Philosophical Transactions of the Royal Society B

Different plasmids exist at different copy numbers per cell, and there is an inverse relationship between a plasmids copy number and its size. Two recent studies quantified this relationship into a scaling law, but both the form and the interpretation of this law are contested. Here, I explore the issues with fitting a single law across plasmid diversity and suggest a consistent synthesis. First, I explore some potential problems with using sequencing-based estimates of copy number. Then, I discuss plasmid copy number through a series of case studies. I argue in favour of interpreting plasmid copy numbers not through a single law, but through the lens of two dominant evolutionary strategies. I suggest that small plasmids which lack active segregation mechanisms have a resulting tradeoff between plasmid inheritance and fitness cost to the host, which is responsible for an inverse relationship between copy number and size. In contrast, larger plasmids with active segregation mechanisms show a much weaker relationship, in line with evidence that their metabolic costs are dominated by the expression of specific genes rather than their size. Where plasmids in the 20-100kb range have higher copy numbers, I argue these probably arise more from selection at the level of the host cell for plasmid-associated phenotypes (e.g. antibiotic resistance) rather than from plasmid-level selection for inheritance.

Plasmids are frequently AT-rich relative to their bacterial hosts. Despite this tendency towards lower GC content, plasmid and host chromosome GC content are positively correlated across diverse collections of plasmid-host pairs. However, the evolutionary processes underlying this pattern remain unclear. The classic model of amelioration predicts that horizontally acquired DNA gradually converges on host nucleotide composition. However, because plasmids can repeatedly transfer between bacterial hosts, the opportunity for such host-associated evolution may depend on their transmission dynamics. Using 50,936 plasmid-host pairs from a public sequence database, we found that the apparent global correlation between plasmid and host chromosome GC content was largely driven by differences between bacterial species rather than within species. We therefore accounted for plasmid and host population structure when testing how plasmid mobility shaped host-associated compositional evolution. We compared two contrasting regimes: a population of 3,682 Enterobacterales plasmids distributed across diverse host backgrounds, and six long-term host-associated plasmids from a Rhizobium leguminosarum lineage with INSeq-determined gene essentiality data. In the Enterobacterales population, GC content variation was overwhelmingly explained by plasmid lineage rather than host phylogeny, and conjugative plasmids showed greater similarity to their host chromosomes than mobilisable or non-mobilisable plasmids. In the Rhizobium leguminosarum plasmids, synonymous-site composition was more similar to the host chromosome among genes required across multiple host life stages. Together, these results support a model in which plasmid mobility influences the opportunity for host-associated evolutionary processes to alter nucleotide composition.

Objective: To develop and demonstrate an agent-based modeling framework for healthcare AI adoption, using ambient clinical documentation as the calibration case. Materials and Methods: We built an agent-based model with 50,000 clinician agents, 500 organization agents, and 4 vendor agents over 104 weeks. Modeled clinicians differed by psychotype, specialty, and friction/benefit thresholds; modeled organizations progressed through deployment phases with governance delays anchored to 8-28 weeks. All cited deployment values were independently re-verified against primary sources, and the model was validated against published data from seven health systems and three benchmarks using formal goodness-of-fit metrics (RMSE, 90% predictive-interval coverage) grouped by reference class. After correcting an organization-initialization artifact, we performed a formal six-parameter re-calibration to align both the early-time trajectory and the steady-state plateau with published data. Six intervention scenarios were compared in paired simulations (n=30 realizations per scenario) using effect sizes with bootstrap intervals, and both the full intervention comparison and the Sobol sensitivity screen were re-run natively under the re-calibrated model. Global sensitivity analysis used Sobol indices (64 base samples; 1,152 parameter sets) across eight parameters. Results: Baseline simulations produced S-curve adoption trajectories with wide variability. The re-calibrated model reproduced both early-time single-site trajectories and the cross-sectional adoption plateau, covering 86% of reference-class-matched anchors at the nominal 90% level, versus 29% for the original configuration. Most intervention scenarios increased adoption; in the original configuration the combined intervention outperformed individual levers, with significant interactions confirmed by 23 factorial analysis. Re-running the analyses natively under the calibrated model both confirmed and revised these conclusions: governance remained the largest single structural lever and non-success absorbing states remained prominent, but intervention effects attenuated sharply, the combined intervention no longer reliably exceeded the best single lever at operating scale, and the leading sensitivity driver shifted from governance delay to clinician friction/edit-rate tolerance. That calibration changes which levers appear influential is itself the central methodological finding. Organizational outcomes clustered into non-success absorbing states (pilot stagnation and failure) alongside success and scaling. Conclusions: Governance delay is an explicit upstream gate in the model, so its influence reflects model architecture and should not be interpreted as a universal real-world priority. The modeled pilot stagnation state is hypothesis-generating rather than an empirical category. Agent-based modeling provides a structured framework for understanding healthcare AI adoption dynamics. The approach supports hypothesis generation and comparative scenario exploration rather than point prediction.

Why male primates invest in costly behaviours producing public goods remains debated, with two leading explanations, paternal care and reputation-based partner choice (RBPC). Using long-term data from four groups of wild vervet monkeys, we tested: (1) whether males show a bias in four protective "male services" (predator alarm calling, participation in between-group conflicts, leading river crossings and sentinelling); (2) which males contribute most; and (3) whether service provision predicts mating success during the mating season. We confirmed a male bias in all services. Consistent with the paternal care hypothesis, contributions were positively associated with past mating success, independently of rank, although potential fathers did not contribute more than non-fathers. Among non-fathers, service provision varied with rank, suggesting that newly immigrated males adjust their behaviour according to competitive state. Crucially, variation in alarm calling and between-group conflicts predicted future mating success, with between-group conflict emerging as the strongest and most consistent predictor of mating success across years and within mating seasons, whereas rank, tenure and social integration added little explanatory power. In contrast, sentinelling and leading river crossings did not reliably translate into mating benefits. Our findings indicate that male services are shaped by multiple selective pressures operating across different male career stages and that some forms of public goods provision function as signals of quality and cooperativeness to females. By directly linking cooperative investment to mating outcomes in a wild primate, this study provides rare empirical support for reputation-based partner choice beyond humans and highlights female choice as a potentially important force in the evolution of cooperation.

Abiotic and biotic environments can change in different ways that affect how populations adapt, diverge, and speciate. However, many models of speciation only examine adaptation to constant environments. We used Fishers geometric model to study adaptation and speciation in different types of changing abiotic and biotic environments. We hypothesized that, when the magnitude of environmental change is equal, fitness would be lowered more by consistently directional abiotic change and by consistently antagonistic biotic conflict. As a result, directional changes and biotic conflict would cause a greater evolutionary response through fixation of adaptive mutations, greater divergence between populations, and lower migrant or hybrid fitnesses (higher speciation potential). Increasing the directionality of abiotic change did indeed have all these effects. However, populations evolving with conflict, despite showing the expected arms-race elevation of deleterious change and evolutionary response, did not result in decreased fitness of migrants and hybrids. Two factors seem to be involved. In tug-of-war conflict, high total phenotypic change does not lead to high phenotypic divergence because the phenotypic change churns around in the same general area of trait space. With victim-exploiter (trait matching) conflict, hybrids and migrants were frequently more fit than those with other kinds of change because of escape from locally adapted antagonists. In this case, foreign genes sometimes allowed populations in conflict to generate useful variation. These results show that different kinds of ecological change can affect adaptation and the formation of new species in distinct ways and that local divergence and incompatibility do not always go hand in hand. Significance StatementAdaptation and speciation are key processes in evolution. During the process of adapting, populations genetically diverge from each other and can become incompatible, leading to new species. The tendency for populations to diverge can be different in changing environments. Changes in the environment can consist of changes in the non-living parts like temperature or elevation (the abiotic environment) or changes in the species that a population interacts with (the biotic environment). Abiotic and biotic environments are thought to change in different ways because biotic environments are evolving but abiotic ones are not. In particular, antagonistic biotic evolution can lead to arms races. We modeled how abiotic change and biotic changes from antagonistic or mutualistic interactions affect adaptation and speciation. We found that, as expected, antagonistic biotic changes led to a large amount of evolutionary divergence but surprisingly this did not lead to correspondingly large reduction in migrant or hybrid fitness. In a tug-of- war antagonistic model, this was due evolutionary churn - high change did not lead to high divergence. In a victim-exploiter (trait matching) model, migrants and hybrids between diverging populations were often better off because antagonisms were broken up. As a result of migrants and hybrids having higher fitness, antagonistic biotic interactions may result in less speciation than expected from their evolutionary arm-races.

Autistic people can find social interactions difficult to navigate, traditionally attributed to difficulties in taking others perspectives. However, we have a limited understanding of how autistic people integrate self and other information efficiently during social decision-making. We conducted four highly powered experiments (total N = 1,621) to determine whether autistic traits affect two aspects of self-other integration during social decision making: self-bias and social basis function use. Using Bayesian analyses, we found strong support for the absence of a relationship between autistic traits and either aspect of social decision making, even after controlling for potential confounds (BF01 = 32.13 for self-bias, BF01 = 7.04 for social basis function use). Our results indicate that variations along autistic traits do not impact how people prioritise self-relevant information (self-bias) or utilize compressed social patterns of interaction (social basis function use) to guide their decisions about oneself and other people. These findings nuance the conceptualisation of social-cognitive processes across autistic traits while highlighting the need for large samples to validate null effects.

The Mutational Hazard Hypothesis (MHH) predicts that reduced effective population size weakens purifying selection and promotes transposable element (TE) accumulation. Because effective population size is difficult to estimate across broad taxonomic scales, body mass, generation time, and dN/dS are often used as proxies. We analyzed TE landscapes across 167 sauropsid genomes to test whether these proxies predict genomic TE proportion consistently across phylogenetic scales. All three showed strong scale dependence. Body mass was positively associated with TE proportion across clades, but this relationship broke down within clades: only snakes retained a significant negative Pearson correlation after multiple-testing correction, whereas the corresponding phylogenetically corrected slopes were not significant. Generation time showed a strong pooled association that disappeared within every major clade in both Pearson and PGLS analyses. The pooled dN/dS-TE relationship also disappeared after accounting for body mass and generation time in a structural equation model, with a robust within-clade association retained only in turtles. Lineage-specific TE dynamics, including LTR expansion in sea snakes, were not captured by these proxies. These results show that commonly used MHH proxies mainly reflect clade-level structure rather than consistent within-lineage mechanisms.

Eponymous etymologies (i.e., organisms named after people) are prevalent in global taxonomy worldwide, across scientific and common names. The persistent usage of eponyms has been intensely debated in recent times, across various sociopolitical, applied and philosophical perspectives. However, a rigorous statistical analysis of eponyms and their enduring colonial legacies remains hitherto unexplored. Here, we use a global and spatially-explicit network analysis to examine 2416 contemporary bird eponyms (21% of all bird species on earth) and their relationships with historical European colonialism. Additionally, we develop and utilise a Colonial Exposure Index (CEI) that summarizes the geopolitical influence of various colonial empires on modern-day countries. Our results show that an overwhelming majority of bird eponyms worldwide are named after people belonging to countries where the bird species does not occur. A majority of these eponyms honor scientists, aristocrats and army officers from erstwhile colonial empires, with eponymous species descriptions peaking during colonial expansion. Importantly, our analysis highlights a positive relationship between the Colonial Exposure Index (a metric factoring the duration and area of a country colonized by a specific empire) and the number of eponymous bird species honoring persons from that specific empire. Our temporal analysis, however, shows that the use of eponyms has recently shifted towards honoring native persons and distinguished conservation champions. Overall, this study presents an important statistical examination of eponyms and their colonial legacies, thereby providing valuable context for ongoing debates on the reform or retention of eponyms worldwide.

Cooperation is foundational to complex sociality, yet presents profound evolutionary dilemmas - costs and benefits are rarely distributed evenly and the decision to collaborate or defect can involve a complex contextual calculus. These challenges are compounded when cooperation scales from pairs to groups. Group-level cooperation is fundamental to many species success, but how is it sustained and regulated in nature? One promising route to addressing this question is to examine how individuals reorganise their affiliative interactions in anticipation of group-level cooperation. We examine such pre-cooperative reorganisation using long-term data (2013-2018) from three neighbouring groups of wild chimpanzees at the Tai National Park, Cote dIvoire, who routinely cooperate as a collective to defend their territory against other groups. We found that chimpanzees adjusted the distribution of their social contacts in anticipation of risky and proactive territorial defence by forming more broadly connected, yet more diffuse, affiliative networks. Specifically, adult chimpanzees groomed and played with more group members on days of proactive territorial defence, and this pattern was temporally-sensitive, with increased affiliation occurring before, rather than after, the cooperative act. Chimpanzees accessed a broader range of partners through increased interaction efficiency by switching between more partners with shorter interactions per partner. This pattern suggests a shared evolutionary basis of dynamic social readjustment in preparation for group-level social dilemmas in hominids, potentially providing the foundation for the formalized systems of affiliation found in human societies.

Transposon insertion sequencing (Tn-seq) has become a powerful tool for assigning gene fitness and essentiality in bacteria, and has recently been extended to bacteriophages. A core but rarely examined assumption of these screens is that fitness is measured in an asocial environment, where each mutant succeeds or fails on its own. Yet many genes act socially: their products can be shared among neighbors, allowing defective mutants to be complemented in trans. In phages multiple genotypes routinely coinfect the same cell. Here we show that social interactions distort gene essentiality. Using paired quorum-sensing microarray and Tn-seq data from Pseudomonas aeruginosa, we find that quorum-sensing-regulated genes are over-represented among genes scored as non-essential, confirming that social genes are under-reported as essential. We then build a stochastic, agent-based model of phage Tn-seq across an MOI gradient, assigning each gene an intrinsic fitness effect and a complementation fraction. Complementable ("social") genes rise in frequency as MOI increases, masking their true fitness cost, whereas non-complementable ("private") genes, do not. Partitioning genes by life-cycle stage and applying a two-round high-then-low-MOI design, further separates gene functions by life cycle stage. We argue that deliberate MOI manipulation turns a confound into a tool, enabling systematic classification of phage sociality.

Conjugative plasmids drive the dissemination of antimicrobial resistance genes and other conditionally beneficial accessory genes, but otherwise inflict fitness costs on their hosts that limit their spread. These costs can be ameliorated by compensatory mutations on the chromosome, the plasmid, or both combined (combined compensation). Mutants with plasmid-borne or chromosomal compensation differ in how they spread and compete, making the location of compensation an important determinant of plasmid and antimicrobial resistance (AMR) dynamics. We collate experimental data on plasmid-host co-evolution which, albeit limited, suggest compensatory benefits differ by location and are highest for combined compensation. We develop and analyse a mathematical model of compensatory evolution, finding that the long-term location of compensation is mainly determined by the highest cost reduction. Short term, however, succession dynamics arise from differences between locations: for instance, plasmid-borne compensation spreads horizontally, initially dominates, and can even facilitate the establishment of chromosomal or combined compensation. Strong trade-offs between compensation and either resistance or conjugation render compensation non-viable, but only conjugation trade-offs are location-dependent, disadvantaging plasmid-borne compensation and generating oscillatory dynamics. Our findings suggest plasmid-borne compensation may initially accelerate AMR-plasmid spread, whereas long-term chromosomal or combined compensation may enable hosts to accumulate multiple AMR-plasmids, promoting multidrug resistance.

Integrating auditory and visual cues is a hallmark of human speech perception, yet adults from East Asian backgrounds show less reliance on visual speech than their Western counterparts. The origins of this cultural difference, however, remain unknown. To investigate whether this divergence is established early in infancy, we examined audiovisual integration in 6- to 12- month-old White Canadian (n=111) and Chinese (n=115) infants using a novel paradigm measuring their perception of the McGurk effect. Across four experiments, we found a clear developmental divergence: Canadian infants showed a stable McGurk effect from 6 months onward, whereas Chinese infants showed a more protracted developmental trajectory, a cultural pattern that was further highlighted when their integration was challenged by other-race faces. These findings provide the first direct evidence that cultural differences in multisensory speech perception are established within the first year of life, suggesting that the brains strategy for binding sight and sound is shaped by early experience, with broad implications for theories of language acquisition and developmental science.

Island biogeography is the theoretical and empirically validated expectation that an islands biodiversity is ultimately limited by its size and isolation, with larger and less isolated (from mainland communities) islands supporting greater diversity. Island biogeography is generally applied to simple metrics of diversity such as species richness (number of different species); however, fewer studies have used traits to measure biodiversity. An organisms traits -- e.g., body mass, age at sexual maturity, trophic level -- can be used to measure biodiversity and understand how ecological communities function. We quantified species richness for birds, mammals, reptiles, and amphibians, and functional diversity for birds and mammals (for which sufficient trait data were available), and tested whether this diversity can be predicted using the theory of island biogeography. We identified 9,103 Australian islands, of which 1,661 had at least one (native and/or non-native) non-marine species present according to the Atlas of Living Australia. As expected, tetrapod species richness (S) increased with island area (A) (z = 0.299 {+/-} 0.012) following a typical power-law relationship (i.e., S = cAz, where z = 0.2-0.4), but was not predicted by distance from mainland -- consistent with the pattern observed on other recently (< 10,000 years) isolated continental islands. We found that trait richness increased at the same rate with island area as species richness for mammals, but for birds, trait richness increased more slowly than species richness. Trait turnover increased modestly with inter-island distance, whereas trait nestedness was unrelated to distance. Trait richness increased strongly with species richness in both birds and mammals, and island area and isolation explained no additional variation in functional richness after accounting for species richness. These results indicate that island geography influences functional diversity primarily through species accumulation, rather than through direct effects on occupied trait space. Overall, the trait space of smaller islands tended to be nested within that of larger, nearby islands; the main differences among similar-sized islands are due to turnover (change in species/trait combinations among assemblages), and the effects are more pronounced in mammals compared to birds. We also found evidence for an asymptotic relationship between trait and species turnover in both birds and mammals, suggesting close coupling between taxonomic and functional turnover, with some saturation of trait turnover at high species turnover. Large islands that are simultaneously more isolated might offer conservation advantages by reducing the influence of threatening processes on the mainland if distance limits access of people and invasive species.

Rapid evolution allows populations to persist in environments where they would otherwise go extinct. This phenomenon, known as evolutionary rescue, is typically studied in the framework of biological evolution, yet adaptive traits can also arise and spread through cultural evolution. The present study developed a stochastic eco-evolutionary model to compare rescue probabilities through biological and cultural evolution. Transmission bias governed the rescue probability under cultural evolution by setting how readily a rare adaptive trait was copied. Conformity bias suppressed population persistence because a rare trait was the least likely to be copied. Content bias toward the adaptive trait enabled evolutionary rescue when social learning was rapid, but it typically yielded a lower rescue probability than biological evolution. Only anticonformity bias, together with a high social learning rate, exceeded the rescue probability of biological evolution by enabling the adaptive trait to be established more rapidly. These results demonstrate that transmission bias alters the demographic consequences of cultural evolution and highlight the importance of transmission processes in evolutionary rescue theory. Understanding how adaptive behaviours are socially transmitted may also improve predictions of animal population persistence and inform conservation efforts in rapidly changing environments.

Anthropogenic climate change is threatening global biodiversity, with sea turtles particularly vulnerable as offspring sex and developmental success are strongly influenced by incubation temperature. Behavioral plasticity, including the seasonal distribution of reproductive output, may provide short-term mechanisms for mitigating these impacts. Here, we investigated season-wide hatchling sex ratios and emergence success in a small population of green turtles (Chelonia mydas), tracking individual females across their nesting seasons. Sex ratios varied markedly through the nesting season, with later nests producing a greater proportion of male hatchlings. Moreover, sex ratios were relatively consistent among nests laid by individual females. Overall, females producing more nests over a season also produced more male offspring, suggesting that both nesting phenology and reproductive output influence individual contributions to future population demographics. Mechanistic models indicate that hatchling sex ratios have trended towards female-biased ratios (>80% female) over the past 50 years, and are projected to approach complete feminization by 2100 under continued warming. Although emergence success currently remains high (>85%), it is predicted to decline sharply after mid-century, with viable hatchling production falling to [~]30% by the end of the century. Models further show that maintaining contemporary sex ratios and emergence success will require unrealistically large delays in nesting phenology, and that even extreme shifts in phenology become ineffective by 2100. Together, these findings demonstrate that individual females can increase male hatchling production by nesting later and producing more nests, but behavioral plasticity alone is unlikely to offset the accelerating impacts of climate change on this population.

As the vast majority of archival data is short-read based, reliable strategies for detecting and classifying plasmids out of these data are still needed. A widely adopted solution for binning plasmids with rich contextual data is MOB-Suite. However, a large portion of the available data has low coverage and results in fragmented assemblies. Under these circumstances, MOB-Suite delivers a high number of false positives, leading to wasteful follow-up experiments. To improve the reliability of MOB-Suite, while retaining and enriching its biological contextual output, we have developed PLAGUE. PLAGUE is a fast and low-memory consumption post-processing tool for MOB-Suite outputs, relying on checks of circularity, reads spanning the gap between the 3 and 5 ends and total coverage of the plasmid candidate. PLAGUE can reduce the number of false positives in MOB-Suite outputs by over 30%, while retaining almost full sensitivity. It is fully containerized and easy to use in clusters as well as locally.

Marine species inhabit a three-dimensional stratified environment where metabolism is simultaneously influenced by decreasing temperature and increasing hydrostatic pressure with ocean depth. While the Metabolic Theory of Ecology (MTE) incorporates the effects of body mass and temperature, for marine organisms it neglects one of the fundamental thermodynamic state variables governing biochemical reaction kinetics: hydrostatic pressure. We derive a generalized metabolic theory by extending MTE with transition-state theory by explicitly incorporating pressure sensitivity into the Arrhenius formulation. The resulting model predicts that hydrostatic pressure increases the effective activation energy of biochemical reactions, leading to progressively lower metabolic rates with increasing depth. We tested this prediction using a global database comprising 689 metabolic measurements across 11 marine phyla and 22 taxonomic classes. Incorporating hydrostatic pressure substantially improved model performance relative to the classical MTE. Across major marine taxa, activation energy and activation volume varied largely independently, suggesting that pressure adaptation does not require corresponding changes in thermal sensitivity. Our results suggest that hydrostatic pressure is a fundamental thermodynamic constraint that regulates the pace of life across the ocean and consequently the ecological dynamics across Earths largest biome.

Gradual environmental stress may trigger abrupt tipping points, trapping ecosystems in degraded states that are difficult to reverse. This possibility has strongly influenced ecosystem management, yet empirical evidence for such behavior remains mixed. A major unresolved question is how broadly stochasticity and heterogeneity restrict hysteresis, and whether their effects accumulate. To address it, we reconstructed full phase diagrams for four canonical ecological models (dryland desertification, grazing, insect outbreaks, and lake eutrophication) across gradients of stress, demographic stochasticity, environmental fluctuations, spatial heterogeneity, and dispersal. In every model, stochasticity and heterogeneity narrowed the region supporting alternative stable states and made the remaining transition less abrupt. Dispersal set their effective strength by averaging across space. These complexities eroded hysteresis along different routes -toward the degraded state, through a continuous transition, or, counterintuitively, toward the healthy state. Effects were largely additive, so several moderate complexities could eliminate hysteresis even when no single factor did. Tipping-point claims should therefore be tested under stochastic, heterogeneous conditions.

Registered Reports are a publication format designed to reduce publication bias by guaranteeing publication before results are known. This guarantee is considered attractive in the prevailing publish or perish culture. But would researchers always prefer such a low-risk option? When strong results allow publication in prestigious journals, the results-dependent nature of standard publications can actually be an advantage for authors. Given this trade-off, the choice between publication formats represents decision making under risk, and researchers may not always be risk-averse. To better understand under which circumstances Registered Reports are likely to be popular, we draw on risk-sensitivity theory from behavioural ecology and develop an agent-based model that explores how four factors shape publication strategies: whether additional publications yield diminishing or increasing career returns, the pace at which studies are completed, publication targets, and competition. We find that many realistic configurations lead researchers to avoid Registered Reports, even when Registered Reports are nearly as valuable as the best possible standard publication. Intense competition and low empirical pace can make the format unviable, while high empirical pace attenuates most other effects. Given prevailing career incentives in many fields, these results suggest that the market share of Registered Reports may remain trivially low without additional incentives or interventions.

Holocentric chromosomes allow rapid genome changes through chromosomal rearrangements such as fissions, fusions, inversions or translocations. The plant genus Carex shows one of the highest rates of karyotypic evolution among holocentric organisms. We studied the genomic patterns underlying chromosomal rearrangements in the karyotypic radiation of the narrow endemic species Carex helodes (2n = 68-75). Comparing genome assemblies of C. helodes from the two karyologically distinct extremes of its European distribution, revealed a striking number of eight chromosomal rearrangements including fusions, translocations and inversions. Genomic breakpoints are gene-poor and TE-rich, corroborating findings in other species and suggesting common genomic characteristics that facilitate the evolution and establishment of chromosomal rearrangements. We identified a chromosomal inversion exhibiting patterns of purifying selection and enrichment in functional genes that potentially mediate rearrangement tolerance. Conversely, another inversion displayed elevated sequence divergence and enrichment in response to temperature stress and phosphate limitation, matching key environmental variables that differ between the study localities. The establishment of chromosomal rearrangements along Carex helodes European populations was likely driven by demographic bottlenecks and distinct genomic features at breakpoints. Our findings provide preliminary evidence on the rearrangement role in population differentiation either as reproductive barriers or as genomic islands of differentiation.