Unveiling the complexity of post-Roman polity formation using ancient DNA

Veeramah, K. R.; Tian, Y.; Koncz, I.; Farago, N.; Knipper, C.; Friedrich, R.; Vyas, D. N.; Samu, L.; Spekker, O.; Szeniczey, T.; Hajdu, T.; Mende, B.; Tomka, P.; Pap, I. K.; Czigany, D.; Radzeviciute, R.; Traverso, L.; Gnecchi-Ruscone, G. A.; Francalacci, P.; Schöne, B.; Toth, G. A.; Szecsenyi-Nagy, A.; le Roux, P.; Alt, K. W.; Hofmanova, Z.; Pohl, W.; Krause, J.; Vida, T.; Geary, P. J.

doi:10.1101/2025.08.18.670760

Home/Archive/bioRxiv

bioRxiv · 10.1101/2025.08.18.670760

Unveiling the complexity of post-Roman polity formation using ancient DNA

View original source ↗Export metadata ↓

Abstract

The transformation of the Roman world (4th-9th centuries CE) culminating in the dissolution of the Western Roman Empire in the 5th century marked a fundamental transition in European history. "Barbarian" groups and Roman provincial societies merged into enduring political frameworks in some places but not in others. Key questions persist regarding the regionally specific nature of this transformation. Here, we present one of the most densely sampled early medieval datasets to date, enabling the reconstruction of a post-Roman polity at an unprecedented micro-regional resolution. Our integrated genetic and archaeological analysis of two Roman-period (n=68) and five post-Roman (n=246) sites from the Little Hungarian Plain, a former Roman frontier region, reveals a significant increase in Northern European genetic ancestry, likely reflecting a large-scale population movement into the region. Moreover, while all post-Roman sites, dated to the time of the Langobard Kingdom, share similar genetic profiles, burial practices, and material culture, they display distinct patterns of social organization, especially regarding the role that biological relatedness played in each community. Our results suggest that distinct social hierarchies might have existed between sites, and their intensive connectivity probably formed the basis for regional-level organisation within the post-Roman polity. Our study provides a framework for investigating how new polities take shape after the collapse of major political systems. Applied more broadly, this approach can deepen our understanding of societal transformation across early medieval Europe and beyond, offering a richer and more nuanced view of the human past than ever before.

Explore related subjects

evolutionary biology Preprint

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

Veeramah, K. R., Tian, Y., Koncz, I., Farago, N., Knipper, C., Friedrich, R., Vyas, D. N., Samu, L., Spekker, O., Szeniczey, T., Hajdu, T., Mende, B., Tomka, P., Pap, I. K., Czigany, D., Radzeviciute, R., Traverso, L., Gnecchi-Ruscone, G. A., Francalacci, P., Schöne, B., Toth, G. A., Szecsenyi-Nagy, A., le Roux, P., Alt, K. W., Hofmanova, Z., Pohl, W., Krause, J., Vida, T., Geary, P. J.. 2025-08-19. Unveiling the complexity of post-Roman polity formation using ancient DNA. https://doi.org/10.1101/2025.08.18.670760

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Ocean current models predict spatial structure for coastal biodiversity

Genomic diversity provides the raw material through which all evolutionary processes occur. Accurately describing how environmental features affect patterns of diversity shows promise in predicting the resilience of populations and entire communities to dynamic environments and novel stressors. Identifying the contribution of purely neutral responses to environmental effects can be difficult, especially across large spatial ranges with many covarying environmental features. Using an individual-based model of larvae carried by ocean currents, we predict patterns of neutral genomic diversity in a passively dispersed coastal species, suggesting large geographic regions of relative homogeneity with ancestry determined by the nearest "upstream" population with limited larval input. The genomic identity that dominates each region sharply transitions at the next such interruption, generating hierarchical structure and violating assumptions of isolation-by-distance. We call these upstream populations "lineage source regions" (LSRs), and we find strong concordance between LSR model predictions and an empirical population genomic survey of a keystone salt marsh mussel (Geukensia demissa). We quantitatively validate model performance and goodness-of-fit, updating baseline predictions of genomic diversity patterns from the classic isolation-by-distance model to this LSR framework. This spatially explicit coastal ancestry model has potential for generalization across passive dispersing species.

evolutionary biology↗

bioRxiv2026

TaxaAudit: A statistical model of consensus in phylogenetics identifies non-monophyletic taxa

Interpreting variation in genes and traits across species requires understanding their evolutionary relationships. Taxonomic hierarchies provide a practical approximation of the tree of life, with the NCBI taxonomy linking this framework directly to public sequence data. Some named groups, however, are not evolutionary clades, and recognizing these exceptions requires knowledge scattered across the phylogenetics literature. Here we introduce TaxaAudit, a statistical model that identifies taxonomic groups whose monophyly is repeatedly contradicted by published phylogenies. The model accounts for background taxonomic conflict and the ability of each study's species sampling to expose non-monophyly. Applied to 5,865 molecular phylogenies from TimeTree, TaxaAudit flagged 516 NCBI taxa at family rank and below for significant recurrent contradiction of monophyly. Excluding these taxa's monophyly requirements improved the taxonomy's agreement with independent phylogenomic reference trees and phylogenies withheld from discovery. Flagged taxa were also 3.61 times as likely as matched controls to have their monophyly challenged in publications outside the discovery set. In tree-inference experiments, excluding these monophyly constraints improved agreement with reference phylogenies relative to enforcing the unmodified taxonomy. By identifying groups whose monophyly should not be assumed, TaxaAudit lets researchers draw on published phylogenetic knowledge without reviewing the specialist literature for every taxon. This supports broader use of the NCBI taxonomy as an evolutionary framework for biological comparisons.

evolutionary biology↗

bioRxiv2026

Shared landscape, divergent genomes: Comparative population genomics of co-occurring flora in an isolated Australian mountain range

Understanding how landscape heterogeneity shapes genomic variation is key to conserving biodiversity and evolutionary potential. Yet conservation genomics is typically conducted at the single species level, limiting our ability to identify shared genomic patterns or understand how co-occurring taxa differ in their response to common environmental gradients. We assessed spatial patterns of genomic variation and their associations with geographic and environmental features among populations of nine co-existing plant species with contrasting life-histories and ecological traits across Gariwerd, a threatened biodiversity hotspot in south-eastern Australia. All species exhibited weak overall genetic structure, although the magnitude and spatial distribution of differentiation varied among species. Despite this variation, broadly consistent spatial trends were apparent, with higher genomic divergence largely concentrated in central zones and higher genomic diversity localised in southern regions of the landscape. Significant associations between genetic differentiation and geographic distance were observed in three species, while another species showed associations with environmental distance. These findings demonstrate that coexisting species can show overlapping spatial patterns in genomic variation while differing markedly in their associations with geographic and environmental variation across the same landscape. This comparative approach provides a basis for spatial prioritisation and conservation planning, while highlighting the complex eco-evolutionary processes operating across heterogeneous landscapes.

evolutionary biology↗