-, qnr-, str-, chl-, bla-, mcr-ARGs) and mobile genetic element (MGE, intI1 and intI2) abundances over the 60-day treatment period. Results: Generally, sul- (10⁻³–10⁻¹ copies/16S rRNA), tet- (10⁻³–10⁻² copies/16S rRNA), and str-ARGs (10⁻³–10⁻² copies/16S rRNA) are dominant in dairy manure. Vermicomposting significantly reduced total ARGs (88.62% removal), but Zn stress triggered concentration-dependent shifts. Low Zn (100–250 mg/kg) elevated tet-, erm-, and chl-ARGs via co-selective pressure and disrupted bacterial succession, while high Zn (500–1000 mg/kg) suppressed qnr- and mcr-ARGs but intensified horizontal transfer via cross-resistance. Conclusions: Vermicomposting maintained a greater ARG removal capacity across the Zn gradient (100–1000 mg/kg) than natural composting, proving an effective approach for reducing the threat of antibiotic resistance in bacteria even under high Zn stress. The link between Zn residues and the increased ARG dissemination risks underscores the challenge of co-contaminants, providing essential insights for developing vermicomposting strategies to mitigate ARG risks and ensure sustainable manure management. Full article

Background: Postmortem DNA identification of highly decomposed human remains is often limited by the availability and quality of conventional biological samples. Keratinized tissues, such as fingernails, represent a potentially valuable alternative due to their anatomical resistance to environmental degradation, however, their use as primary biological material for DNA profiling remains underreported in forensic practice. Case presentation: We report a case involving the recovery of a highly decomposed body of a missing woman, in which DNA samples were collected from a fingernail and a tooth. DNA extraction was performed using the PrepFiler Forensic DNA Extraction Kit for the fingernail sample and PrepFiler BTA Forensic DNA Extraction Kit for the tooth sample. No usable DNA profile was obtained from the tooth sample; however, the fingernail sample yielded a complete and high-quality STR profile with successful amplification across all 24 loci (GlobalFiler PCR Amplification Kit). Reference buccal swabs from the presumed biological parents were collected for subsequent kinship analysis. Discussion: Kinship analysis based on allele frequencies in the Croatian population resulted in a combined paternity index (CPI) corresponding to a probability of paternity of 99.99999812%, providing strong genetic support for the proposed identity of the deceased. Notably, this is the first documented forensic case in Croatia in which nail material served as the primary—and ultimately successful—biological sample for postmortem identification. Conclusions: This case highlights the evidentiary value of fingernails as a robust, accessible, and forensically valid DNA source in postmortem identification, particularly in cases of advanced decomposition where conventional biological materials are unavailable or degraded. Further studies involving larger sample sets and diverse postmortem conditions are needed to support the broader implementation of nail material in routine forensic identification workflows, particularly within the Croatian medico-legal context. Full article

Cell line misidentification, first exposed when HeLa cells were shown to contaminate dozens of “unique” cultures, now compromises roughly one in five lines and renders thousands of papers potentially unreliable, propagating unreliable data through hundreds of thousands of citations. The financial fallout is vast with irreproducible research linked to faulty cell stocks costing the United States an estimated $28 billion each year. Today, authentication is rapid, cheap and highly accurate. Modern 24-plex short tandem repeat (STR) kits, analyzed by six-dye capillary electrophoresis and benchmarked against public databases, verify a culture in half a day for less than €40, lowering the probability of mistaken identity to less than 10–15. Complementary SNP panels, low-pass genome sequencing, digital PCR and nascent methylation “age clocks” close remaining blind spots such as aneuploidy or mixed-species co-cultures. Monte-Carlo modeling shows that even at a contamination risk of 0.07% routine STR testing yields a five-year return on investment above 3000% for a mid-size lab. Reflecting this evidence, ANSI/ATCC standards, NIH and Horizon Europe grants, major journals and FDA/EMA guidelines now encourage, recommend, or make authentication mandatory. This review discusses the historical roots and economic losses resulting from cell misidentification and contamination and offers a pragmatic roadmap to prevent working with falsified cell lines. It is further discussed that FAIR-compliant data archiving and integration of STR workflows into laboratory data management systems will allow laboratories to shift from sporadic testing of cell quality to continuous, artificial intelligence-supported assessments. Full article

To systematically investigate how the olfactory system of Bombus terrestris adapts to its social division of labor and reproductive strategies, this study integrated the micromorphology of antennal sensilla and the expression profiles of olfactory receptor (OR) genes from the heads of its three castes (workers, drones, and queens) for a multi-level analysis. Scanning electron microscopy (SEM) revealed that drones possess significantly longer chaetic sensilla (Sch), sensilla trichodea (Str A/B), and sensilla basiconica (Sba A), as well as larger-diameter sensilla coeloconica (Sco) compared to workers and queens, indicating structural and functional specialization for sensitive detection of single key signals (e.g., queen pheromones). In contrast, workers and queens exhibited a more complete composition of sensilla types and a higher sensilla distribution density, suggesting the construction of a perceptual system capable of processing multiple chemical signals simultaneously. RNA-seq combined with qRT-PCR confirmed the significant upregulation of seven OR genes (e.g., BterOR3, BterOR4) in drones, while workers showed upregulation of BterOR3/5/7 accompanied by enrichment of P450 detoxification pathways. Phylogenetic analysis suggested that BterOR5 serves as a conserved co-receptor, and some OR genes may originate from recent duplication events. In summary, distinct differences were observed in the morphological structure and molecular expression of the olfactory system among B. terrestris castes. Drones exhibited structural and gene expression features consistent with specialization in queen pheromone detection, while workers and queens demonstrated sensilla diversity and olfactory receptor expression patterns indicative of a broader response capacity to diverse chemical signals. These findings support the view that the olfactory system has undergone multi-level adaptive evolution driven by social division of labor and reproductive roles. Full article

Background/Objectives The leopard (Panthera pardus), an apex predator listed in CITES Appendix I and classified as Vulnerable by the IUCN, is undergoing severe population declines driven by habitat loss, human–wildlife conflict, and illegal trade. Rapid and reliable species and individual identification is critical for conservation and forensic applications, particularly when analyzing highly processed or degraded seized wildlife products, where morphological identification is often impossible. We aimed to develop and validate a robust multiplex quantitative real-time PCR (qPCR) assay combined with a short tandem repeat (STR) system for the species-specific detection and individual identification of P. pardus. Methods The qPCR assay (Ppar Qplex) was designed to target a mitochondrial Cytochrome b (Cyt b) fragment for species confirmation, a nuclear marker (PLP) for general Feliformia detection and quantification, and an artificial internal positive control (IPC) to monitor PCR inhibition. The assay’s performance was validated for robustness, specificity, sensitivity, repeatability, and reproducibility, utilizing DNA extracted from 30 P. pardus individuals (hair and feces) and tested against 18 related Feliformia species and two outgroups. Individual identification was achieved using a set of 18 STR loci and a sex determination system adapted from previously published Panthera panels. Results Validation demonstrated high specificity for the Ppar Qplex: mitochondrial amplification occurred exclusively in P. pardus samples. The nuclear marker consistently amplified across all 18 tested Feliformia species but not the outgroups. The assay showed high analytical sensitivity, successfully detecting DNA at concentrations as low as 1 pg/µL, with consistent results confirmed across different sample types, replicates, and independent users. Furthermore, the STR multiplex successfully generated 30 unique individual profiles using the 18 polymorphic loci and the sex determination system. Conclusions The combined qPCR assay and STR system provide a fast, sensitive, and highly specific molecular framework for rapid leopard detection, quantification, and individual identification from a wide range of sample types. These tools strengthen forensic capacity to combat wildlife crime and provide critical data to support evidence-based conservation management of P. pardus. P. pardus, an apex predator listed in CITES Appendix I and classified as Vulnerable by the IUCN, is undergoing severe population declines driven by habitat loss, human–wildlife conflict, and illegal trade. Rapid and reliable identification of seized specimens is therefore critical for conservation and forensic applications, mainly when products are highly processed. We developed and validated a multiplex quantitative real-time PCR (qPCR) assay targeting the mitochondrial gene Cytochrome b (Cyt b) for species-specific detection. The assay was tested on verified leopard individuals and validated across 18 Feliformia and two outgroup species (Homo sapiens, Canis lupus familiaris). Analytical performance was assessed through robustness, specificity, sensitivity, repeatability, and reproducibility. Mitochondrial amplification occurred exclusively in leopard samples, while nuclear markers amplified consistently across Feliformia but not in outgroup species. The assay’s limit of DNA detection is 1 pg/µL and produces consistent results across replicates, tested types of samples (hair, feces), and independent users, with internal controls confirming the absence of inhibition. In addition, we present the results of successful individual identification using the set of 18 STR loci and the sex determination system. The developed qPCR and STR systems provide a fast, sensitive, and specific solution for leopard detection and quantification, reinforcing forensic efforts against wildlife crime and supporting conservation of P. pardus. Full article

Background: This study investigated the phenotypic and genotypic antibiotic resistance profiles of 50 Lactic Acid Bacteria (LAB) strains—25 Lactiplantibacillus plantarum and 25 Lacticaseibacillus paracasei—isolated from traditional Sardinian fermented foods of animal origin. Methods: The sensitivity of the isolates to antibiotics such as β-lactams, tetracyclines, aminoglycosides, macrolides, phenicols, and glycopeptides was initially assessed using disc diffusion and minimum inhibitory concentration (MIC) tests. Subsequently, PCR analyses were performed on both genomic DNA and plasmid DNA to detect blaZ, tet(W), strA, aac(6′)-Ie–aph(2″)-Ia, and vanX genes associated with resistance to ampicillin, tetracycline, streptomycin, gentamicin, and vancomycin. Results: The analysis revealed that L. plantarum strains frequently carried the tet(W) gene on the chromosome and strA on plasmids, while vanX was detected in most strains as a chromosomal determinant. By contrast, L. paracasei strains exhibited a predominantly plasmid-mediated distribution of resistance genes. For example, strA, aac(6′)-Ie–aph(2″)-Ia and blaZ were often found on plasmids, whereas vanX remained chromosomally encoded. Phenotypic assays confirmed high intrinsic resistance to vancomycin in both species, with L. plantarum showing a higher overall frequency and diversity of resistant phenotypes compared to L. paracasei. Conclusions: The co-occurrence of multiple resistance determinants, including plasmid-encoded ones, in most strains suggests that even autochthonous isolates from artisanal products may represent potential reservoirs for transmissible resistance genes. Full article

Objectives: To investigate the phenotypic and genotypic changes of Acinetobacter baumannii collected from the tertiary oncology setting in Lithuania. Methods:A. baumannii isolates (n = 61) were collected in the years 2013–2014 (n = 28) and 2017–2019 (n = 33) from a tertiary care cancer center in Lithuania. Antimicrobial susceptibility was determined according to EUCAST and for piperacillin/tazobactam and cefepime, according to CLSI guidelines. PCR, pulsed-field gel-electrophoresis, and multi-locus sequence typing were used for resistance gene detection and genotyping. The biofilm formation ability was determined by a microtiter plate assay. Results: Of 61 A. baumannii isolates obtained, 84% (51/61) and 71% (43/61) were multi-(MDR) and extensively (XDR) drug-resistant, respectively. Carbapenem-resistant isolates comprised 77% (47/61); of these, 92% (43/47) harbored genes encoding the OXA-23-like, and 4% (2/47) OXA-24-like carbapenemases. All isolates were susceptible to colistin. Genotyping analysis revealed six groups with the highest prevalence of international clones 1 (IC1) and 2 (IC2), which dominated during 2013–2014 and 2017–2019, respectively. Notably, the A. baumannii diversity increased in 2017–2019 with the emergence of 3-LST groups G4, G8, G12, and G14, which included isolates of ST276, ST78, ST1463, and ST1336 sequence types, respectively. The IC1 and IC2 isolates displayed characteristic gene profiles aacC1, aacC2, aphA6, sul1, and armA, strA-strB, bla_TEM, respectively, whereas isolates from other groups had lesser resistance gene content. Isolates from IC2, G12, and G14 groups were strong biofilm producers; IC1, G4, and G8 isolates displayed no/weak biofilm formation capacity. Conclusions: A. baumannii from the cancer center showed a high prevalence of MDR and XDR phenotypes. Clonal dominance and diversity changed during the surveillance periods with the replacement of IC1 by IC2 clone isolates and the emergence of higher clonal diversity of isolates with stronger biofilm-forming capacity. The observed changes indicate a concerning trend of the establishment of a more virulent A. baumannii in the cancer setting. Full article

Background/Objectives: Formalin-fixed paraffin-embedded (FFPE) tissues are sometimes the only DNA source for forensic applications. The quantity and integrity of the DNA extracted from these samples depend on multiple factors. In this work, we analyzed, for the first time, whether Masson’s trichrome (MT) staining alters the results of genetic profiles obtained from DNA extracted from FFPE tissue sections. Methods: Three pairs of sections from the year 2024 and three pairs from the year 2001 were analyzed. Each pair consisted of serial sections, one stained with hematoxylin and eosin and the other with MT. DNA was extracted using the PrepFiler Express BTA™ Forensic DNA Extraction Kit and quantified by real-time PCR using the Quantifiler™ HP DNA Quantification Kit. DNA samples were processed for short tandem repeat (STR) profiling using the GlobalFiler™ PCR Amplification Kit. The amplified alleles were separated and analyzed using an ABI PRISM^® 3500 genetic analyzer. Results: All MT-stained samples showed deficiency in most or all of the parameters assessed: DNA yield, degradation index, number of alleles detected, random match probability value, and intensity of the electropherogram peaks. In fact, DNA could not even be quantified in the samples processed in 2001. Conclusions: These results could be due to the large number of acids used in MT staining, which cause chemical modification and hydrolysis of DNA, affecting the success of PCR-based methods used subsequently. In conclusion, DNA obtained from MT-stained FFPE tissue sections may be highly degraded and should therefore be used with great caution in forensic settings. Full article