Evolutionary Outcomes Research Articles

The emerging importance of cross-ploidy hybridisation and introgression.

Natural hybridisation is now recognised as pervasive in its occurrence across the Tree of Life. Resurgent interest in natural hybridisation fuelled by developments in genomics has led to an improved understanding of the genetic factors that promote or prevent species cross-mating. Despite this body of work overturning many widely held assumptions about the genetic barriers to hybridisation, it is still widely thought that ploidy differences between species will be an absolute barrier to hybridisation and introgression. Here, we revisit this assumption, reviewing findings from surveys of polyploidy and hybridisation in the wild. In a case study in the British flora, 203 hybrids representing 35% of hybrids with suitable data have formed via cross-ploidy matings, while a wider literature search revealed 59 studies (56 in plants and 3 in animals) in which cross-ploidy hybridisation has been confirmed with genetic data. These results show cross-ploidy hybridisation is readily overlooked, and potentially common in some groups. General findings from these studies include strong directionality of hybridisation, with introgression usually towards the higher ploidy parent, and cross-ploidy hybridisation being more likely to involve allopolyploids than autopolyploids. Evidence for adaptive introgression across a ploidy barrier and cases of cross-ploidy hybrid speciation shows the potential for important evolutionary outcomes.

Evolutionary graph theory beyond pairwise interactions: Higher-order network motifs shape times to fixation in structured populations.

To design population topologies that can accelerate rates of solution discovery in directed evolution problems or for evolutionary optimization applications, we must first systematically understand how population structure shapes evolutionary outcome. Using the mathematical formalism of evolutionary graph theory, recent studies have shown how to topologically build networks of population interaction that increase probabilities of fixation of beneficial mutations, at the expense, however, of longer fixation times, which can slow down rates of evolution, under elevated mutation rate. Here we find that moving beyond dyadic interactions in population graphs is fundamental to explain the trade-offs between probabilities and times to fixation of new mutants in the population. We show that higher-order motifs, and in particular three-node structures, allow the tuning of times to fixation, without changes in probabilities of fixation. This gives a near-continuous control over achieving solutions that allow for a wide range of times to fixation. We apply our algorithms and analytic results to two evolutionary optimization problems and show that the rate of solution discovery can be tuned near continuously by adjusting the higher-order topology of the population. We show that the effects of population structure on the rate of evolution critically depend on the optimization landscape and find that decelerators, with longer times to fixation of new mutants, are able to reach the optimal solutions faster than accelerators in complex solution spaces. Our results highlight that no one population topology fits all optimization applications, and we provide analytic and computational tools that allow for the design of networks suitable for each specific task.

An Anarchist Archaeology of Equality: Pasts and Futures Against Hierarchy

Scholars of the past frame the ‘origins’ or evolution of inequality, usually using archaeological or anthropological evidence as a basis for their arguments, as an intentional, inevitable, important step towards the development of states, implicitly framed as the pinnacle of human political and economic achievement. Anarchist archaeologies reject the idea of hierarchy as a positive or inevitable evolutionary outcome underlying the path to civilization. We argue instead for a radical reorientation towards archaeologies of equality. We propose a prefigurative archaeology that celebrates the myriad ways that human beings have actively undermined and resisted hierarchical social arrangements. We aim to reorient archaeology's focus towards societies that purposefully prevented or constrained the emergence of inequality. To demonstrate the potential of archaeologies of equality we present case examples from Oceania, Britain, West Asia and the American Southwest. Highlighting the accomplishments of societies of equals in the past demonstrates the contingency and problematic nature of present forms of inequality. It allows us to explore a different set of pasts and thus enact different presents as we imagine different futures.

Plasticity, symbionts and niche construction interact in shaping dung beetle development and evolution.

Developmental plasticity is an important product of evolutionary processes, allowing organisms to maintain high fitness in the face of environmental perturbations. Once evolved, plasticity also has the potential to influence subsequent evolutionary outcomes, for example, by shaping phenotypic variation visible to selection and facilitating the emergence of novel trait variants. Furthermore, organisms may not just respond to environmental conditions through plasticity but may also actively modify the abiotic and (sym)biotic environments to which they themselves respond, causing plasticity to interact in complex ways with niche construction. Here, we explore developmental mechanisms and evolutionary consequences of plasticity in horned dung beetles. First, we discuss how post-invasion evolution of plasticity in an introduced Onthophagus species facilitated rapid range expansion and concurrent local adaptation of life history and morphology to novel climatic conditions. Second, we discuss how, in addition to plastically responding to variation in nutritional conditions, dung beetles engage in behaviors that modify the environment that they themselves respond to during later development. We document that these environment-modifying behaviors mask heritable variation for life history traits within populations, thereby shielding genetic variants from selection. Such cryptic genetic variation may be released and become selectable when these behaviors are compromised. Together, this work documents the complex interactions between plasticity, symbionts and niche construction, and highlights the usefulness of an integrative Eco-Evo-Devo framework to study the varied mechanisms and consequences of plasticity in development and evolution.

A non-canonical nucleophile unlocks a new mechanistic pathway in a designed enzyme

Directed evolution of computationally designed enzymes has provided new insights into the emergence of sophisticated catalytic sites in proteins. In this regard, we have recently shown that a histidine nucleophile and a flexible arginine can work in synergy to accelerate the Morita-Baylis-Hillman (MBH) reaction with unrivalled efficiency. Here, we show that replacing the catalytic histidine with a non-canonical Nδ-methylhistidine (MeHis23) nucleophile leads to a substantially altered evolutionary outcome in which the catalytic Arg124 has been abandoned. Instead, Glu26 has emerged, which mediates a rate-limiting proton transfer step to deliver an enzyme (BHMeHis1.8) that is more than an order of magnitude more active than our earlier MBHase. Interestingly, although MeHis23 to His substitution in BHMeHis1.8 reduces activity by 4-fold, the resulting His containing variant is still a potent MBH biocatalyst. However, analysis of the BHMeHis1.8 evolutionary trajectory reveals that the MeHis nucleophile was crucial in the early stages of engineering to unlock the new mechanistic pathway. This study demonstrates how even subtle perturbations to key catalytic elements of designed enzymes can lead to vastly different evolutionary outcomes, resulting in new mechanistic solutions to complex chemical transformations.

Constitutive expression of the Type VI Secretion System carries no measurable fitness cost in Vibrio cholerae.

The Type VI Secretion System (T6SS) is a widespread and highly effective mechanism of microbial warfare; it confers the ability to efficiently kill susceptible cells within close proximity. Due to its large physical size, complexity, and ballistic basis for intoxication, it has widely been assumed to incur significant growth costs in the absence of improved competitive outcomes. In this study, we precisely examine the fitness costs of constitutive T6SS firing in the bacterium Vibrio cholerae. We find that, contrary to expectations, constitutive expression of the T6SS has a negligible impact on growth, reducing growth fitness by 0.025 ± 0.5% (95% CI) relative to a T6SS- control. Mathematical modeling of microbial populations demonstrates that, due to clonal interference, constitutive expression of the T6SS will often be neutral, with little impact on evolutionary outcomes. Our findings underscore the importance of precisely measuring the fitness costs of microbial social behaviors and help explain the prevalence of the T6SS across Gram-negative bacteria.

Evolutionary Accounts of Religion within a Christian Account of Big History

Big History is a mode of thought that seeks to integrate findings of the natural sciences, social sciences, and history into a coherent overarching story of the universe and of humanity. The humanity-related elements in Big History will necessarily include the emergence of "religion," including Evolutionary Accounts of Religion (EAR). Here we review two programmatic contributions to EAR, by Dunbar and Torrey, and then propose a theistic account of Big History through which to respond to their proposals. We accept their general argument that humanity's religious capacities have emerged through the evolutionary history of the Homo genus, yet we offer a theistic alternative to their accounts of the evolutionary function of religion. We then argue for how one aspect of humanity's evolved religious capacities, namely the proclivity of the Homo sapiens brain to produce transcendent ambiguity (many gods, etc.), reflects not a flaw in God's design but an evolutionary outcome intended by God--to facilitate humanity's search for God.

Reputation-based synergy and discounting mechanism promotes cooperation

A good group reputation often facilitates more efficient synergistic teamwork in production activities. Here we translate this simple motivation into a reputation-based synergy and discounting mechanism in the public goods game. Specifically, the reputation type of a group, either good or bad determined by a reputation threshold, modifies the nonlinear payoff structure described by a unified reputation impact factor. Results show that this reputation-based incentive mechanism could effectively promote cooperation compared with linear payoffs, despite the coexistence of synergy and discounting effects. Notably, the complicated interactions between reputation impact and reputation threshold result in a sharp phase transition from full cooperation to full defection. We also find that the presence of a few discounting groups could increase the average payoffs of cooperators, leading to an interesting phenomenon that when the reputation threshold is raised, the gap between the average payoffs of cooperators and defectors increases while the overall payoff decreases. We further extend our framework to heterogeneous situations and show how the variability of individuals affect the evolutionary outcomes. Our work provides important insights into facilitating cooperation in social groups.

Evolutionary Accounts of Religion within a Christian Account of Big History

Big History is a mode of thought that seeks to integrate findings of the natural sciences, social sciences, and history into a coherent overarching story of the universe and of humanity. The humanity-related elements in Big History will necessarily include the emergence of "religion," including Evolutionary Accounts of Religion (EAR). Here we review two programmatic contributions to EAR, by Dunbar and Torrey, and then propose a theistic account of Big History through which to respond to their proposals. We accept their general argument that humanity's religious capacities have emerged through the evolutionary history of the Homo genus, yet we offer a theistic alternative to their accounts of the evolutionary function of religion. We then argue for how one aspect of humanity's evolved religious capacities, namely the proclivity of the Homo sapiens brain to produce transcendent ambiguity (many gods, etc.), reflects not a flaw in God's design but an evolutionary outcome intended by God--to facilitate humanity's search for God.

ASPECTS CLINIQUES ET EVOLUTIFS DU CHOC SEPTIQUE EN REANIMATION DU CHU ANDOHATAPENAKA

Introduction: Septic shock is a major problem in intensive care units because it is responsible for high mortality. We aim to describe septic shocks clinical, bacteriological, therapeutic, and outcome aspects in the Intensive Care Department of Andohatapenaka University Hospital. Methods: This is a 30-month retrospective descriptive study of patients admitted with septic shock to the intensive care unit of CHU Andohatapenaka. The parameters studied were sociodemographic data, clinical parameters, bacteriological parameters, and evolutionary outcomes. Results: The incidence of septic shock was 9.5%. The mean age was 59±15 years. Male predominance was 65.8%, with a sex ratio of 1.9. Hypertension was the main comorbidity (64.3%). Disturbed consciousness was the most common reason for admission (41.5%). Polypnoea was found in 92.7% of patients. Pulmonary infection was predominant in 78.1% of cases. In this study, 34.2% had undergone bacteriological sampling. Kochs bacillus (9.7%) and Gram-negative bacilli (12.2%) predominated among the germs found. All patients received vascular filling, vasopressors, oxygen therapy, and antibiotic treatment. In this study, 39% of patients received mechanical ventilation. The mortality rate was 73.1%. Conclusion: Septic shock is still a real public health problem. It is the leading cause of death in intensive care. A further study will be necessary to determine the predictive factors of septic shock to improve management.

Changes in capture availability due to infection can lead to detectable biases in population-level infectious disease parameters.

Correctly identifying the strength of selection that parasites impose on hosts is key to predicting epidemiological and evolutionary outcomes of host-parasite interactions. However, behavioral changes due to infection can alter the capture probability of infected hosts and thereby make selection difficult to estimate by standard sampling techniques. Mark-recapture approaches, which allow researchers to determine if some groups in a population are less likely to be captured than others, can be used to identify infection-driven capture biases. If a metric of interest directly compares infected and uninfected populations, calculated detection probabilities for both groups may be useful in identifying bias. Here, we use an individual-based simulation to test whether changes in capture rate due to infection can alter estimates of three key metrics: 1) reduction in the reproductive success of infected parents relative to uninfected parents, 2) the relative risk of infection for susceptible genotypes compared to resistant genotypes, and 3) changes in allele frequencies between generations. We explore the direction and underlying causes of the biases that emerge from these simulations. Finally, we argue that short series of mark-recapture sampling bouts, potentially implemented in under a week, can yield key data on detection bias due to infection while not adding a significantly higher burden to disease ecology studies.

Digest: The importance of genetic background in bacterial evolution.

How does genetic background influence a population's evolutionary response to an environmental change? Which traits are selected for and how quickly does the population adapt? Filipow et al. (2024) address these questions by exploiting the natural genetic variation of Pseudomonas aeruginosa, a bacterium often found in the lungs of cystic fibrosis patients. They find that while genetic background influences the rate of phenotypic evolution, it does not alter the evolutionary outcome. Their findings contribute to a growing body of work that connects genetic background to future evolvability.

Evolution of parental care in haploid-diploid plants.

In bryophytes that alternate between haploid gametophytes and diploid sporophytes through sexual reproduction, sporophytes are often attached to and nurtured on the female gametophyte. A similar phenomenon is seen in Florideophyceae (a group of red algae). These systems in which a gametophyte (mother) invests nutrients in sporophytes (offspring) are ideal for studying the evolution of 'parental care' in non-animal organisms. Here, we propose a model of a haploid-diploid life cycle and examine the evolution of maternal investment in sporophytes focusing on two effects: the degree of paternal or maternal control of investment and the number of sporophytes. We find that when the female dominantly controls the investment, the evolutionarily stable level of investment is that which maximizes the expected reproductive success of the female gametophyte. The genomic conflict between maternal and paternal alleles complicates the evolutionary outcome; however, a greater male allelic effect and a higher number of sporophytes favour a higher energy investment, which may lead to evolutionary branching or run-away escalation of the investment level. This suggests that the selfishness of the paternal gene is the evolutionary driver of parental care and that complex structures such as fusion cells in red algae may have evolved to suppress it.

Darwin review: the evolution of virulence in human pathogens.

By definition, all pathogens cause some level of harm to their hosts. If this harm occurs while the pathogen is transmitting, it can negatively affect the pathogen's fitness by shortening the duration over which transmission can occur. However, many of the factors that increase virulence (i.e. harm to host) also promote transmission, driving the pathogen population towards an optimal state of intermediate virulence. A wider spectrum of virulence may be maintained among pathogen populations which are structured into multiple discrete strains though direct resource and immune-mediated competition. These various evolutionary outcomes, and the effects of medical and public health interventions, are best understood within a framework that recognizes the complex relationship between transmission and virulence in the context of the antigenic diversity of the pathogen population.

Morphological ant mimics: constrained to imperfection?

Adaptive evolution relies on both heritable variation and selection. Variation is the raw material upon which selection acts, so any mechanism that limits or prevents the generation of heritable variation reduces the power of selection to lead to adaptation. Such limitations are termed evolutionary constraints. While it is widely accepted that constraints play an important role in shaping evolutionary outcomes, their relative importance, as opposed to adaptation, in determining evolutionary outcomes remains a subject of debate. Evolutionary constraints are often evoked as the reason behind the persistence of inaccurate mimicry. Here, we compared the variation and accuracy of body-shape mimicry in ant-mimicking spiders with that of ant-mimicking insects, predicting greater constraints, and hence inaccuracy, in spiders mimicking ants, due to their evolutionary distance from the ant model. We found high inter-species variation in mimetic accuracy, but dorsally, no overall difference in mimetic accuracy between spider and insect mimics, which is inconsistent with a constraint causing inaccurate mimicry. Our study provides empirical evidence suggesting that imperfect mimicry in spiders and insects is predominantly shaped by adaptive processes rather than constraints or chance. Our findings contribute to our understanding of the mechanisms underlying evolutionary diversity and the processes that shape phenotypic outcomes.

Effects of group size and population size on the evolutionary stability of cooperation

Evolutionary game theory has classically been developed under the implicit assumption of an infinite population. Exact analytical results for finite populations are rare, and those that exist apply to situations in which strategy sets are discrete. We rigorously analyse a standard model for the evolution of cooperation (the multi-player continuous-strategy snowdrift game) and show that in many situations in which there is a cooperative evolutionarily stable strategy (ESS) if the population is infinite , there is no cooperative ESS if the population is finite (no matter how large). In these cases, contributing nothing is a globally convergently stable finite-population ESS, implying that apparent evolution of cooperation in such games is an artefact of the infinite population approximation. The key issue is that if the size of groups that play the game exceeds a critical proportion of the population then the infinite-population approximation predicts the wrong evolutionary outcome (in addition, the critical proportion itself depends on the population size). Our results are robust to the underlying selection process.

Genomic architecture controls multivariate adaptation to climate change.

As climate change advances, environmental gradients may decouple, generating novel multivariate environments that stress wild populations. A commonly invoked mechanism of evolutionary rescue is adaptive gene flow tracking climate shifts, but gene flow from populations inhabiting similar conditions on one environmental axis could cause maladaptive introgression when populations are adapted to different environmental variables that do not shift together. Genomic architecture can play an important role in determining the effectiveness and relative magnitudes of adaptive gene flow and insitu adaptation. This may have direct consequences for how species respond to climate change but is often overlooked. Here, we simulated microevolutionary responses to environmental change under scenarios defined by variation in the polygenicity, linkage, and genetic redundancy of two independent traits, one of which is adapted to a gradient that shifts under climate change. We used these simulations to examine how genomic architecture influences evolutionary outcomes under climate change. We found that climate-tracking (up-gradient) gene flow, though present in all scenarios, was strongly constrained under scenarios of lower linkage and higher polygenicity and redundancy, suggesting insitu adaptation as the predominant mechanism of evolutionary rescue under these conditions. We also found that high polygenicity caused increased maladaptation and demographic decline, a concerning result given that many climate-adapted traits may be polygenic. Finally, in scenarios with high redundancy, we observed increased adaptive capacity. This finding adds to the growing recognition of the importance of redundancy in mediating insitu adaptive capacity and suggests opportunities for better understanding the climatic vulnerability of real populations.

Evolutionary game analysis of online game studios and online game companies participating in the virtual economy of online games.

In the context of the new economic development in the post-pandemic era, "play" labor as an important component of digital work has become an inexhaustible driving force for the growth of the digital economy. Previous research has shown that "play" labor, as an emerging business model, can effectively promote the growth of the digital economy. However, there is a relative lack of research on the dynamic evolutionary game between "play" labor suppliers represented by game studios and online gaming companies. In this study, we applied the theoretical approach of dynamic evolutionary game theory to establish a game model depicting the evolution of both parties involved in the virtual economy of online gaming. The aim was to investigate the strategic selection mechanisms and influencing factors for game studios and online gaming companies participating in the virtual economy of online gaming. By analyzing the evolutionary game path, equilibrium points, and factors influencing the evolutionary game outcome, as well as conducting numerical simulation analysis using Matlab software, we found that the incremental gains and costs resulting from the strategic choices of online gaming companies and game studios in engaging in the virtual economy of online gaming affect the evolutionary outcomes. In addition, for the probability ratio of online game studios and online game companies choosing to participate in the virtual economy of online games, whether it is online game studios or online game companies, the larger the initialization ratio, the more likely the evolution result is to develop in a mutually beneficial direction. After an in-depth analysis and discussion of the evolutionary game results, relevant policy recommendations were proposed. We hope to provide a reference for promoting online game companies to strengthen the adequate supervision of online game studios' participation in the virtual economy of online games and optimize and improve the virtual economic environment.

Firms’ corporate social irresponsibility behaviors during interplay with consumers in evolutionary game models

We employ an evolutionary game model to investigate the interaction between firms’ engagement in corporate social irresponsibility (CSI) behaviors (without violating laws) and consumers’ perception of corporate social responsibility (CSR) within a consumer market. The core paradox revolves around the trade-off between firms benefiting from pursuing economic performance without adhering to social responsibility and the maximization of social welfare achieved when firms are socially responsible, and consumers possess strong CSR perception. Through an asymmetric two-population evolutionary game model, we identify two distinct scenarios of evolutionary stable strategies based on different industrial environments. Additionally, the evolution of a healthy market is contingent upon an increase in consumers’ bargaining power, although it is also influenced by the initial states of the two-group system, resulting in path dependence as a significant feature of the system’s evolutionary equilibrium. Furthermore, we observe that the added willingness to pay for CSR, while not impacting the evolutionary outcomes, could increase the likelihood of a healthy market when consumers’ bargaining power is high. These findings underscore the diverse dynamics of firms’ CSI behaviors, which depend on transaction costs, industrial structure, and consumers’ willingness to pay, offering valuable insights from a micro perspective.

The Evolution Path and Impact Mechanism of the Vulnerability of Rural Human Settlements in China under the Background of Globalization

Development in the rural environment is a key pillar motivating international organizations' functions and operations. The development in this area falls under the 2030 Agenda of Sustainable Development of the UN. Rural development and factors such as culture might be utilized to achieve such agenda and improve populations living in conditions. The current study was literature systemic reviewing the evolution path and the impact mechanism on the issue of rural human settlement. Results in the current study showed that natural ecosystems, socioeconomic systems, facilities, and service systems all follow one of seven general evolution paths. Terrain and ecology, climate change and catastrophe, the agricultural and rural economy, population increase, and other factors all contribute to disruption. Policy, technology, and the habits of individual households inform the development of action plans. Every evolutionary outcome has both fragile and hardy features. The government and individual families took measures to lower vulnerability and increase resilience by concentrating on the actual problem of the rural human settlements system. Further, the study observed that the effects of rural human settlements on rural development occur in a systematic way. These changes, most obviously seen in the form of new and improved rural human settlement projects, have the potential to affect many facets of the human settlement system as a whole, making it cleaner, more practical, more harmonic, and generally more pleasant places to live. These benefits will have a multiplicative impact on the health, wealth, and happiness of rural residents; the efficiency, modernity, and prosperity of rural businesses; and the quality of life in rural areas.