Forensic Science International: Genetics

The geographical and familial origins of Christopher Columbus have remained a subject of intense historiographical debate for over five centuries. Despite numerous hypotheses, empirical genetic evidence capable of resolving his ancestral history or place of birth has been absent from the literature until now. This study presents the third stage of the first forensic genetic analysis performed on skeletal remains belonging to several direct descendants of Columbus, spanning the 16th to 18th centuries. By applying Massively Parallel Sequencing (MPS) to analyse autosomal, X- and Y- chromosome DNA markers, and integrating the results with multidisciplinary evidence from historical, genealogical, archaeological, and anthropological research implicated in this project, the identification of several individuals founded in the Crypt of Santa Maria de Gracia located in Gelves (Sevilla, Spain) has been achieved. The analysis of their biological relatedness enabled the reconstruction of kinship networks among the individuals interred in the crypt, which, when interpreted in the context of documented genealogical lineages, provides indirect but consistent evidence pointing toward the debated origin of the discoverer.

In wildlife forensic practice, species identification and estimation of the Minimum Number of Individuals (MNI) for highly processed specimens have long relied on weight-based conversion methods, which may result in underestimation of the number of individuals involved in a case. Focusing on confiscated casque products of the helmeted hornbill (Rhinoplax vigil), this study combines macroscopic morphological examination with mitochondrial DNA barcoding (16S rRNA, COI, and Cytb) to explore a more robust approach for individual quantification. The results demonstrate that the conventional "weight-based" approach overlooks critical biological information contained in anatomical structures and cannot accurately reflect the actual number of individuals involved. Based on this, we propose an anatomy-based criterion centered on the principle of structural uniqueness: specimens retaining biologically unique beak or casque structures should be directly assigned to a single individual, whereas weight-based estimation should only be applied when original anatomical features are entirely absent. In addition, considering material loss during processing, we propose approximately 85 g as a reference threshold for estimating the number of individuals in heavily processed solid casque products. This approach improves the scientific rigor and accuracy of forensic identification and provides reliable technical support for the conviction, sentencing, and law enforcement of wildlife trafficking cases involving helmeted hornbill and other endangered species.

The early evolutionary history of modern domestic horses (Equus caballus/E. ferus caballus), known as the DOM2 lineage, is well documented due to numerous archaeological and ancient DNA (aDNA) studies. Although many uncertainties remain in the domestication timeline, current evidence suggests that the domestication of modern horses began in the Pontic-Caspian steppe at least [~]2700 BCE (before common era), or even earlier. However, it is not known how long remnant wild horse populations survived or when domestic horses were introduced into Northern Europe. In this study, we review the current knowledge of horse domestication, focusing on Northern Europe. We analysed prehistoric horses from western Russia to assess the body sizes of wild horses from the Ivanovskaya site (5900-3800 BCE) in the Pontic-Caspian steppe, and the body weight of one Lithuanian wild horse (4000-3800 BCE). Additionally, we analysed body sizes of Late Bronze Age-Early Roman Age horses (1100 BCE-300 CE; common era) and re-analysed body sizes and estimated rider weights of historic domestic horses from Lithuania (100-1400 CE). We searched for pathological changes and signs of bit wear indicative of bridling. Furthermore, we investigated maternal genetic diversity by sequencing ancient mitochondrial DNA. We found that wild horses from Ivanovskaya were intermediate in body size between earlier and more recent horses of the Eurasian Steppe, and that the Lithuanian wild horse weighed only [~]270 kg and Late Bronze Age-Early Roman Age horses 200-300 kg. Lithuanian domestic horses were pony-sized (< 130 cm on average). Bit wear was confirmed on one tooth, the oldest domestic horse in Lithuania (799-570 cal BCE). Another tooth showed signs of the Equine Odontoclastic Tooth Resorption and Hypercementosis (EOTRH) condition. Mitochondrial DNA was successfully amplified from one Ivanovskaya wild horse along with 25 other ancient samples, including Lithuanias oldest domestic horse. mtDNA diversity was high, revealing several maternal lineages.

Characterized by the earliest use of pottery, the Jomon culture was a unique Neolithic culture that spread throughout the Japanese Archipelago. Previous archaeological evidence suggests that Jomon hunter-gatherers colonized the southernmost islands, the Ryukyu Archipelago, by approximately 7,000 years before present (YBP). However, genetic characteristics of the Ryukyu Jomon population and its contribution to the modern population have not been elucidated yet. In this study, we newly sequenced 273 modern and 25 ancient (6,700-900 YBP) whole genomes collected across the Ryukyu Archipelago. Our analysis demonstrated a genetic differentiation between the Hondo (Japanese mainland) and Ryukyu Jomon, dating back to [~]6,900 YBP. After the divergence from the Hondo Jomon, the Ryukyu Jomon experienced severe bottlenecks, with an effective population size of [~]2,000. Admixture between the Ryukyu Jomon and migrants from the historic Hondo population occurred [~]1,000 YBP, which corresponds to the widespread adoption of iron tools and agriculture in the Central Ryukyus. Different demographic histories between modern Hondo and Ryukyu populations resulted in different rates of Jomon ancestry in these populations. By providing a new perspective on the peopling of the Ryukyu Archipelago, this study significantly enhances our understanding of cultural transitions in the region.

BackgroundThe World Health Organization (WHO) has raised concerns over increasing Pfhrp2/3 deletions, undermining the sensitivity of Pfhrp2-based rapid diagnostic tests (RDTs). Close monitoring of the population and a change in diagnostic methods are recommended if the prevalence of parasites with Pfhrp2/3 deletions exceeds 5%. In high transmission settings, accurate estimates are hampered by the frequent occurrence of mixed-clone infections (multiplicity of infection; MOI). Objective and MethodsIf parasites with and without deletions are present in an infection, standard molecular assays cannot detect the presence of the former. To accurately estimate frequencies of haplotypes with Pfhrp2/3 deletions in the presence of mixed infections, a novel statistical model that combines genetic/molecular information from Pfhrp2/3 with that from neutral markers is introduced. Maximum-likelihood estimates (MLEs) are obtained for haplotype frequencies characterized by markers at Phrp2/3 loci and loci for neutral markers. The expectation-maximization algorithm is used to derive the MLEs. The adequacy of the method (precision and accuracy) is assessed by numerical simulations. ResultsThe method was applied to an active surveillance study conducted in a tribal community in Jagdalpur, India, which enrolled febrile community members (n = 432) between October and November 2021. Four markers each at Pfhrp2 and Pfhrp3 are combined with one marker each at Pfmsp1 (which encodes P. falciparum merozoite surface protein 1) and Pfmsp2. Data from a total of 117 patients who had both P. falciparum infections and genetic information for the molecular markers underwent further analysis with the novel statistical method. ConclusionResults indicate that this novel method has promising statistical properties (asymptotic and in finite samples) and can be readily applied to real-world situations. A stable implementation of the method in R is provided. This novel approach enables accurate estimation of Pfhrp2/3 deletion frequencies in complex P. falciparum infections, addressing a key limitation of current molecular surveillance methods. Author summaryPlasmodium falciparum (Pf) causes the most severe form of human malaria, accounting for over 90% of cases. Rapid diagnostic tests (RDTs) have become a cornerstone of malaria control. These RDTs detect Pf-specific antigens in a blood drop. HRP2/3 emerged as the best antigen for such tests because it is Pf-specific and expressed in abundance. However, some parasites lack the genes that code for HRP2/3 proteins. If parasites in an infection have such gene deletions, RDT results can be false negative. The WHO considers the containment of such deletions a public health priority and recommends monitoring their prevalence. The detection of HRP deletions is challenging if parasites with and without deletions co-occur in infections because standard molecular assays cannot detect deletions in this situation. To overcome this challenge, we introduce a novel statistical method to estimate the frequency distribution of parasite variants with deletions. The method combines information from neutral molecular markers and from HRP-related markers to correct for unobservable information. Here we provide a derivation of the statistical model, a stable implementation, and test its statistical properties with synthetic and real data, thereby showing that our method is well-suited for the underlying problem.

Multiplexing samples in long-read sequencing with Oxford Nanopore Next Generation Sequencing Technology (ONT) by ligating specific native barcodes to individual DNA samples enables significant increases of high throughput sequencing combined with a significant reduction of sequencing costs. However, this advantage carries the risk of barcode misassignment / crosstalk. Employing ONT multiplex sequencing with samples, we observed misassigned barcodes so called barcode crosstalk, after ONT library preparation according to the standard protocol, particularly in samples with low input DNA concentrations. We assumed that these barcode misassignments are largely due to misligation of remaining native barcodes during subsequent the subsequent sequencing adapter ligation. To systematically investigate and quantify barcode crosstalk, genomic DNA (gDNA) from four bacterial type strains with different DNA input concentrations was prepared using three protocols for library preparation: the Nanopore standard protocol (protocol A: version valid until July 2, 2025) the new Nanopore protocol (protocol B: version from July 2, 2025), and an in house protocol with pooling of the barcoded samples only after the sequencing adapter ligation step (protocol C: in house). All samples were sequenced on a Nanopore PromethIon device. The results clearly showed that the use of protocol A resulted in a pronounced barcode crosstalk especially detectable in samples with low DNA input concentrations (up to 2.4% misassigned reads). The ONT adjustment in protocol B (altered washing buffer vs. protocol A) significantly alleviated the barcode crosstalk to below 0.01%, whereas protocol C eliminated barcode crosstalk virtually completely. These observations emphasize that sequencing results obtained with older ONT native barcoding protocol variants should be critically reviewed. The newer ONT barcoding protocol is preferable for sequencing, but it does not completely eliminate the barcode crosstalk effect. In conclusion, for low DNA input and high accuracy sequencing, protocol C is recommended.

BackgroundDNA polymerase activity assays are required for enzyme quality control in biotechnology and diagnostics, but standard methods rely on specialist reagents, radioactivity and other hazardous materials, or real-time PCR instruments that are not widely accessible in resource-limited settings. This constrains local production of high quality, validated reagents and increases dependence on imported enzymes. MethodsBased on experiences derived from partnerships with scientists in several low and middle-income countries (LMICs) and stakeholder consultations, we adapted a commercial EvaGreen-based fluorometric DNA polymerase activity assay for isothermal operation using minimal equipment. Assay conditions were optimized using Design of Experiments (DOE) methodology, varying temperature, reaction volume, and MgCl2 concentration. To address reagent cost and supply-chain constraints, we developed detailed protocols for in-house synthesis of the off-patent AOAO-12 DNA dye (sold commercially as EvaGreen) and generation of single-stranded DNA templates via asymmetric PCR. ResultsOptimized isothermal assay conditions (40{degrees}C, 7.75 mM MgCl2) reliably quantified activity across multiple DNA polymerase families. In-house synthesized AOAO-12 dye exhibited comparable DNA-binding performance to commercial alternatives (R{superscript 2} = 0.95), reducing costs by more than an order of magnitude when normalized to working concentrations, enabling assay costs of approximately {pound}0.001 per reaction. The assay is effective across multiple polymerases (Bst-LF, OpenVent, Taq, Q5) and is compatible with both plate readers and qByte, a low-cost, open-source fluorometric device. ConclusionsThis stakeholder-informed assay provides an accessible, cost-effective solution for DNA polymerase quality control in resource-limited settings. The combination of optimized commercial protocols and in-house reagent synthesis offers flexibility for different resource contexts, potentially improving access to molecular biology tools globally.

Global quantification of DNA cytosine modifications, including 5-methylcytosine (5-mC) and 5-hydroxymethylcytosine (5-hmC), is important for understanding cancer biology, though established methods require multi-step workflows and costly instrumentation. Here we show that attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy combined with regression modelling enables rapid, label-free, and non-destructive quantification of both modifications from DNA samples. Using Adenomatous Polyposis Coli (APC) promoter DNA standards spanning 0-100% modification, we identified modification-sensitive spectral features and observed that 5-hmC produces greater spectral changes than 5-mC. A univariate peak-ratio approach yielded strong linearity for both modifications (R2 = 0.97), while partial least squares regression (PLSR) improved quantification accuracy to R2 = 0.99 (RMSE = 2.6%) for 5-hmC and R2 = 0.97 (RMSE = 5.7%) for 5-mC. In composite mixtures containing all three cytosine states, 5-hmC remained highly quantifiable (R2 = 0.97; RMSE = 5.1%), while 5-mC accuracy decreased (R2 = 0.90; RMSE = 9.6%), consistent with the greater spectral distinctiveness secondary to the hydroxymethyl group. Transferability was assessed using circulating tumour DNA (ctDNA), short cell-free DNA fragments shed from tumour cells into the bloodstream, comprising multiplexed reference material spanning seven genomic regions and a polydisperse fragment-length distribution (155-220 bp). After domain adaptation between synthetic and ctDNA spectra, we obtained a quantitative methylation calibration with R2 = 0.98 and RMSE = 5.2% under cross-validation. These results support ATR-FTIR spectroscopy as a viable platform for global cytosine modification quantification and establish proof-of-concept applicability to ctDNA analysis.

BackgroundConventional models of human ribosomal DNA (rDNA) array organization have historically depended on transcription-centric boundaries, partitioning the unit into a [~]13 kb rDNA transcription region and a monolithic [~]31 kb intergenic spacer (IGS). While our previous identification of Duplication Segment Units (DSUs) mapped these arrays based on an intuitive analysis of the microsatellite density landscape of the complete reference human genome, our present deep mining of this landscape has revealed a more accurate rDNA Gene Unit Pattern. Methods & ResultsIn this study, we conducted a deep mining analysis of our previously established microsatellite density landscape of the T2T-CHM13 assembly, focusing specifically on nucleolar organizing regions (NORs). We suggest a more accurate rDNA Gene Unit Pattern containing a (CTTT)n microsatellite aggregation ahead of the rDNA gene and a (CT)n microsatellite aggregation behind the gene, rather than a pattern featuring an IGS region inserted between two rDNA genes. ConclusionsA correct rDNA gene pattern of the human genome probably includes a (CTTT)n microsatellite aggregation ahead of the gene and a (CT)n microsatellite aggregation behind it, which possibly constitute cis- and trans-regulating regions; the (CTTT)n and (CT)n microsatellite aggregations may provide two different local stable DNA structures for regulatory protein binding.

This study was aimed at characterizing the physicochemical analysis of stingless bees honey (SBH) in the Wonchi district, Southwest Shewa Zone, Ethiopia. In this study, a total of 30 stingless bees honey samples were collected from Damu Dagele, Fite Wato, and Warabu Messe sites from underground soils through an excavation of natural nests. Physicochemical characterization of properties and proximate analysis of the honey were performed. The result showed a total mean of 20.12{+/-}1.14% moisture content, 8.62{+/-}2.73 meq./kg free acidity, 1.8{+/-}0.52 mS/cm electrical conductivity, 3.39{+/-}0.32 pH, 40.52{+/-}6.61 mg/kg HMF, 0.83{+/-}0.33% ash, 0.56{+/-}0.25% protein, 0.56{+/-}0.24% fat, and 0.59{+/-}0.23% WISC for physicochemical properties of stingless bees honey. Among sugar profiles of SBH, fructose constituted the highest proportion at 18.87 g per 100 g (53.87%), while sucrose exhibited the lowest concentration at 5 g per 100 g (14.33%). The result showed that the highest constituted mean of mineral composition was observed with potassium (K) of 16.64{+/-}0.257 mg/kg, while magnesium (Mg) showed the lowest concentration of 3.48{+/-}0.17 mg/kg. A substantial correlation was observed between K and Mg, with a correlation coefficient of 0.72 and 0.72, and similarly between K and Calcium (Ca); the correlation was highly significant, exhibiting a correlation coefficient of 0.65. Furthermore, the correlation between fatty and other physicochemical and proximate analyses showed very insignificant correlations. In general, this study showed that the SBH produced in the current study area has good physicochemical properties and moisture and contains high-quality honey, which may help its traditional medicinal uses. The findings of the study further suggests the potentiality of the area for quality honey, and to easily locate priority areas for stingless bee conservation, further detailed studies of other stingless species honey medicinal values are recommended.

Endocavity ultrasound transducers, particularly transvaginal ultrasound (TVUS) probes, contain intricate structures such as notches, grooves, lens surfaces, and handle edges that are highly susceptible to microbial contamination yet difficult to disinfect using conventional high-level disinfection (HLD) methods. This study evaluated the efficacy of a novel ultraviolet-C light-emitting diode (UV-C LED) HLD system in eliminating microbial contamination from these complex probe surfaces. Two TVUS probes were sampled from predefined high-risk regions before and after disinfection following clinical use. Probe A was sampled at the top and bottom notches and both sides of the handle, while Probe B was assessed at the lens, edges, and bent groove regions. Microbial contamination was quantified using swab sampling, culture on agar plates, and identification via MALDI-TOF. Environmental sampling of examination and disinfection rooms was also performed. To assess this system robustness, probe sites were repeatedly inoculated with Bacillus subtilis spores and evaluated following UV-C treatment. Before UV-C treatment, contamination rates ranged from 25% to 57% across sampled regions, with microbial loads reaching up to 3.9 log CFU. Identified organisms included Staphylococcus epidermidis, Pseudomonas koreensis, Bacillus cereus, and Propionibacterium spp. Probe sheaths were also predominantly contaminated with Staphylococcus epidermidis., with counts reaching up to 4.3 log CFU, Environmental sampling revealed diverse microbiota, with higher contamination levels in examination rooms compared to disinfection areas. Following 90 seconds of UV-C exposure, no microbial growth was detected on any sampled site, indicating 100% decontamination. Additionally, UV-C treatment achieved >6.7 log reduction of B. subtilis spores across all tested regions. These findings demonstrate that UV-C LED technology provides rapid, effective, and consistent high-level disinfection of complex TVUS probe surfaces, supporting its potential as a rapid and reliable disinfection modality in clinical setting.

A compact, in-house developed ultraviolet germicidal irradiation (UVGI) system adaptable to static, mobile, or robotic platforms was developed for the effective sterilization of bacteria and fungi using a wireless mode of operation. Under controlled laboratory conditions, its efficacy was evaluated against three representative biofilm-forming pathogens: Bacillus subtilis (Gram-positive, spore-forming, motile bacterium), Escherichia coli K12 (Gram-negative, non-spore-forming, non-motile bacterium), and Candida albicans M-207 (multi-drug-resistant, clinical yeast isolate). Microbial viability following UVGI exposure was assessed using colony-forming unit (CFU) and MTT assays, and morphological alterations were characterized by scanning electron microscopy (SEM). Cultures were exposed to UV-C radiation at distances of 1-5 m for 15-90 min. CFU assay demonstrated 100% kill of all tested organisms at 1 m and 15 min, corresponding to doses of 600.3, 576 & 697.5 mJ/cm{superscript 2}. Although MTT assays indicated residual metabolic activity under the same conditions, CFU results confirmed that surviving cells were unable to proliferate, highlighting the robustness of UV treatment for long-term inactivation. SEM confirmed distinct morphological alterations such as complete destruction of extracellular matrix & reduction in number of cells indicating cell death with increase in UV dose as compared to controls. A dose & time-dependent inactivation of biofilm-forming bacteria & fungi was observed on exposure to UVGI. Therefore, this pilot study validates the effectiveness of the newly developed UVGI surface sterilizer against biofilm-forming bacterial and fungal pathogens. Overall, the system demonstrates proof-of-concept efficacy under laboratory conditions and holds strong potential for future development and validation in hospitals and other contaminated public spaces. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=91 SRC="FIGDIR/small/715580v1_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@150cefcorg.highwire.dtl.DTLVardef@450831org.highwire.dtl.DTLVardef@1cfd6borg.highwire.dtl.DTLVardef@1419ba8_HPS_FORMAT_FIGEXP M_FIG C_FIG IMPORTANCEMicroorganisms that form biofilms on surfaces are difficult to eliminate and contribute to the spread of infections in healthcare and indoor environments. There is a need for practical, easy-to-use disinfection technologies that can effectively reduce such contamination. In this study, we developed a compact, in-house, wireless UV-C disinfection system designed for flexible operation across different surface types. The system was evaluated under controlled laboratory conditions using representative biofilm-forming bacterial and fungal pathogens. Our findings show that the system can effectively reduce microbial contamination, demonstrating proof-of-concept efficacy. This work highlights the potential of accessible, non-chemical UV-based technologies and supports their further validation for applications in real-world disinfection settings.

Alleles of ASIP gene (Agouti locus) in dogs determine a wide spectrum of coat colors, from red to black. Gain-of-function Ay allele is the most dominant in the range of known ASIP mutations: when all other genes affecting coat pigmentation are intact, presence of Ay allele results in red coat color. Loss-of-function a allele is the most recessive allele of this gene. When homozygous, it gives black coat color. Usually, dogs with Ay/a genotype have red coat, because a single copy of Ay allele is sufficient to fully compensate for the non-functional allele a, implying the complete dominance in this pair of alleles. However exceptions are known. In the Hungarian Puli breed there is a specific coat pigmentation type called fako. We investigated the genetic composition of fako dogs and found evidence that the dominance of the Ay allele over the a allele may be incomplete in these dogs. Analysis of the MC1R gene that interacts with ASIP in the hair pigmentation genetic cascade allowed us to find the variants that may be responsible for the incomplete dominance of Ay allele over a allele in Hungarian Puli dogs.

Whole-genome sequencing (WGS) enables comprehensive analysis of tumour genomes, but its use in formalin-fixed paraffin-embedded (FFPE) samples is limited by DNA fragmentation and low yields. Whole-genome amplification (WGA) methods such as multiple displacement amplification (MDA) can boost DNA availability but distort copy-number alteration (CNA) profiles. DNA ligation-mediated MDA (DLMDA) mitigates this bias by reconstituting fragmented templates, yet its performance in FFPE-derived DNA remains uncertain. We compared paired DLMDA pre-amplified (2h, 8h) and non-pre-amplified FFPE prostate tumour samples from 22 archival blocks (5, 15 and 20 years old). DLMDA increased DNA yield by 42- to 86-fold, with global CNA patterns largely preserved. However, DLMDA significantly reduced the number of detected CNA deletions and amplifications. These effects were independent of both block age and reaction time. CNA dropouts were randomly distributed across the genome, indicating that DLMDA does not introduce regional bias. Our results show that DLMDA enables robust DNA yield recovery and avoids false-positive CNA artefacts, but at the cost of reduced CNA sensitivity. While suitable for CNA screening pipelines through WGS, further improvements are required to minimise the false-negative risk and improve the techniques sensitivity for FFPE-based genomics.

IntroductionRetinoids are bioactive vitamin A derivatives that regulate cellular differentiation and gene expression, yet their reliable quantification remains challenging due to low abundance, structural isomerism, and sensitivity to ionization conditions while handling. ObjectivesIn this study, we performed a systematic optimization of liquid chromatography-mass spectrometry (LC-MS)-based detection of retinoids across tissues and biofluids. MethodsChromatographic separation, adduct formation, ionization parameters, fragmentation behavior, and extraction procedures were evaluated in an integrated workflow. ResultsChromatographic conditions influenced not only retention time but also the ionic species detected, affecting precursor selection for MS{superscript 2} analysis. Retinoids exhibited compound-dependent responses to electrospray ionization and collision energy, requiring tailored acquisition parameters. Extraction experiments demonstrated differential recovery among retinoid classes and revealed matrix-dependent behavior, indicating that protocols used for tissues cannot be directly transferred to low-abundance biofluids. Using optimized conditions, retinoids were detected in mouse cerebrospinal fluid (CSF) at concentrations approaching the analytical detection limit, where MS{superscript 2} confirmation was necessary for reliable identification. ConclusionTogether, our results provide a framework for reproducible retinoid profiling across biological matrices and enables comparative studies of retinoid biology in low-volume and low-abundance biofluids.

Plasmodium vivax transmission from humans to mosquitoes depends on the density of gametocytes that in turn depends on asexual parasite replication and gametocyte commitment. These processes are often analyzed separately, despite being biologically linked and measured with substantial uncertainty. We used a joint Bayesian latent-variable model to simultaneously analyze parasite density, gametocyte density, and mosquito infectivity while accounting for measurement error and propagating uncertainty across linked processes. The model was applied to individual-level data from three P. vivax transmission studies conducted in Ethiopia (n = 455). A tenfold increase in gametocyte density was associated with more than a twofold increase in the odds of mosquito infection (odds ratio [OR] = 2.32, 95% credible interval [CrI]: 2.12-2.54). Asexual parasite density was also positively associated with infectivity after accounting for gametocyte density (OR = 1.74, 95% CrI: 1.60-1.90), and inclusion of parasite density improved predictive performance. Pathway decomposition within the joint model indicated that approximately 41% of the parasite-infectivity association operated through gametocyte density. Increasing age was associated with lower asexual parasite density but higher gametocyte density, resulting in minimal overall association with infectivity. Predicted infection probability increased sigmoidally with gametocyte density, remaining low at lower densities before increasing sharply and approaching a plateau at higher densities. Gametocyte density produced the largest predicted changes in the proportion of infected mosquitoes, while asexual parasite density added predictive information not fully captured by measured gametocyte density alone. This approach links molecular parasite measurements with mosquito infection risk while accounting for measurement uncertainty and provides an interpretable framework for studying the P. vivax infectious reservoir. Author SummaryMalaria transmission occurs when mosquitoes ingest sexual-stage parasites, called gametocytes, during a blood meal. In Plasmodium vivax infections, human-to-mosquito transmission depends on linked biological stages, including asexual parasite replication, gametocyte production, and mosquito infection. These processes are closely connected and often measured with uncertainty, making them difficult to study using standard approaches that analyze them separately. In this study, we applied a joint Bayesian model that analyzes parasite density, gametocyte density, and mosquito infectivity together while accounting for uncertainty in laboratory measurements. Using data from three studies in Ethiopia, we quantified how parasite density, gametocyte density, and host characteristics relate to mosquito infection. The analysis showed that measured gametocyte density alone did not fully explain variation in infectivity, and that asexual parasite density provided additional predictive information. We also found that age was associated differently with asexual parasite and gametocyte densities, resulting in little overall association with infectivity. This approach helps link molecular parasite measurements with transmission outcomes and improves understanding of the P. vivax infectious reservoir in endemic settings.

GT-seq (Genotyping-in-Thousands by Sequencing) is widely used for high-throughput amplicon genotyping, but most analytical pipelines focus on single SNPs or rely on alignment-based variant calling. Here we present an alignment-free approach for microhaplotype genotyping that leverages the high read depth and low error rates typical of paired-end Illumina and Element sequencing. The pipeline first identifies primer-bounded reads and resolves paired-end sequences into complete amplicon sequences. Within each sample and locus, unique sequences are ranked by read abundance and the top one or two sequences are retained as candidate diploid alleles. These alleles are aggregated across samples to construct a catalog of unique haplotypes for each locus. In a second pass, reads are assigned to catalog haplotypes by exact sequence matching to produce diploid genotypes. Finally, catalog haplotype sequences are positionally compared to identify phased SNP and collapsed indel variation, generating compact microhaplotype representations suitable for population genetic analysis. This approach enables robust, alignment-free microhaplotype inference directly from high-depth amplicon sequencing data.

The Medieval Ottonian dynasty had a lasting impact on European history. We obtained ancient genomic DNA from the purported remains of Otto I (912-973) and Heinrich (Henry) II (973-1024), the first and last emperors of this dynasty, preserved in the cathedrals of Magdeburg and Bamberg, respectively. Historical records attest that they were related as a great-uncle and a grandnephew via the paternal line. Whole-genome sequencing confirms such a relationship between the two individuals, as we identify a third-degree genetic relationship based on shared DNA segments and infer matching Y haplogroups. This genetic relatedness effectively identifies the remains of the two emperors. The authentication yields a valuable resource for refining and calibrating bio-archaeological methods. Because historical records provide the precise lifespans and dates of death of these individuals, their remains can serve as a "ground-truth" for methods such as radiocarbon dating and age-at-death estimates. They can provide calibration data to improve our understanding of the radiocarbon reservoir effects of Medieval elites. As the Ottonian lineage was closely linked to the mating networks of elites across Europe, the genomes of the two emperors are valuable resources for identifying other potential elite burials.

Local ancestry inference classifies segments of DNA in admixed individuals by their originating population. However, as the date of admixture becomes older, these segments become shorter and determining their ancestry becomes increasingly difficult. This limits many existing segment-based methods to relatively recent historical admixture events and more highly diverged populations. The rapidly expanding availability of ancient DNA offers a promising opportunity to use these ancient samples as references for local ancestry inference. A recent approach integrates ancient samples into the ancestral recombination graph (ARG) for local ancestry inference. Here, we introduce recent advances in deep learning for graphs into this ARG framework to create ARGMix, a graph transformer that infers local ancestry using the coalescent trees of the inferred ARG. Our approach employs ancient samples as references in the marginal trees to predict local ancestry. We train ARGMix on data reflecting the well-understood ancient European demography and demonstrate improved accuracy and robustness even under demographic misspecification. We then apply ARGMix to an ARG of ancient and present-day European samples for ancestry-specific analyses, finding evidence of continuity between Otzi the Iceman and present-day individuals from nearby regions.

Sickle cell disease (SCD) is the most common inherited hemoglobinopathy worldwide. Improving the quality of life of people with SCD requires prenatal and neonatal screening. Our primary objective was to demonstrate that prenatal diagnosis of SCD is possible even in situations of poverty. Secondarily, we described the socioeconomic profile of couples seeking molecular diagnosis of SCD in Kinshasa, Democratic Republic of Congo. Methods This was a cross-sectional study conducted in Kinshasa between January 2020 and December 2025. During this study period, 107 couples underwent prenatal diagnosis. Prenatal diagnosis was performed using amniocentesis with FTA Elute technology. This diagnosis was confirmed at birth using cord blood DNA extracted via the conventional salting-out technique. Results The mean age of the pregnant women was 28 {+/-} 4 years. Eighty-one couples (75.7%) were Christian, nine couples (8.4%) were Muslim, and seventeen couples (15.8%) were animist. Eighty-two couples (76.6%) were known heterozygous AS couples, eleven (10.2%) were heterozygous couples, and fourteen (13.0%) were couples composed of one homozygous SS and one heterozygous AS partner. All pregnancies were singleton. Socioeconomic status was upper middle class (39.2%). The AS genotype was found in 79% of the fetuses. One intrauterine fetal death was observed after amniocentesis. In terms of handling, the FTA Elute technology reduces DNA extraction time to 30 minutes. It is easy to use. Results are available in less than 24 hours. Conclusion The FTA Elute technology is a reliable, less expensive, and easy-to-use prenatal screening technique for sickle cell disease. Sample transport and storage conditions are better suited to resource-limited settings.