scholarly journals Epidemiological and evolutionary consequences of periodicity in treatment coverage

2021 ◽  
Vol 288 (1946) ◽  
pp. 20203007
Author(s):  
Alicia Walter ◽  
Sébastien Lion
Keyword(s):  
Evolutionary Dynamics ◽  
Treatment Strategies ◽  
Structured Populations ◽  
Disease Spread ◽  
Reproductive Value ◽  
Selection Gradient ◽  
Treatment Coverage ◽  
Pathogen Prevalence ◽  
Evolutionary Consequences ◽  
Pulsed Treatment

Host heterogeneity is a key driver of host–pathogen dynamics. In particular, the use of treatments against infectious diseases creates variation in quality among hosts, which can have both epidemiological and evolutionary consequences. We present a general theoretical model to highlight the consequences of different imperfect treatments on pathogen prevalence and evolution. These treatments differ in their action on host and pathogen traits. In contrast with previous studies, we assume that treatment coverage can vary in time, as in seasonal or pulsed treatment strategies. We show that periodic treatment strategies can limit both disease spread and virulence evolution, depending on the type of treatment. We also introduce a new method to analytically calculate the selection gradient in periodic environments, which allows our predictions to be interpreted using the concept of reproductive value, and can be applied more generally to analyse eco-evolutionary dynamics in class-structured populations and fluctuating environments.

scholarly journals Invasion fitness for gene-culture co-evolution in family-structured populations and an application to cumulative culture under vertical transmission

2017 ◽  
Author(s):  
Charles Mullon ◽  
Laurent Lehmann
Keyword(s):  
Vertical Transmission ◽  
Evolutionary Dynamics ◽  
Structured Populations ◽  
Selection Gradient ◽  
Cultural Information ◽  
Invasion Fitness ◽  
Cumulative Cultural Evolution ◽  
Multigenerational Effects ◽  
Amount Of Knowledge ◽  
Genetically Determined

AbstractHuman evolution depends on the co-evolution between genetically determined behaviors and socially transmitted information. Although vertical transmission of cultural information from parent to off-spring is common in hominins, its effects on cumulative cultural evolution are not fully understood. Here, we investigate gene-culture co-evolution in a family-structured population by studying the invasion fitness of a mutant allele that influences a deterministic level of cultural information (e.g., amount of knowledge or skill) to which diploid carriers of the mutant are exposed in subsequent generations. We show that the selection gradient on such a mutant, and the concomitant level of cultural information it generates, can be evaluated analytically under the assumption that the cultural dynamic has a single attractor point, thereby making gene-culture co-evolution in family-structured populations with multigenerational effects mathematically tractable. We apply our result to study how genetically determined phenotypes of individual and social learning co-evolve with the level of adaptive information they generate under vertical transmission. We find that vertical transmission increases adaptive information due to kin selection effects, but when information is transmitted as efficiently between family members as between unrelated individuals, this increase is moderate in diploids. By contrast, we show that the way resource allocation into learning trades off with allocation into reproduction (the “learning-reproduction trade-off”) significantly influences levels of adaptive information. We also show that vertical transmission prevents evolutionary branching and may therefore play a qualitative role in gene-culture co-evolutionary dynamics. More generally, our analysis of selection suggests that vertical transmission can significantly increase levels of adaptive information under the biologically plausible condition that information transmission between relatives is more efficient than between unrelated individuals.

scholarly journals Basic Conceptual Structure of Evolutionary Ecology

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Rogério Parentoni Martins
Keyword(s):  
Evolutionary Biology ◽  
Evolutionary Ecology ◽  
Genotypic Variation ◽  
Structured Populations ◽  
Phenotypic Variance ◽  
Selective Agents ◽  
Survival And Reproduction ◽  
Environmental Variations ◽  
Successive Generations ◽  
Evolutionary Consequences

Concepts are linguistic structures with specific syntax and semantics used as sources of communicating ideas. Concepts can be simple (e.g., tree), complex (e.g., adaptation) and be part of a network of interactions that characterize an area of scientific research. The conceptual interrelationships and some evolutionary consequences upon which these interrelations are based will be addressed here. The evolutionary ecology is an area of research from the population evolutionary biology that deals mainly with the effect of positive natural selection on panmictic and structured populations. Environmental factors, conditions and variable resources in time and space, constitute the selective agents that act on the phenotypic and genotypic variation of populations in a single generation, could result in evolutionary adaptations, which are simply those traits that are most likely to confer survival and reproduction (evolutionary fitness) of the phenotypes that carry them in successive generations. The bases of adaptation are mainly genetic and transmitted vertically (classical Mendelian mechanisms) or horizontally (in the case of microorganisms). The phenotypic variance of the population is a conjoint consequence of the additive genotypic variance (heritability), nonadditive variance (dominance and epistasis), pleiotropy and the interaction between genotype and environment. The ability of the same genotype to respond to spatial environmental variations can result in phenotypic plasticity that manifests itself through reaction norms. The total phenotypic variation and its genetic and environmental components influence the ability of a population to evolve (evolvability).

scholarly journals The Price equation and reproductive value

2020 ◽  
Vol 375 (1797) ◽  
pp. 20190356 ◽  
Author(s):  
Alan Grafen
Keyword(s):  
Natural Selection ◽  
Fundamental Theorem ◽  
Structured Populations ◽  
Reproductive Value ◽  
Price Equation ◽  
Class Structure ◽  
Theme Issue ◽  
Starting Point ◽  
Important Idea ◽  
Fisher’S Fundamental Theorem

The Price equation is widely recognized as capturing conceptually important properties of natural selection, and is often used to derive versions of Fisher’s fundamental theorem of natural selection, the secondary theorems of natural selection and other significant results. However, class structure is not usually incorporated into these arguments. From the starting point of Fisher’s original connection between fitness and reproductive value, a principled way of incorporating reproductive value and structured populations into the Price equation is explained, with its implications for precise meanings of (two distinct kinds of) reproductive value and of fitness. Once the Price equation applies to structured populations, then the other equations follow. The fundamental theorem itself has a special place among these equations, not only because it always incorporated class structure (and its method is followed for general class structures), but also because that is the result that justifies the important idea that these equations identify the effect of natural selection. The precise definitions of reproductive value and fitness have striking and unexpected features. However, a theoretical challenge emerges from the articulation of Fisher’s structure: is it possible to retain the ecological properties of fitness as well as its evolutionary out-of-equilibrium properties? This article is part of the theme issue ‘Fifty years of the Price equation’.

scholarly journals Steering eco-evolutionary game dynamics with manifold control

2020 ◽  
Vol 476 (2233) ◽  
pp. 20190643 ◽  
Author(s):  
Xin Wang ◽  
Zhiming Zheng ◽  
Feng Fu
Keyword(s):  
Evolutionary Dynamics ◽  
Replicator Dynamics ◽  
Evolutionary Game ◽  
Feedback Loops ◽  
Mathematical Framework ◽  
Stable Manifolds ◽  
Selection Gradient ◽  
Game Dynamics ◽  
Control Approach ◽  
Attraction Basin

Feedback loops between population dynamics of individuals and their ecological environment are ubiquitously found in nature and have shown profound effects on the resulting eco-evolutionary dynamics. By incorporating linear environmental feedback law into the replicator dynamics of two-player games, recent theoretical studies have shed light on understanding the oscillating dynamics of the social dilemma. However, the detailed effects of more general nonlinear feedback loops in multi-player games, which are more common especially in microbial systems, remain unclear. Here, we focus on ecological public goods games with environmental feedbacks driven by a nonlinear selection gradient. Unlike previous models, multiple segments of stable and unstable equilibrium manifolds can emerge from the population dynamical systems. We find that a larger relative asymmetrical feedback speed for group interactions centred on cooperators not only accelerates the convergence of stable manifolds but also increases the attraction basin of these stable manifolds. Furthermore, our work offers an innovative manifold control approach: by designing appropriate switching control laws, we are able to steer the eco-evolutionary dynamics to any desired population state. Our mathematical framework is an important generalization and complement to coevolutionary game dynamics, and also fills the theoretical gap in guiding the widespread problem of population state control in microbial experiments.

scholarly journals Calculating Evolutionary Dynamics in Structured Populations

2009 ◽  
Vol 5 (12) ◽  
pp. e1000615 ◽  
Author(s):  
Charles G. Nathanson ◽  
Corina E. Tarnita ◽  
Martin A. Nowak
Keyword(s):  
Evolutionary Dynamics ◽  
Structured Populations

scholarly journals Disease spread in age structured populations with maternal age effects

2017 ◽  
Vol 20 (4) ◽  
pp. 445-451 ◽  
Author(s):  
Jessica Clark ◽  
Jennie S. Garbutt ◽  
Luke McNally ◽  
Tom J. Little
Keyword(s):  
Maternal Age ◽  
Age Effects ◽  
Structured Populations ◽  
Disease Spread ◽  
Age Structured

scholarly journals Testing the optimality properties of a dual antibiotic treatment in a two-locus, two-allele model

2014 ◽  
Vol 11 (96) ◽  
pp. 20131035 ◽  
Author(s):  
Rafael Peña-Miller ◽  
Ayari Fuentes-Hernandez ◽  
Carlos Reding ◽  
Ivana Gudelj ◽  
Robert Beardmore
Keyword(s):  
Evolutionary Dynamics ◽  
Control Strategies ◽  
Treatment Strategies ◽  
Heterogeneous Population ◽  
Antimicrobial Drugs ◽  
Population Structures ◽  
Optimality Properties ◽  
Allele Model ◽  
Antibiotic Combination

Mathematically speaking, it is self-evident that the optimal control of complex, dynamical systems with many interacting components cannot be achieved with ‘non-responsive’ control strategies that are constant through time. Although there are notable exceptions, this is usually how we design treatments with antimicrobial drugs when we give the same dose and the same antibiotic combination each day. Here, we use a frequency- and density-dependent pharmacogenetics mathematical model based on a standard, two-locus, two-allele representation of how bacteria resist antibiotics to probe the question of whether optimal antibiotic treatments might, in fact, be constant through time. The model describes the ecological and evolutionary dynamics of different sub-populations of the bacterium Escherichia coli that compete for a single limiting resource in a two-drug environment. We use in vitro evolutionary experiments to calibrate and test the model and show that antibiotic environments can support dynamically changing and heterogeneous population structures. We then demonstrate, theoretically and empirically, that the best treatment strategies should adapt through time and constant strategies are not optimal.

scholarly journals Evolutionary game theory for physical and biological scientists. I. Training and validating population dynamics equations

2014 ◽  
Vol 4 (4) ◽  
pp. 20140037 ◽  
Author(s):  
David Liao ◽  
Thea D. Tlsty
Keyword(s):  
Game Theory ◽  
Population Dynamics ◽  
Evolutionary Game Theory ◽  
Evolutionary Dynamics ◽  
Evolutionary Game ◽  
Treatment Strategies ◽  
Analysis Method ◽  
Analysis Techniques ◽  
Game Theoretic ◽  
And Control

Failure to understand evolutionary dynamics has been hypothesized as limiting our ability to control biological systems. An increasing awareness of similarities between macroscopic ecosystems and cellular tissues has inspired optimism that game theory will provide insights into the progression and control of cancer. To realize this potential, the ability to compare game theoretic models and experimental measurements of population dynamics should be broadly disseminated. In this tutorial, we present an analysis method that can be used to train parameters in game theoretic dynamics equations, used to validate the resulting equations, and used to make predictions to challenge these equations and to design treatment strategies. The data analysis techniques in this tutorial are adapted from the analysis of reaction kinetics using the method of initial rates taught in undergraduate general chemistry courses. Reliance on computer programming is avoided to encourage the adoption of these methods as routine bench activities.

scholarly journals Ecological and evolutionary consequences of viral plasticity

2018 ◽  
Author(s):  
Melinda Choua ◽  
Juan A. Bonachela
Keyword(s):  
Field Experiments ◽  
Evolutionary Dynamics ◽  
Physiological State ◽  
Lytic Phage ◽  
Offspring Number ◽  
Host Growth ◽  
Short And Long Term ◽  
Evolutionary Consequences ◽  
Plastic Responses

AbstractViruses can infect any organism. Because viruses use the host machinery to replicate, their performance depends on the host physiological state. For bacteriophages, this host-viral performance link has been characterized empirically and with intracellular theories. Such theories are too detailed to be included in models that study host-phage interactions in the long term, which hinders our understanding of systems that range from pathogens infecting gut bacteria to marine phage shaping present and future oceans. Here, we combined data and models to study the short- and long-term consequences that host physiology has on bacteriophage performance. We compiled data showing the dependence of lytic-phage traits on host growth rate (viral phenotypic “plasticity”) to deduce simple expressions representing such plasticity. We included these expressions in a standard host-phage model, to understand how viral plasticity can break the expected evolutionary trade-off between infection time and viral offspring number. Furthermore, viral plasticity influences dramatically dynamic scenarios (e.g. sudden nutrient pulses or host starvation). We show that the effect of plasticity on offspring number, not generation time, drives the phage ecological and evolutionary dynamics. Standard models do not account for this plasticity, which handicaps their predictability in realistic environments. Our results highlight the importance of viral plasticity to unravel host-phage interactions, and the need of laboratory and field experiments to characterize viral plastic responses across systems.

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