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PeerJ

◐ PeerJ

Preprints posted in the last 90 days, ranked by how well they match PeerJ's content profile, based on 308 papers previously published here. The average preprint has a 0.34% match score for this journal, so anything above that is already an above-average fit.

1
biomes: An R package for reproducible occurrence-to-biome classification using 31 global biome schemes

Gross, H. C.; Zizka, A.; Fischer, J.-C.; Walentowitz, A.

2026-10-01 bioinformatics 10.64898/2026.09.25.754345 medRxiv
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Abstract 1. Biomes are continental-scale vegetation units widely used in ecological and evolutionary research, often together with large-scale species-distribution data. Many conceptually distinct biome schemes exist, differing in the underlying definition, delineation methodology and spatial resolution, yet most studies using biomes default to a few readily available schemes rather than choosing the one best suited to the research question. 2. We present biomes, an R package distributing spatially explicit raster layers of 31 published global biome schemes in a harmonised format at a 10 x 10 km resolution, together with metadata and a concise description. To facilitate their use, biomes provides a user-friendly classification workflow to classify occurrence records into specific biomes and a data-driven ranking algorithm to help researchers to choose the most suitable biome scheme for their data and research question in a transparent, reproducible way. 3. The biomes workflow can be applied to any dataset of georeferenced terrestrial occurrences. It (1) accepts either user-provided occurrence records or records downloaded by the package, (2) ranks the schemes according to their fit to the occurrence data, (3) assigns the records to specific biomes, and (4) summarises the resulting taxon-biome patterns. We demonstrate this workflow using 17,030 occurrence records of 185 species of Bombacoideae (Malvaceae). The analysis identified the vegetation-based biome scheme of Ramankutty and Foley (1999) as the best fit and recovered the forest and savanna biome signal known in the group from the literature, with tropical evergreen woodland being the biome with the largest share of records (46.1%) and highest number of species (162 of 185 species; 87.6%). 4. biomes provides user-friendly access to technically standardised and spatially explicit layers of 31 biome schemes, and thereby enables the transparent, data-driven choice of biome schemes tailored to a specific research data and questions, improving the reproducibility and the specificity of biome use across ecological and evolutionary research.

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Temperature modulates resting posture, microhabitat use, and day nesting in chimpanzees in a cool montane forest

Al Razi, H.; Muhayeyezu, F.; Mulindahabi, F.; Niyigaba, P.; Bantlin, D. A.; Kaplin, B. A.; Maloney, S. K.; Grueter, C. C.

2026-08-23 animal behavior and cognition 10.64898/2026.08.18.745634 medRxiv
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Behavioral thermoregulation allows animals to reduce the physiological costs associated with variation in the thermal environment, yet little is known about how chimpanzees respond behaviorally to the cool and humid conditions of tropical montane forests. We examined how microclimatic conditions influenced resting posture, sun/shade use, substrate use, vertical position within the canopy, and day nest use in eastern chimpanzees (Pan troglodytes schweinfurthii) in Nyungwe National Park, Rwanda. From March 2024 to February 2025, we collected 5,661 individual behavioral records during 486 contact hours and paired behavioral observations with measurements of ambient temperature, water vapor pressure, wind speed, and rainfall. Bayesian mixed models showed that temperature was the most consistent climatic correlate of resting behavior. Under cooler conditions, chimpanzees were more likely to adopt heat conserving postures, particularly curled and huddled postures, and to use day nests. As temperature increased, chimpanzees increased their use of shade, shifted from arboreal to terrestrial resting, and used lower canopy strata more frequently. Higher wind speed was also associated with reduced use of the upper canopy, whereas rainfall, water vapor pressure, and fruit availability generally showed weaker or behavior-specific associations. These findings indicate that chimpanzees in a cool montane forest flexibly adjust posture, solar exposure, substrate use, vertical position, and day nest use in relation to local thermal conditions. Resting behaviour may therefore provide an important context for behavioral thermoregulation, extending our understanding of chimpanzee thermal ecology beyond the warmer lowland and savanna habitats that have received most previous attention.

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Epidemic potential of Maravalia cryptostegiae, a classical biological control agent of rubber vine, in Northeastern Brazil

Del Ponte, E. M.; Costa, R. C.; Barreto, R. W. W.

2026-10-06 plant biology 10.64898/2026.10.05.756685 medRxiv
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Rubber vines (Cryptostegia madagascariensis and C. grandiflora) are highly invasive weeds in the semi-arid landscapes of many tropical regions. The rust fungus Maravalia cryptostegiae has provided a spetatular and sustainable control of invasive C. grandiflora populations in Australia, after its scientific and quarantine-authorized release in the context of a classical biological control program. The Caatinga biome of Northeastern Brazil is under a devastating invasion by C. madagascariensis. This species is also susceptible to M. cryptostegia but its epidemic potential towards C. madagascariensis in Brazil remains unknown. We developed a weather-driven epidemiological model integrating experimentally derived relationships for infection as a function of temperature and wetness duration and for temperature-dependent latent development. Three infection-response models were fitted to 20 experimental temperature x wetness combinations from the literature and compared using information criteria, grouped cross-validation and a parametric bootstrap. The selected model, in which thermal breadth increases with wetness duration, was best supported (R2 = 0.931; {Delta}AICc [≥] 3.3 relative to the alternatives), and prolonged wetness significantly broadened the thermal range favorable for infection ({gamma} = 0.30 oC h-1; bootstrap P = 0.002). The infection and latent-development models were coupled with 25 years (2001-2025) of hourly NASA POWER data for 65 grid cells representing rubber-vine-infested locations in Northeastern Brazil, with wetness defined as hours with relative humidity equal or greater than 90%. Infection potential was concentrated in March-June (73% of the annual total, peaking in April), coinciding with the regional rainy season, and was highest in the interior of northern and central Ceara. Predicted potential varied more than a hundredfold among grid cells and was lowest along parts of the Ceara coast and the lower Jaguaribe valley, which include some of the largest infestations; the magnitude of these contrasts depended on the humidity threshold used to define wetness. Applied with identical rules to 13 historical release sites in Queensland, Australia, the model reproduced the documented wet-season timing of rust activity, and predicted potential was on average higher at sites with reported high rust impact, although the difference was not statistically significant. These results indicate strong seasonal and geographic structuring of weather-driven epidemic potential and provide testable hypotheses for selecting release periods and locations for M. cryptostegiae in Brazil.

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Unexpected post-release behaviours of reintroduced kakapo

Digby, A.; Forrest, S.; Eason, D.; Klappstein, N.; Howie, D.; Montgomerie, C.; Ward, J.; Kakapo Recovery Team, ; Davis, T.; Vercoe, D.

2026-09-30 animal behavior and cognition 10.64898/2026.09.24.753978 medRxiv
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Translocations are commonly used to reduce the risk of extinction of threatened species, and often to reintroduce animals to their former habitats. If extirpation occurred a long time ago, individuals may be placed into novel environments outside of conditions they have previously experienced, which can affect translocation success. To measure success of translocations, particularly those to novel habitats, it is important to monitor post-release spatial behaviour. In 2023, ten critically endangered k[a]k[a]p[o] (Strigops habroptilus) were released to form a new population at the fenced mainland island of Sanctuary Mountain Maungatautari (hereafter Maungatautari) in the North Island of New Zealand, an area from which they were extirpated approximately a century earlier. The spatial behaviour and habitat selection of these k[a]k[a]p[o] was analysed using dynamic space use and step selection functions with temporally dynamic responses applied to GPS logger data recorded over a seven month period. These showed three unexpected results: k[a]k[a]p[o] were highly mobile and used larger areas compared to other sites; there was synchronicity of movement, with most individuals simultaneously moving toward the perimeter fence in spring; and when near the fence k[a]k[a]p[o] selected for areas of pasture and exotic vegetation more than anticipated. While direct comparisons are difficult due to varying data availability, this unexpected spatial behaviour and habitat selection suggests that k[a]k[a]p[o] behavioural responses were different at Maungatautari compared to other sites. This may indicate that k[a]k[a]p[o] released at Maungatautari had a longer exploratory stage than elsewhere; that there were behavioural effects influenced by conspecific density or the availability of novel and exotic vegetation; or that there were specific breeding habitat requirements not met at the site during the study period. These results highlight the importance of high-resolution spatial monitoring to evaluate the success of translocations, particularly those to novel environments.

5
Mapping human-macaque encounter potential by integrating visitor-use and macaque-use intensity in Kamikochi, Japan

Otani, Y.; Tsuchihashi, A.; Sugita, S.; Fukui, H.; Shikano, Y.; Matsumoto, T.

2026-07-31 zoology 10.64898/2026.07.30.741901 medRxiv
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Managing visitor-wildlife interactions in high-use protected areas requires identifying not only where visitors concentrate but also where visitor use overlaps with wildlife space use. We estimated relative human- macaque encounter potential in Kamikochi, Chubu Sangaku National Park, Japan, where Japanese macaques (Macaca fuscata) and visitors use the same frontcountry landscape. We integrated Mobile Spatial Statistics derived from mobile phone network data, trail-camera counts, and direct-follow location data from macaques along a frontcountry-backcountry gradient. Broad-scale 500-m grid estimates of daytime visitor presence for the 2023 and 2024 open seasons were allocated to 50-m trail sections and adjusted using counts from 10 trail cameras. Automated video counts based on YOLO11 and ByteTrack showed high agreement with manual counts of 100 validation videos (MAE = 0.10 persons/video, MAPE = 1.26%, exact agreement rate = 92.0%). Visitor-use and macaque-use data were converted into kernel density surfaces, and encounter potential was calculated as their normalized product. High encounter potential was concentrated in the central frontcountry: 87.1% of areas with index values [≥] 0.9 fell within the frontcountry and 12.9% within the backcountry. Areas with high visitor use or high macaque use alone did not necessarily show high encounter potential when the two distributions were spatially offset. These results show that spatial overlap provides management information not captured by visitor counts alone. Relative encounter potential can help prioritize patrols, visitor messaging, viewing management, and other interventions in protected areas where wildlife does not consistently avoid heavily used visitor spaces.

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The micro-plant remains preserved on lithics and in the associated sediment of the Hoabinhian Laang Spean cave site, Battambang province, Cambodia.

Kerfant, C. E.; Yang, R.; Clemente-Conte, I.; Heng, S.; Exposito, I.; Perez-Balarezo, A.; Puaud, S.; Zeitoun, V.; Viallet, C.; Justin, G.; Forestier, H.

2026-07-27 plant biology 10.64898/2026.07.26.740757 medRxiv
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AO_SCPLOWBSTRACTC_SCPLOWThis study seeks to advance understanding of how ancient Hoabinhian communities engaged with the diversity of their environments, focusing on plant resource management and the role of plants in technological and subsistence strategies at the Laang Spean site, Cambodia. The methodological approach relies on phytolith assemblages recovered from sediments associated with micro-plant residues adhering to the lithic tools, interpreted using anatomical and histological knowledge of plant tissues. Phytolith extraction from nine stratigraphic layers revealed distinct differences between Hoabinhian contexts (Stratigraphical Unit=SU): the layer 9 contained mainly palm trees phytoliths, while layers 10 and 11 showed higher phytolith diversity and diagnostic grass forms. Besides the Monocots strong assemblage results between the two main periods studied, a diversity of phytolith arboreal taxa indicate broader plant use and environmental complexity during Hoabinhian occupations (consistent with the other archaeobotanical studies held on Hoabinhian archaeological sites in the region). Upon the nine lithics artefacts studied, only one has delivered micro-plant remains identified as leaf-culm part of Monocots (plants that do not produce wood), and most probably of bamboo origin. This multidisciplinary research aims to refine interpretations of Hoabinhian plant exploitation (subsistence and environmental context), and contributes to current debates on "forest technologies" in Southeast Asia.

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Two Novel Rod-Like Circular RNAs from the Oroarctic Tundra Soil Display Candidate Ribozyme-Like Features: An In Silico Characterization

Williams, N.; Wolfram, G.; Zhang, A.; Tessler, M. E.; Jung, G.

2026-07-27 microbiology 10.64898/2026.07.27.740603 medRxiv
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The recent discovery of obelisks, novel deltaviruses, and other viroid-like circular RNAs has greatly expanded the known diversity of autonomous RNA elements. However, cold terrestrial ecosystems remain comparatively undersampled for these molecules. Using a structure-based modification of the Tormentor pipeline, we assembled two putative non-coding rod-like circular RNAs from winter metatranscriptomes of oroarctic tundra soil collected near Kilpisjarvi, Finland. Sequence-based searches identified no meaningful homologs for either RNA. Structure-based analyses identified affinities to deltavirus-like ribozymes in Rod 1 and to hammerhead ribozymes in Rod 2, with structural compatibility confirmed by integration into an established covariation model. Rod 1 was additionally detected in independent alpine metatranscriptomic datasets, whereas Rod 2 was not identified beyond the original sample. Collectively, these results identify Rod 1 as a strong candidate viroid-like RNA bearing a putative ribozyme-like structure motif that warrants experimental validation, while Rod 1 remains a preliminary candidate requiring further confirmation.

8
Oncogenes have the most distinct codon biases in the genome and codon signatures that oppose tumor suppressor genes

Mathur, C.; Davis, E. T.; Ehrbar, D.; Omeoga, H. C.; Endres, L.; Byrne, S. R.; Begley, U.; Dedon, P. C.; Begley, T. J.

2026-08-24 cancer biology 10.64898/2026.08.21.746283 medRxiv
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Oncogenes and tumor-suppressor genes play opposing roles in cancer biology to promote and restrict growth, respectively. Codon usage patterns interface with tRNA modifications to control translation, leading to gene-specific codon signatures with regulatory potential. As such, codon-biased translational regulation has been identified as a driver of proliferation and drug resistance in multiple cancers. We used advanced codon analytics methods to characterize and compare codon usage bias in oncogenes and tumor suppressor genes (TSGs) from humans and mice at group and gene-specific levels. We demonstrate that human oncogenes exhibit a distinct and opposing codon usage pattern to TSGs. This phenomenon is also present in mice but with less distinct oncogene bias relative to humans. Further comparison to 447 gene ontology groups demonstrated that human oncogenes have the most distinct codon usage patterns in the genome, while also highlighting that codon bias can separate functionally related genes and pathways from other biological processes. Using gene-specific codon analytics, we determined that human oncogenes have two types of extreme codon bias: a large group (N = 43) over-using G/C ending (GC3) codons and a smaller group (N = 12) over-using A/U (AU3) ending codons. While GC3 bias has been linked to increased translation in general, the AU3 finding suggests that genetic, environmental, or stress-related signals could drive the translation of this small group of oncogenes. The less extreme bias observed in mouse oncogenes and tumor suppressors likely underscores species-specific differences in oncogenic translation programs. Together, our findings highlight codon usage bias as a potential determinant of oncogene expression, provide a framework for ontology-based codon analysis, and uncover on species-specific differences in oncogene translation and codon usage biases.

9
Its just a phase: moonlight and rainfall influence the activity of a threatened cave-roosting bat in the Pilbara

Westerhuis, E. L.; Kaestli, M.; Grabham, C.; North, H.; Madani, G.; Armstrong, K.; O'Brien, J.

2026-08-21 ecology 10.64898/2026.08.20.746117 medRxiv
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Wildlife monitoring in arid environments is complicated by substantial temporal and spatial variation in animal activity driven by unpredictable environmental conditions. For highly mobile species, movements across the landscape may further influence activity recorded at fixed monitoring locations, raising questions about whether short-term surveys adequately represent patterns of site use. We examined temporal variation in acoustic activity of the threatened Pilbara Leaf-nosed Bat (Rhinonicteris aurantia Pilbara form), a highly mobile, cave-roosting insectivorous bat inhabiting the arid Pilbara region of north-western Australia. Acoustic activity was monitored continuously at two permanent diurnal roosts for up to two years, comprising 1601 detector-nights across three detector locations. We tested relationships between nightly activity and environmental conditions, detector location and anthropogenic disturbance. Activity varied substantially through time and among detector locations. Moon illumination and cumulative rainfall were strongly associated with activity, but their interaction differed between roosts: activity was highest under low moon illumination and low cumulative rainfall at Chateau Cave, whereas activity at Daltons was highest under low moon illumination and higher cumulative rainfall. Activity also differed markedly between detector positions within Chateau Cave, and humidity, temperature and artificial light at night had additional location-specific effects. Other measures of anthropogenic disturbance, including cave entry, blasting and mining activity, had comparatively weak support. The contrasting environmental relationships among locations demonstrate that acoustic activity at permanent roosts is strongly context dependent. For a species capable of extensive movements among roosts, temporal variation in activity may reflect behavioural responses and redistribution of individuals across the landscape rather than rapid demographic change. We suggest that facultative nomadism may provide a useful hypothesis for understanding temporal variation in roost use by Pilbara Leaf-nosed Bat. More broadly, our results demonstrate that short-duration acoustic surveys of highly mobile species in arid environments may provide an incomplete representation of longer-term site use and should incorporate temporal replication and environmental context when used for conservation and impact assessment.

10
Unique pattern of injuries in Olenoides serratus from the Burgess Shale elucidate moulting process in trilobites

Losso, S. R.; Bicknell, R. D. C.

2026-09-24 paleontology 10.64898/2026.09.18.752702 medRxiv
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Ecdysozoans is one of the most abundant and diverse groups of metazoans and grow through moulting the rigid exoskeleton that provided protection. But the moulting process is often dangerous, resulting in malformations or death. Injuries have been well documented in the calcitic exoskeleton of trilobites, some of which have been attributed to moulting complications when long spines are deformed. Injuries in trilobites are often found in the trunk rather than the cephalon, and abnormal genal spines are rarely documented. Here we examine injuries in eleven specimens of Olenoides serratus from the Burgess Shale (Cambrian, Wuluian) and demonstrate an increased frequency of genal spine malformations compared to other trilobites. The unusual pattern of malformations may be attributed to moulting injuries of the long and delicate genal spines in O. serratus. To moult, trilobites curved ventrally to press the anterior margin of their cephalon into the substrate and open the facial sutures. This process exerted force on the librigenae. To exit the exuvia, the genal spines were forced to bend as the old librigenae dipped ventrally along the anterior edge, resulting in the injured genal spines in O. serratus. A similar process of moulting resulting in injuries may be seen in other early Euarthropods.

11
Hibernation site dimensions influence bat abundance and diversity in the boreal zone

Matlova, M.; Blomberg, A. S.; Tidenberg, E.-M.; Basok, M.; Lilley, T.; Fjelldal, M. A.

2026-08-21 ecology 10.64898/2026.08.18.745443 medRxiv
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Hibernation is a critical phase in the annual cycle of boreal bats, especially near the northern limit of their range where winter conditions are severe and suitable hibernacula are limited. In Finland, anthropogenic structures, such as abandoned bunkers, commonly serve as hibernacula for bats. In this research, we investigate how the size characteristics of bunkers affect species composition and abundance of hibernating bats. The length of the bunker was the best predictor of the presence and abundance of bats. The longest sites ([~]25-26 m) had the highest probability to host all studied species, or group of species of bats, specifically Eptesicus nilssonii, Plecotus auritus, and Myotis bats. Eptesicus nilssonii appeared to be a generalist species, utilizing a variety of bunkers regardless of their length or temperature regime. Still, its number per bunker was relatively low. The highest numbers of Myotis bats were observed in the longest bunkers with stable temperature. The number of P. auritus was positively related to the bunker length; however, it was rare in the studied hibernacula. Different species showed different patterns in hibernacula space usage. Eptesicus nilssonii hibernated in any part of the bunker, while Myotis bats used the most remote from the entrances areas in small sites, and occupied the whole area of the longest bunkers.

12
A large-scale evaluation of tree shape indices reveals potential pitfalls

Haeuser, L.; Stamatakis, A.

2026-09-04 evolutionary biology 10.64898/2026.09.03.748783 medRxiv
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While there exists a plethora of prior research on phylogenetic tree shape indices, a large-scale analysis of the behavior of these indices on empirical trees has not yet been conducted.Here, we address this by computing 54 indices on more than 45,000,000 empirical trees retrieved from the EvoNAPS and RAxML Grove databases. To calculate the indices, we use our novel, comprehensive open-source Python library called treeshapy. The results of our large-scale evaluation indicate that there exist several potential pitfalls when conducting tree shape studies. For $14$ indices we find clear indications, that they are highly sensitive to the position of the tree's root. Only $5$ indices appear stable in that sense, while we observe a medium degree of rooting instability for the remaining $35$ indices under study. Therefore, uncertainties pertaining to the root placement directly affect tree shape values. Furthermore, the values of all except $5$ indices are inherently correlated with tree size, even so, when applying adequate normalization techniques. As a consequence, tree shape values for trees of different sizes should generally not be compared. We further observe that several groups of indices are strongly correlated with one another. Hence, to conduct a representative tree shape study, an appropriate subset of uncorrelated indices should be selected to capture as many aspects of the tree shape as possible while avoiding essentially redundant results at the same time. Our study serves as a guide for conducting tree shape studies in a more cautious and comprehensive manner on empirical data. Apart from our open-source treehshapy Python package, we devise appropriate guidelines for selecting suitable indices and cautiously interpreting respective results.

13
Genomic characterization reveals high clonal redundancy in two Acropora cervicornis nurseries in the Dominican Republic

Anseeuw Carrasco, S.; Walsh, K. H.; Garcia-Camps, R.; Zubillaga, A. L.; Croquer, A.; Bhattacharya, D.

2026-09-12 ecology 10.64898/2026.09.11.750210 medRxiv
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Acropora cervicornis is often propagated through fragmentation (i.e., clonal propagation), a common practice implemented by restoration projects. Known as asexual propagation, this strategy may rapidly increase coral cover but reduces genetic variation. We used 2b-RAD sequencing to characterize multilocus genotypic variation among 45 A. cervicornis colonies maintained in two in-situ nurseries (Cap Cana, Acuario) in Punta Cana, Dominican Republic. After reference-based SNP discovery and filtering, 2,515 high-quality SNPs were retained in the dataset. Principal coordinate analysis (PCoA), hierarchical clustering, identity-by-state (IBS) distances, and relatedness estimates identified only three multilocus genets among the 45 colonies (AC1, AC2, and AC3). Of these, AC2 was the most abundant (n = 23; 51.1%), followed by AC3 (n = 14; 31.1%) and lastly AC1 (n = 8; 17.8%). Within-genet IBS distances (0.153-0.227) did not overlap with between-genet distances (0.406-0.497). AC1 and AC2 were detected in both nurseries, whereas AC3 was limited to Acuario. These results reveal substantial clonal redundancy among sampled nursery colonies that determines local reef conservation efforts. These data highlight the value of incorporating genotype identification in nursery-based coral restoration projects.

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Detecting Random Mutations in 16S rRNA Sequences

Haworth, R. M.; Commichaux, S.; Pop, M.

2026-09-29 bioinformatics 10.64898/2026.09.24.753821 medRxiv
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Motivation: High-throughput sequencing technologies have driven rapid growth of biological sequence databases. Public repositories must therefore rely on automated computational heuristics to screen submitted sequences for errors and low quality. For example, SILVA SSU Ref, which exploits the conserved nature of 16S and 18S rRNA sequences, applies strict algorithmic quality controls yet still accepts sequences with up to 30% of their nucleotides deviating from any previously accepted sequence. This permissiveness creates opportunities for the admission of modified sequences, such as biologically plausible sequences generated by DNA foundation models. The vulnerability of public sequence databases to becoming polluted or poisoned with modified sequences necessitates the development of methods to detect such sequences. Results: We present the first investigation, to our knowledge, of the detectability of modified sequences. We consider simple computationally-modified 16S rRNA sequences that pass the quality control inclusion criteria of the SILVA database, which we generate via random substitutions. We present classifiers that can distinguish such modified sequences from natural 16S rRNA using conserved motifs. Our best classifier achieves over 90% sensitivity and specificity on our testing set when using a 5% artificial mutation rate. One feature used in our classifiers, gapped k-mers constructed from universally conserved nucleotides, was conserved across all three domains of life despite relying on exact matches to patterns found in E. coli, advancing our understanding of conserved grammatical structure in small subunit rRNA sequences. Availability and Implementation: Our source code is available at https://github.com/rainhaworth/16S-Mutation-Classifiers.

15
Effect of CT-based material grouping on finite element strength and stiffness predictions in vertebrae with metastatic lesions

Strack, D.; Rehtanz, N.; Soltani, Z.; Keko, M.; Subburaj, K.; Alkalay, R. N.

2026-08-24 oncology 10.64898/2026.08.20.26360953 medRxiv
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Introduction: Metastatic spinal lesions substantially alter vertebral mechanical properties and increase fracture risk. Computed tomography (CT) based finite element (FE) models can estimate vertebral strength, but their accuracy depends on how CT derived material properties are represented. This study evaluated the effect of two material grouping strategies on simulated strength and stiffness in metastatic vertebrae. Methods: We compared Adaptive Clustering (AC) with Uniform fixed width grouping in 44 vertebrae from 11 donors (8 osteolytic, 12 osteoblastic, 12 mixed, 12 no observed lesion (NOL)). FE models were generated based on CT scans with 2 to 500 material groups and compared for material mapping error and simulated strength and stiffness. Overall and lesion stratified agreement with experimental measurements was assessed in an exploratory analysis. Results: AC showed significantly lower Young's modulus root mean square error than Uniform (p < 0.05). Simulated strength and stiffness stabilised by 50 material groups. At 50 groups, simulated strength showed moderate correlation with experimental strength overall (R2 = 0.57), strongest in NOL vertebrae (R2 = 0.82) and lower in lesion-bearing vertebrae (R2 = 0.4-0.59). Stiffness showed weaker correlation overall (R2 = 0.27), highest in NOL vertebrae (R2 = 0.48) and negligible in mixed lesions (R2 = 0.007). Bland Altman analyses indicated systematic underestimation of experimental fracture load. Discussion: AC improved material-mapping fidelity, whereas increasing material groups beyond 50 had little influence on simulated strength or stiffness. Numerical stabilisation therefore did not imply experimental accuracy. Lesion stratified findings were exploratory and should be interpreted cautiously because of limited subgroup sizes.

16
The Barcode Inference Pipeline (BIP): From Sequencer Output to DNA Barcodes

Prosser, S. W.; Thompson, K. A.; Bard, N. W.; Floyd, R. A.; Ozsahin, E.; Hebert, P. D. N.

2026-07-24 bioinformatics 10.64898/2026.07.21.739876 medRxiv
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DNA barcoding involves the recovery of a DNA sequence for a target gene region from its source specimen. This process gains complexity when multiple sequences are recovered from a specimen, as is often the case when data are generated by high-throughput sequencers. This diversity can reflect both methodological artifacts (e.g., chimeras, PCR errors, sequencing errors, tag jumps) and real template diversity in the DNA extract (e.g., contamination, endosymbionts, NUMTs, parasites). To support analysis of the sequence data from three million specimens annually, the Centre for Biodiversity Genomics (CBG) has developed BIP, the Barcode Inference Pipeline. Compatible with all sequencing platforms, BIP processes .fastq files and returns both target DNA barcodes and non-target sequences. To generate results, BIP implements quality and size filtration, demultiplexing, primer trimming, chimera scanning, sequence error correction, OTU delineation, and sequence identification. When analysis targets the cytochrome c oxidase 1 (COI) barcode region, BIP also assigns each OTU to a known BIN or identifies its nearest neighbour BIN. As final output, BIP returns summary files ready for upload to BOLD or for other downstream analyses. They include a taxonomic assignment for each OTU, generated by comparison with a DNA barcode reference library. We describe BIPs flexibility and structure, then demonstrate its functionality by analyzing COI sequence data from 100K specimens. Because of its capacity to disentangle target and non-target sequences, BIP outperforms an alternative software package, ONTbarcoder, in several important ways. To ease access, installation, and functionality, BIP is provided as a Docker container (github.com/cbg-innov/BIP).

17
Snails show their true colours: rate of evolutionary divergence in the shell colour polymorphism of Cepaea nemoralis

Kwarten, G. L.; Schilthuizen, M.

2026-09-17 evolutionary biology 10.64898/2026.09.14.749438 medRxiv
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The shell colour polymorphism in the land snail Cepaea nemoralis is maintained by environmentally variable light intensity and predation. Previous work showed that divergence in colour polymorphism between habitat pairs of open and closed areas increased with age of the habitat. However, that study was limited to a time span of 80 years (27 snail generations). Here, we investigate shell colour divergence over habitat pair ages of 95 to 325 years. We did find an increase in evolutionary divergence of colour polymorphism with increasing age, however equilibrium could not be determined. This is possibly due to the evolutionary effect of camouflage working in opposite direction to light intensity in certain locations, consequently clouding the results. Therefore, camouflage might also be an important factor to take into account in the search for the evolutionary equilibrium of colour polymorphism in Cepaea nemoralis.

18
Culture Positivity Reflects Quantitative Bacterial Bioburden in Open Fractures

Ross, B. D.; Gitajn, I. L.; McClure, E. A.; Natoli, R. M.; Castillo, R. C.; Carlini, A. R.; Wenke, J. C.; O'Toole, R. V.; Schrank, G. M.; Obremsky, W. T.; Warner, S. J.; Bosse, M. J.; Major Extremity Trauma Research Consortium,

2026-09-23 microbiology 10.64898/2026.09.22.753238 medRxiv
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Infection following high-energy open fractures remains a major challenge. Open fractures are exposed to environmental and skin pathogens, which, along with traumatized tissue and implanted hardware, create a favorable environment for infection. 24-83% of open fractures yield positive culture results. Despite culture-positive wounds being at higher risk for infection, culture data are rarely used in clinical decision-making. Culture-positivity in open fractures is believed to indicate higher wound bioburden, but this hypothesis remains unconfirmed. This study aimed to correlate culture positivity and quantitative wound bioburden using next-generation sequencing (NGS) and to characterize patterns of bioburden and bacterial diversity amongst patients with open fracture and Fracture Related Infection. We hypothesized that higher wound bioburden would be associated with culture positivity. This secondary analysis of the METRC Bioburden Study included 78 patients with severe open tibia fractures who underwent standardized tissue sampling at definitive wound closure and at later fracture site revision surgery. DNA extracted from intraoperative tissue was analyzed via 16S rRNA gene amplicon sequencing. Quantitative bioburden metrics included bacterial read percentage and bacteria-to-human read ratio (BHR). Associations between sequencing-based bioburden, culture results, and clinical infection (CDC-defined) were evaluated using Mann-Whitney U tests, McNemars chi-squared tests, and unsupervised clustering analyses. Culture-positive samples exhibited significantly higher bacterial read percentages and higher log(BHR) values than culture-negative samples. Optimal thresholds yielded high sensitivity and specificity for both bacterial reads and BHR for predicting culture positivity. Neither baseline culture nor NGS positivity predicted later infection. However, follow-up samples from patients with established infection showed significantly higher bioburden and distinct microbiome structures. Clustering analyses identified two infection-associated microbial profiles: one with high bioburden and high diversity (polymicrobial infection) and one with low bioburden and low diversity (single-dominant pathogen). Culture positivity in open fractures correlates strongly with increased bacterial bioburden, indicating that positive cultures may primarily reflect microbial load rather than specific pathogens. Quantitative NGS-based measures, including bacterial read proportion and BHR, may offer a biologically grounded approach to assess wound contamination and may inform infection risk. Distinct bioburden-diversity patterns suggest heterogeneous infection phenotypes that may require tailored surgical and antimicrobial strategies.

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Heart rate of the blue mussel Mytilus edulis in a simulated intertidal environment

Pham, D. N.; Sokolova, I. M.

2026-10-02 physiology 10.64898/2026.09.28.754745 medRxiv
Top 0.2%
8.1%
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Despite being a topic of early experimental studies, the effects of immersion-emersion cycles and temperature on the heart rate of intertidal Mytilus mussels have not been fully characterized. Using a recently released intertidal chamber paired with our own software package, we conducted a multiday experiment and continuously monitored the heart rate of the blue mussel Mytilus edulis. Under normal conditions, we detected a subtle spike in heart rate upon emersion before the eventual decline, as well as an overshoot upon reimmersion. Additionally, heart rate was sensitive to temperature changes during immersion but less responsive during emersion. These patterns were markedly altered following an unintended prolonged emersion event, which led to the loss of the emersion spike, an extended reimmersion overshoot, and heightened thermal sensitivity on top of an overall elevation in heart rate. However, the heart rate gradually returned to the pre-event baseline over the following days, demonstrating the significant resilience of the mussels. Our study highlights the potential of high-resolution physiological data in assessing the effects of environmental stressors on coastal ecosystems.

20
Estimating age and annual tooth growth rates in narwhals (Monodon monoceros) using computed tomography

Podolskiy, E. A.; Shimbo, G.; Park, S.-M.

2026-09-01 zoology 10.64898/2026.08.27.747649 medRxiv
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8.1%
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The spiraling tooth of the narwhal (Monodon monoceros) has long intrigued scientists, but the growth rates of its "tusk" are poorly constrained due to the difficulty to age narwhal. To learn more about the population dynamics and life history of this exploited species, previous studies have used sectioned teeth to age narwhals and calibrate other ageing methods based on aspartic acid racemization, radiocarbon or trace element analysis. However, few such studies have been conducted due to the method's difficulty and the need to sacrifice the tooth. In this study, computed tomography (CT) was used on five teeth as a non-destructive means of estimating the age of narwhals, revealing different growth rates between erupted and embedded teeth during adolescence. Moreover, in combination with our reanalysis of all relevant literature, CT data clarify the annual growth rates of narwhal tusks, which peak before the age of 10 (~100 mm yr-1). This approach will be useful for investigating private and museum collections, and might also better constrain the use of trace element proxies in narwhal teeth and support sustainable harvest management.