Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “evolutionary dynamics”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 739 records · Page 41Linked to original sources
PubMed2003

Evolutionarily stable sets in the single-locus frequency-dependent model of natural selection.

Recent developments in the static theory of evolutionarily stable sets (ESSets) are applied to the single-locus frequency-dependent model of natural selection. Particular emphasis is paid to the ESSet properties of the preimage of an ESS (or ESSet) under the genotype-phenotype map. When an ESS is realized in genetic equilibrium with redundancy in a diploid sexual population, the basic problem in biological terms is whether the corresponding set of allele frequencies is an evolutionarily stable set. The interesting question of the dynamic stability of this preimage is also discussed and a geometric condition developed which implies its evolutionary and dynamic stability.

Alleles↗
PubMed2003

Developmental dynamics: toward a biologically plausible evolutionary psychology.

There has been a conceptual revolution in the biological sciences over the past several decades. Evidence from genetics, embryology, and developmental biology has converged to offer a more epigenetic, contingent, and dynamic view of how organisms develop. Despite these advances, arguments for the heuristic value of a gene-centered, predeterministic approach to the study of human behavior and development have become increasingly evident in the psychological sciences during this time. In this article, the authors review recent advances in genetics, embryology, and developmental biology that have transformed contemporary developmental and evolutionary theory and explore how these advances challenge gene-centered explanations of human behavior that ignore the complex, highly coordinated system of regulatory dynamics involved in development and evolution.

Biological Evolution↗
PubMed2002

The adaptive dynamics of Lotka-Volterra systems with trade-offs.

We analyse the adaptive dynamics of a generalised type of Lotka-Volterra model subject to an explicit trade-off between two parameters. A simple expression for the fitness of a mutant strategy in an environment determined by the established, resident strategy is obtained leading to general results for the position of the evolutionary singular strategy and the associated second-order partial derivatives of the mutant fitness with respect to the mutant and resident strategies. Combinations of these results can be used to determine the evolutionary behaviour of the system. The theory is motivated by an example of prey evolution in a predator-prey system in which results show that only (non-EUS) evolutionary repellor dynamics, where evolution is directed away from a singular strategy, or dynamics where the singular strategy is an evolutionary attractor, are possible. Moreover, the general theory can be used to show that these results are the only possibility for all Lotka-Volterra systems in which aside from the trade-offs all parameters are independent and in which the interaction terms are of quadratic order or less. The applicability of the theory is highlighted by examining the evolution of an intermediate predator in a tri-trophic model.

Adaptation, Biological↗
PubMed2004

War of attrition with implicit time cost.

In the game-theoretic model war of attrition, players are subject to an explicit cost proportional to the duration of contests. We construct a model where the time cost is not explicitly given, but instead depends implicitly on the strategies of the whole population. We identify and analyse the underlying mechanisms responsible for the implicit time cost. Each player participates in a series of games, where those prepared to wait longer win with higher certainty but play less frequently. The model is characterized by the ratio of the winner's score to the loser's score, in a single game. The fitness of a player is determined by the accumulated score from the games played during a generation. We derive the stationary distribution of strategies under the replicator dynamics. When the score ratio is high, we find that the stationary distribution is unstable, with respect to both evolutionary and dynamical stability, and the dynamics converge to a limit cycle. When the ratio is low, the dynamics converge to the stationary distribution. For an intermediate interval of the ratio, the distribution is dynamically but not evolutionarily stable. Finally, the implications of our results for previous models based on the war of attrition are discussed.

Animals↗
PubMed2005

Mycobacterium tuberculosis molecular evolution in western Mediterranean Islands of Sicily and Sardinia.

In this study, a total of 204 Mycobacterium tuberculosis DNAs from Sicily (n = 144) and Sardinia (n = 60) were studied by three genotyping methods. Results were analyzed both within and across islands, to define the phylogeographical specificities of the genotypes, look for their diversity and infer a molecular evolutionary scenario. A strong link between geography and tuberculosis genotypes was observed in Sardinia. The results were also matched against a world-wide genetic diversity database to compare the population structure of the tubercle bacilli in the islands. Eight common genotypes between Sicily, Sardinia and continental Italy were found which underlines the influences of the Italian mainland on the population structure on the islands and vice versa. A unified evolutionary scenario of M. tuberculosis evolution was built using numerical taxonomy and maximum parsimony (MP) methods. The finding of multiple families of M. tuberculosis strains (S, T, LAM, Haarlem), their presumed links with the major genetic groups (MGG) of M. tuberculosis complex, supports the view of independent introduction of several ancestral genotypes in Sicily and in Sardinia. We conclude that the two PCR-based genotyping combination (spoligotyping-VNTR) is an excellent tool to reconstruct M. tuberculosis phylogeny, that may be used to construct global and local evolutionary scenarios of the M. tuberculosis complex. The results obtained are paradigmatic of the complex interplay that exists between epidemic dynamics and evolutionary genetics of M. tuberculosis.

DNA, Bacterial↗
PubMed1996

Memory, sleep, and dynamic stabilization of neural circuitry: evolutionary perspectives.

Some aspects of the evolution of mechanisms for enhancement and maintenance of synaptic efficacy are treated. After the origin of use-dependent synaptic plasticity, frequent synaptic activation (dynamic stabilization, DS) probably prolonged transient efficacy enhancements induced by single activations. In many "primitive" invertebrates inhabiting essentially unvarying aqueous environments, DS of synapses occurs primarily in the course of frequent functional use. In advanced locomoting ectotherms encountering highly varied environments, DS is thought to occur both through frequent functional use and by spontaneous "non-utilitarian" activations that occur primarily during rest. Non-utilitarian activations are induced by endogenous oscillatory neuronal activity, the need for which might have been one of the sources of selective pressure for the evolution of neurons with oscillatory firing capacities. As non-sleeping animals evolved increasingly complex brains, ever greater amounts of circuitry encoding inherited and experiential information (memories) required maintenance. The selective pressure for the evolution of sleep may have been the need to depress perception and processing of sensory inputs to minimize interference with DS of this circuitry. As the higher body temperatures and metabolic rates of endothermy evolved, mere skeletal muscle hypotonia evidently did not suffice to prevent sleep-disrupting skeletal muscle contractions during DS of motor circuitry. Selection against sleep disruption may have led to the evolution of further decreases in muscle tone, paralleling the increase in metabolic rate, and culminating in the postural atonia of REM (rapid eye movement) sleep. Phasic variations in heart and respiratory rates during REM sleep may result from superposition of activations accomplishing non-utilitarian DS of redundant and modulatory motor circuitry on the rhythmic autonomic control mechanisms. Accompanying non-utilitarian DS of circuitry during sleep, authentic and variously modified information encoded in the circuitry achieves the level of unconscious awareness as dreams and other sleep mentation.

Animals↗
PubMed1992

M.V. Volkenstein, evolutionary thinking and the structure of fitness landscapes.

High dimensional fitness landscapes are robustly dominated by saddle points, not isolated peaks. We present an argument to this effect that is reminiscent of May's complexity stability analysis and trace out the significance for the dynamics of speciation, the connection between the neutral and punctuated aspects of evolution and evolution on moving landscapes. The paper is written in honor of M.V. Volkenstein (October 23rd, 1912-February 18th, 1992), who devoted his last papers to uniting dynamics with evolutionary thinking.

Biological Evolution↗
PubMed2006

The evolution of parasite manipulation of host dispersal.

We investigate the evolution of manipulation of host dispersal behaviour by parasites using spatially explicit individual-based simulations. We find that when dispersal is local, parasites always gain from increasing their hosts' dispersal rate, although the evolutionary outcome is determined by the costs-to-benefits ratio. However, when dispersal can be non-local, we show that parasites investing in an intermediate dispersal distance of their hosts are favoured even when the manipulation is not costly, due to the intrinsic spatial dynamics of the host-parasite interaction. Our analysis highlights the crucial importance of ecological spatial dynamics in evolutionary processes and reveals the theoretical possibility that parasites could manipulate their hosts' dispersal.

Adaptation, Physiological↗
PubMed1998

Modelling Coevolution in Multispecies Communities.

We introduce the Webworld model, which links together the ecological modelling of food web structure with the evolutionary modelling of speciation and extinction events. The model describes dynamics of ecological communities on an evolutionary time-scale. Species are defined as sets of characteristic features, and these features are used to determine interaction scores between species. A simple rule is used to transfer resources from the external environment through the food web to each of the species, and to determine mean population sizes. A time step in the model represents a speciation event. A new species is added with features similar to those of one of the existing species and a new food web structure is than calculated. The new species may (i) add stably to the web, (ii) become extinct immediately because it is poorly adapted, or (iii) cause one or more other species to become extinct due to competition for resources. We measure various properties of the model webs and compare these with data on real food webs. These properties include the proportions of basal, intermediate and top species, the number of links per species and the number of trophic levels. We also study the evolutionary dynamics of the model ecosystem by following the fluctuations in the total number of species in the web. Extinction avalanches occur when novel organisms arise which are significantly better adapted than existing ones. We discuss these results in relation to the observed extinction events in the fossil record, and to the theory of self-organized criticality.Copyright 1998 Academic Press

Journal Article↗
PubMed1990

On the validity of von Baer's laws in evolutionary morphology.

The validity of von Baer's "laws" on the general and the specific in vertebrate morphogenesis (especially organogenesis) was varified. The author starts from the hypothesis that the rudiments of traits newly acquired during morphogenesis are not rigid, not immovable, during morphogenesis, but that the action of protracted stabilizing selection during the geological ages causes them to spread and pushes them back to the perfected and stabilized in adulthood, thereby shortening the recapitulation of ancestral traits, which may eventually disappear below the threshold of detectable morphogenesis. On the basis of this thesis of the dynamics of evolutionary morphogenesis (the author bases his considerations on his studies of the morphogenesis of the avian carpometacarpus and the nasal apparatus in Sauropsida), the author comes to the conclusion that these von Baer's rules presuppose rigidity and immovability of phylogenetic morphogenesis. In fact, the general and the specific in evolutionary morphogenesis (especially organogenesis) is continuously motion, the general changes to the specific and the specific to the general and both categories undergo incessant changes. Von Baer's rules are thus not generally valid, they cannot rank as laws and in many cases they do not apply to morphogenesis (especially organogenesis), particularly in the transitional phase of evolutionary morphogenesis, when the rudiments of progressive evolutionary deviations have reached the early phases of morphogenesis and recapitulation has disappeared - and the "general" has also disappeared.

Animals↗
PubMed1999

The evolutionary language game.

We explore how evolutionary game dynamics have to be modified to accomodate a mathematical framework for the evolution of language. In particular, we are interested in the evolution of vocabulary, that is associations between signals and objects. We assume that successful communication contributes to biological fitness: individuals who communicate well leave more offspring. Children inherit from their parents a strategy for language learning (a language acquisition device). We consider three mechanisms whereby language is passed from one generation to the next: (i) parental learning: children learn the language of their parents; (ii) role model learning: children learn the language of individuals with a high payoff; and (iii) random learning: children learn the language of randomly chosen individuals. We show that parental and role model learning outperform random learning. Then we introduce mistakes in language learning and study how this process changes language over time. Mistakes increase the overall efficacy of parental and role model learning: in a world with errors evolutionary adaptation is more efficient. Our model also provides a simple explanation why homonomy is common while synonymy is rare.

Biological Evolution↗
PubMed2003

Subtle functional collective motions in pancreatic-like ribonucleases: from ribonuclease A to angiogenin.

The analysis of the dynamic behavior of enzymes is fundamental to structural biology. A direct relationship between protein flexibility and biological function has been shown for bovine pancreatic ribonuclease (RNase A) (Rasmussen et al., Nature 1992;357:423-424). More recently, crystallographic studies have shown that functional motions in RNase A involve the enzyme beta-sheet regions that move concertedly on substrate binding and release (Vitagliano et al., Proteins 2002;46:97-104). These motions have been shown to correspond to intrinsic dynamic properties of the native enzyme by molecular dynamics (MD) simulations. To unveil the occurrence of these collective motions in other members of pancreatic-like superfamily, we carried out MD simulations on human angiogenin (Ang). Essential dynamics (ED) analyses performed on the trajectories reveal that Ang exhibits collective motions similar to RNase A, despite the limited sequence identity (33%) of the two proteins. Furthermore, we show that these collective motions are also present in ensembles of experimentally determined structures of both Ang and RNase A. Finally, these subtle concerted beta-sheet motions were also observed for other two members of the pancreatic-like superfamily by comparing the ligand-bound and ligand-free structures of these enzymes. Taken together, these findings suggest that pancreatic-like ribonucleases share an evolutionary conserved dynamic behavior consisting of subtle beta-sheet motions, which are essential for substrate binding and release.

Animals↗
PubMed2004

Suppression of ecological competition by an apex predator.

In the framework of Lotka-Volterra dynamics with evolutionary parameter variation, it is shown that a system of two competing species which is evolutionarily unstable, if left to themselves, is stabilized by a common predator preying on both of them. Game-theoretic implications of the results are also discussed.

Adaptation, Biological↗
PubMed1987

A computer model of evolutionary optimization.

Molecular evolution is viewed as a typical combinatorial optimization problem. We analyse a chemical reaction model which considers RNA replication including correct copying and point mutations together with hydrolytic degradation and the dilution flux of a flow reactor. The corresponding stochastic reaction network is implemented on a computer in order to investigate some basic features of evolutionary optimization dynamics. Characteristic features of real molecular systems are mimicked by folding binary sequences into unknotted two-dimensional structures. Selective values are derived from these molecular 'phenotypes' by an evaluation procedure which assigns numerical values to different elements of the secondary structure. The fitness function obtained thereby contains nontrivial long-range interactions which are typical for real systems. The fitness landscape also reveals quite involved and bizarre local topologies which we consider also representative of polynucleotide replication in actually occurring systems. Optimization operates on an ensemble of sequences via mutation and natural selection. The strategy observed in the simulation experiments is fairly general and resembles closely a heuristic widely applied in operations research areas. Despite the relative smallness of the system--we study 2000 molecules of chain length v = 70 in a typical simulation experiment--features typical for the evolution of real populations are observed as there are error thresholds for replication, evolutionary steps and quasistationary sequence distributions. The relative importance of selectively neutral or almost neutral variants is discussed quantitatively. Four characteristic ensemble properties, entropy of the distribution, ensemble correlation, mean Hamming distance and diversity of the population, are computed and checked for their sensitivity in recording major optimization events during the simulation.

Base Sequence↗
PubMed2005

Population structure of Columbia spotted frogs (Rana luteiventris) is strongly affected by the landscape.

Landscape features such as mountains, rivers, and ecological gradients may strongly affect patterns of dispersal and gene flow among populations and thereby shape population dynamics and evolutionary trajectories. The landscape may have a particularly strong effect on patterns of dispersal and gene flow in amphibians because amphibians are thought to have poor dispersal abilities. We examined genetic variation at six microsatellite loci in Columbia spotted frogs (Rana luteiventris) from 28 breeding ponds in western Montana and Idaho, USA, in order to investigate the effects of landscape structure on patterns of gene flow. We were particularly interested in addressing three questions: (i) do ridges act as barriers to gene flow? (ii) is gene flow restricted between low and high elevation ponds? (iii) does a pond equal a 'randomly mating population' (a deme)? We found that mountain ridges and elevational differences were associated with increased genetic differentiation among sites, suggesting that gene flow is restricted by ridges and elevation in this species. We also found that populations of Columbia spotted frogs generally include more than a single pond except for very isolated ponds. There was also evidence for surprisingly high levels of gene flow among low elevation sites separated by large distances. Moreover, genetic variation within populations was strongly negatively correlated with elevation, suggesting effective population sizes are much smaller at high elevation than at low elevation. Our results show that landscape features have a profound effect on patterns of genetic variation in Columbia spotted frogs.

Altitude↗
PubMed2001

On the relative importance of haplodiploidy, assortative mating and social synergy on the evolutionary emergence of social behavior.

Advances in multiagent simulation techniques make it possible to study more realistic dynamics of complex systems and allow evolutionary theories to be tested. Here I use simulations to assess the relative importance of reproductive systems (haplodiploidy vs. diploidy), mate selection (assortative mating vs. random mating) and social economics (pay-off matrices of evolutionary games) in the evolutionary dynamics leading to the emergence of social cooperation in the provision of parental care. The simulations confirm that haplo-diploid organisms and organisms mating assortatively have a higher probability for fixing alleles and require less favorable conditions for their fixation, than diploids or organisms mating randomly. The simulations showed that social behavior was most likely to emerge a) when the cost for parental investment was much lower than the benefits to the offspring, b) when cooperation improved synergistically the fitness of offspring compared to the corresponding egoistic behavior and c) when alleles coding for altruistic or social behavior could be rapidly fixed in the population, thanks to mechanisms such as haplo-diploidy and/or assortative mating. Cooperative social behavior always appeared if sociality conferred much higher fitness gains compared to non cooperative alternatives suggesting that the most important factors for the emergence and maintenance of social behavior are those based on energetic or efficiency considerations. The simulations, in congruence with the scant experimental evidence available, suggest that economic considerations rather than genetic ones are critical in explaining the emergence and maintenance of sociality.

Animals↗
PubMed2006

Disease evolution across a range of spatio-temporal scales.

Traditional explorations of infectious disease evolution have considered the competition between two cross-reactive strains within the standard framework of disease models. Such techniques predict that diseases should evolve to be highly transmissible, benign to the host and possess a long infectious period: in general, diseases do not conform to this ideal. Here we consider a more holistic approach, suggesting that evolution is a trade-off between adaptive pressures at different scales: within host, between hosts and at the population level. We present a model combining within-host pathogen dynamics and transmission between individuals governed by an explicit contact network, where transmission dynamics between hosts are a function of the interaction between the pathogen and the hosts' immune system, though ultimately constrained by the contacts each infected host possesses. Our results show how each of the scales places constraints on the evolutionary behavior, and that complex dynamics may emerge due to the feedbacks between epidemiological and evolutionary dynamics. In particular, multiple stable states can occur with switching between them stochastically driven.

Communicable Diseases↗
PubMed2026

Genetic Variation and Evolutionary Characteristics of Coxsackievirus B1: F3 Subtype Associated With Hand, Foot and Mouth Disease in China.

Coxsackievirus B1 (CV-B1) is primarily associated with meningitis but can also cause localized outbreaks of hand, foot, and mouth disease (HFMD). This study analyzed the genetic diversity of the VP1 gene in 39 strains of the CVB1 virus isolated from HFMD children across 15 provinces in China between 2010 and 2024, as well as 179 strains from 17 countries. Based on the average nucleotide difference of VP1 gene, we classified CVB1 virus into six genotypes A to F, Notably, genotype F is newly classified. Since 2010, genotype F guadually replaced genotype E as the dominant genotype in China and has further subdivided into three subtypes: F1, F2, and F3, with F3 being the most prevalent subtype in China currently. We specifically study the mild and severe cases within the F3 subtype. Temperature-sensitivity experiments revealed no differences between mild and severe cases of the F3 subtype, and they all belong to temperature-sensitive strains. Interestingly, we found that mild cases of the F3 subtype did not involve recombination, whereas all severe cases of the F3 subtype showed recombination with Coxsackievirus B4 (CVB4). CVB4 has consistently been the primary pathogen responsible for severe neonatal illnesses, suggesting that recombination between the F3 subtype and CVB4 may be associated with the development of severe HFMD. These findings provide fundamental scientific data for further investigation into the epidemiology and genetic characteristics of variants of Coxsackievirus B1 in China.

Humans↗