Biology subjects

Rascovan, N.

Publications and source records attributed to Rascovan, N..

6 recordsLinked to original sources

bioRxiv2026

Region-specific patterns of sexual shape variation in the human bony labyrinth: 3D geometric morphometric analysis of a sample with known genomic sex

The human bony labyrinth has attracted increasing interest because of its taxonomic, evolutionary, and functional significance. Although sexual dimorphism has been reported in several aspects of the temporal bone, the extent to which sex, age, size, and allometry contribute to labyrinth shape variation remains poorly understood. Here, we investigated patterns of sexual shape variation in the human bony labyrinth using three-dimensional geometric morphometrics in a sample of 98 archaeological individuals from South America with known genomic sex. Centroid size and allometric effects were assessed in a subset of 90 individuals with comparable metric scaling. In addition to analysing the complete labyrinth, the cochlea and semicircular canals were examined separately to evaluate region-specific patterns of sexual shape variation. Principal Component Analysis showed extensive overlap between females and males, and overall labyrinth shape did not differ significantly between sexes. Males exhibited significantly larger labyrinths than females, and centroid size explained a small but significant proportion of overall shape variation. Regional analyses showed no evidence of significant sexual shape differences in the cochlea or in any individual semicircular canal when analysed separately. In contrast, the combined semicircular canal system exhibited subtle but significant sexual shape variation independent of centroid size, whereas morphological disparity did not differ between sexes. The geometric comparison of the female and male consensus configurations further showed that sexual shape variation was regionally heterogeneous. Whereas the cochlea exhibited a pattern of localized changes with low directional coherence, the semicircular canals displayed more coordinated regional shape changes. The male consensus also exhibited slightly higher canal circularity across all three semicircular canals, particularly the posterior canal, while differences in canal-plane orientation remained minimal. These findings demonstrate that sexual shape variation in the human bony labyrinth is subtle and anatomically partitioned among its components. Although significant sex differences in centroid size were detected across most anatomical regions, overall labyrinth shape and cochlear morphology were primarily influenced by allometry, whereas significant sex-related shape differences were detected only when the semicircular canals were considered as an integrated anatomical system. These findings demonstrate that sexual dimorphism in the human bony labyrinth is subtle but regionally heterogeneous, with the cochlea and semicircular canals exhibiting distinct patterns of shape variation, suggesting that these structures are influenced by different developmental, functional, and evolutionary processes.

evolutionary biology↗

bioRxiv2025

Ancestry, admixture, and pathogens in contemporaneous Neolithic farmers and foragers on the Island of Gotland

Two archaeological cultural complexes coexisted on Gotland for over 500 years, between [~]3300 and 2800 calBCE, i.e. the Neolithic Funnelbeaker culture (FBC), and the Pitted ware culture (PWC). The ancestry of the FBC farmers and PWC marine foragers largely aligns with European Neolithic Farmers and European Mesolithic foragers, respectively, but the direct interactions between the groups on Gotland is not understood. We present a Middle Neolithic (MN) high-coverage genome and a Late Neolithic (LN) low-coverage genome from the Ansarve FBC dolmen. We investigate ancestry, admixture, and pathogens among these MN farmers (n =6), foragers (n=19), and a LN individual. We find that recent gene-flow between farmers and foragers could have taken place, although most gene-flow happened prior to their coexistence on the island. We also find evidence of different Yersinia pestis strains in the three cultural groups, showing that the pestis was widespread among groups with different subsistence strategies.

genomics↗

bioRxiv2025

{micro}CT Scanning Effects on DNA and a Multi-Step Workflow for Archaeological Petrous Bones

The petrous portion of the temporal bone is a key element in human evolutionary studies due to its exceptional preservation of biomolecules and morphological information. However, intensive and often redundant sampling has raised concerns about sustainability and long-term conservation. Here we present the first systematic evaluation of whether micro-Computed Tomography ({micro}CT)--a widely used tool for digital preservation--affects ancient DNA (aDNA) integrity in human petrous bones. We analyzed 93 archaeological samples from Argentina, of which 50 had been scanned using {micro}CT and 43 had not. We compared six molecular parameters, including endogenous content, read length, cytosine deamination patterns and contamination estimates. No statistically significant differences were observed between scanned and unscanned samples across any parameter (Mann-Whitney/Wilcoxon tests, p <0.05). Although mitochondrial contamination was marginally higher in scanned samples (p = 0.051), this was not driven by contamination estimates above the widely accepted 5% threshold for genomic analysis, Moreover, this pattern was not observed when considering nuclear contamination. These results indicate that, under appropriate scanning conditions, {micro}CT imaging does not compromise DNA preservation. Building on this evidence, we propose a sustainable, multi-step workflow that integrates biological profiling, osteobiography, imaging, and compositional pre-screening prior to molecular sampling. This interdisciplinary approach maximizes the scientific information obtained from skeletal collections while minimizing destructive practices, thereby promoting ethical and sustainable research on irreplaceable anthropological remains, and fosters collaboration across research fields.

paleontology↗

bioRxiv2025

Paratyphoid Fever and Relapsing Fever in 1812 Napoleon's Devastated Army

During Napoleons retreat from Russia in 18121, countless soldiers of the French army succumbed to infectious diseases, but the responsible pathogen or pathogens remain debated2-5. We recovered and sequenced ancient DNA from the teeth of 13 soldiers who, based on historical records, likely died from infectious diseases, aiming to identify the pathogens responsible for their deaths6. Our results confirmed the presence of Salmonella enterica subsp enterica belonging to the lineage Para C, the causative agent of paratyphoid fever7 ; and Borrelia recurrentis, responsible for relapsing fever transmitted by body lice8. We were not able to detect Rickettsia prowazekii (the agent of typhus) and Bartonella quintana (the cause of trench fever), which had previously been associated with this deadly event, based on PCR results and historical symptom descriptions3. The presence of these previously unsuspected pathogens in these soldiers reveals that they could have contributed to the devastation of Napoleons Grande Armee during its disastrous retreat in 1812. HighlightsO_LIGenetic evidence of S. Paratyphi C and B. recurrentis in Napoleonic soldiers C_LIO_LIPhylogeny-driven authentication workflow for ultra-low-coverage pathogen aDNA C_LIO_LIHistorical descriptions of Napoleons army illness match paratyphoid fever symptoms C_LIO_LIMultiple infections likely contributed to the collapse of Napoleons 1812 campaign C_LI

microbiology↗

bioRxiv2024

Global evolutionary patterns of Yersinia pestis and its spread into Africa

The zoonotic pathogen Yersinia pestis, the etiologic agent of plague, has caused three major pandemics and diversified in different lineages currently established in endemic areas worldwide1-3. However, some regions like continental Africa have been poorly covered within the global diversity and epidemiological history of this pathogen2,4-6. Here, we report the whole-genome sequences of 1,124 Y. pestis isolates collected from endemic areas worldwide over 116 years, nearly doubling the available genomic data for the species. By integrating population genomics and historical research, we retrace the introduction of multiple Y. pestis lineages into continental Africa, revealing the diversity of the 1.ANT lineage, its historical emergence and its spread to and within Africa since the late 17th century. We identify key mechanisms of genome evolution, including signatures of adaptive evolution present in virulence and biofilm-related genes such as RovA, a master virulence regulator, which likely play a role in the pathogens adaptation and endemic persistence. Additionally, our findings reveal an increased trajectory of genome degradation and expansion of IS elements in different lineages. This trend appears especially pronounced in 1.ANT genomes, promoting the remarkable genomic variation within this lineage. Taken together, our findings shed light on the introduction and evolutionary history of plague in Africa and provide a comprehensive framework for understanding the global diversity and genome evolution of Y. pestis, revealing potential factors contributing to its long-term adaptation in endemic areas.

microbiology↗

bioRxiv2023

decOM: Similarity-based microbial source tracking of ancient oral samples using k-mer-based methods

BackgroundThe analysis of ancient oral metagenomes from archaeological human and animal samples is largely confounded by contaminant DNA sequences from modern and environmental sources. Existing methods for Microbial Source Tracking (MST) estimate the proportions of environmental sources, but do not perform well on ancient metagenomes. We developed a novel method called decOM for Microbial Source Tracking and classification of ancient and modern metagenomic samples using k-mer matrices. ResultsWe analysed a collection of 360 ancient oral, modern oral, sediment/soil and skin metagenomes, using stratified five-fold cross-validation. decOM estimates the contributions of these source environments in ancient oral metagenomic samples with high accuracy, outperforming two state-of-the-art methods for source tracking, FEAST and mSourceTracker. ConclusionsdecOM is a high-accuracy microbial source tracking method, suitable for ancient oral metagenomic data sets. The decOM method is generic and could also be adapted for MST of other ancient and modern types of metagenomes. We anticipate that decOM will be a valuable tool for MST of ancient metagenomic studies.

bioinformatics↗