scholarly journals Range expansion shifts clonal interference patterns in evolving populations

2019 ◽  
Author(s):  
Nikhil Krishnan ◽  
Jacob G. Scott
Keyword(s):  
Infectious Diseases ◽  
Spatial Structure ◽  
Range Expansion ◽  
Drug Response ◽  
Evolutionary Dynamics ◽  
Population Expansion ◽  
Structured Populations ◽  
Population Heterogeneity ◽  
Length Scales ◽  
Spatially Structured Populations

ABSTRACTIncreasingly, predicting and even controlling evolutionary processes is a sought after goal in fields ranging from agriculture, artificial intelligence, astrobiology, oncology, and infectious diseases. However, our ability to predict evolution and plan such interventions in real populations is limited in part by our understanding of how spatial structure modulates evolutionary dynamics. Among current clinical assays applied to predict drug response in infectious diseases, for instance, many do not explicitly consider spatial structure and its influence on phenotypic heterogeneity, despite it being an inextricable characteristic of real populations. As spatially structured populations are subject to increased interference of beneficial mutants compared to their well-mixed counter-parts, among other effects, this population heterogeneity and structure may non-trivially impact drug response. In spatially-structured populations, the extent of this mutant interference is density dependent and thus varies with relative position within a meta-population in a manner modulated by mutant frequency, selection strength, migration speed, and habitat length, among other factors. In this study, we examine beneficial mutant fixation dynamics along the front of an asexual population expanding its range. We observe that multiple distinct evolutionary regimes of beneficial mutant origin-fixation dynamics are maintained at characteristic length scales along the front of the population expansion. Using an agent-based simulation of range expansion with mutation and selection in one dimension, we measure these length scales across a range of population sizes, selection strengths, and mutation rates. Furthermore, using simple scaling arguments to adapt theory from well-mixed populations, we find that the length scale at the tip of the front within which ‘local’ mutant fixation occurs in a successive mode decreases with increasing mutation rate, as well as population size in a manner predicted by our derived analytic expression. Finally, we discuss the relevance of our findings to real cellular populations, arguing that this conserved region of successive mutant fixation dynamics at the wave tip can be exploited by emerging evolutionary control strategies.

scholarly journals Between migration load and evolutionary rescue: dispersal, adaptation and the response of spatially structured populations to environmental change

2014 ◽  
Vol 281 (1778) ◽  
pp. 20132795 ◽  
Author(s):  
Elizabeth C. Bourne ◽  
Greta Bocedi ◽  
Justin M. J. Travis ◽  
Robin J. Pakeman ◽  
Rob W. Brooker ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Structured Populations ◽  
Evolutionary Potential ◽  
Beneficial Effects ◽  
Individual Fitness ◽  
Spatially Structured Populations ◽  
Local Selection ◽  
Evolutionary Response ◽  
Evolutionary Rescue ◽  
Opposing Effects

The evolutionary potential of populations is mainly determined by population size and available genetic variance. However, the adaptability of spatially structured populations may also be affected by dispersal: positively by spreading beneficial mutations across sub-populations, but negatively by moving locally adapted alleles between demes. We develop an individual-based, two-patch, allelic model to investigate the balance between these opposing effects on a population's evolutionary response to rapid climate change. Individual fitness is controlled by two polygenic traits coding for local adaptation either to the environment or to climate. Under conditions of selection that favour the evolution of a generalist phenotype (i.e. weak divergent selection between patches) dispersal has an overall positive effect on the persistence of the population. However, when selection favours locally adapted specialists, the beneficial effects of dispersal outweigh the associated increase in maladaptation for a narrow range of parameter space only (intermediate selection strength and low linkage among loci), where the spread of beneficial climate alleles is not strongly hampered by selection against non-specialists. Given that local selection across heterogeneous and fragmented landscapes is common, the complex effect of dispersal that we describe will play an important role in determining the evolutionary dynamics of many species under rapidly changing climate.

scholarly journals Determinants and consequences of dispersal in vertebrates with complex life cycles: a review of pond-breeding amphibians

2018 ◽  
Author(s):  
Hugo Cayuela ◽  
Andrés Valenzuela-Sanchez ◽  
Loïc Teulier ◽  
Íñigo Martínez-Solano ◽  
Jean-Paul Léna ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Current Knowledge ◽  
Life Cycles ◽  
Structured Populations ◽  
Model Systems ◽  
Suitable Model ◽  
Dispersal Patterns ◽  
Central Process ◽  
Complex Life Cycles ◽  
Spatially Structured Populations

Dispersal is a central process in ecology and evolution. It strongly influences the dynamics of spatially structured populations, by affecting population growth rate and local colonization-extinction processes. Dispersal can also influence evolutionary processes because it determines rates and patterns of gene flow in spatially structured populations and is closely linked to local adaptation. For these reasons, dispersal has received considerable attention from ecologists and evolutionary biologists. However, although it has been studied extensively in taxa such as birds and mammals, much less is known about dispersal in vertebrates with complex life cycles such as pond-breeding amphibians. Over the past two decades, researchers have taken an interest in amphibian dispersal and initiated both fundamental and applied studies, using a broad range of experimental and observational approaches. This body of research reveals complex dispersal patterns, causations and syndromes, with dramatic consequences for the demography and genetics of amphibian populations. In this review, our goals are to (1) redefine and clarify the concept of amphibian dispersal, (2) review current knowledge about the effects of individual (i.e., condition-dependent dispersal) and environmental (i.e., context-dependent dispersal) factors during the three stages of dispersal (i.e., emigration, immigration, transience), (3) identify the demographic and genetic consequences of dispersal in spatially structured amphibian populations, and (4) propose new research avenues to extend our understanding of amphibian dispersal. In particular, we emphasize the need to (1) quantify dispersal rate and distance rigorously using suitable model systems, (2) investigate the genetic basis and dispersal evolution patterns, and (3) examine dispersal-related eco-evolutionary dynamics. These proposed research avenues tap from the recent advances in quantitative and molecular methods and have the potential to improve our understanding of dispersal in organisms with complex life cycles.

scholarly journals Antagonism between killer yeast strains as an experimental model for biological nucleation dynamics

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Andrea Giometto ◽  
David R Nelson ◽  
Andrew W Murray
Keyword(s):  
Critical Frequency ◽  
Evolutionary Dynamics ◽  
Structured Populations ◽  
Biological Interactions ◽  
Laboratory Studies ◽  
Microbial Antagonism ◽  
Microbial World ◽  
Experimental Dynamics ◽  
Spatially Structured Populations ◽  
Yeast Strains

Antagonistic interactions are widespread in the microbial world and affect microbial evolutionary dynamics. Natural microbial communities often display spatial structure, which affects biological interactions, but much of what we know about microbial warfare comes from laboratory studies of well-mixed communities. To overcome this limitation, we manipulated two killer strains of the budding yeast Saccharomyces cerevisiae, expressing different toxins, to independently control the rate at which they released their toxins. We developed mathematical models that predict the experimental dynamics of competition between toxin-producing strains in both well-mixed and spatially structured populations. In both situations, we experimentally verified theory's prediction that a stronger antagonist can invade a weaker one only if the initial invading population exceeds a critical frequency or size. Finally, we found that toxin-resistant cells and weaker killers arose in spatially structured competitions between toxin-producing strains, suggesting that adaptive evolution can affect the outcome of microbial antagonism in spatial settings.

scholarly journals Determinants and consequences of dispersal in vertebrates with complex life cycles: a review of pond-breeding amphibians

2018 ◽  
Author(s):  
Hugo Cayuela ◽  
Andrés Valenzuela-Sanchez ◽  
Loïc Teulier ◽  
Íñigo Martínez-Solano ◽  
Jean-Paul Léna ◽  
...  
Keyword(s):  
Evolutionary Dynamics ◽  
Current Knowledge ◽  
Life Cycles ◽  
Structured Populations ◽  
Model Systems ◽  
Suitable Model ◽  
Dispersal Patterns ◽  
Central Process ◽  
Complex Life Cycles ◽  
Spatially Structured Populations

Dispersal is a central process in ecology and evolution. It strongly influences the dynamics of spatially structured populations, by affecting population growth rate and local colonization-extinction processes. Dispersal can also influence evolutionary processes because it determines rates and patterns of gene flow in spatially structured populations and is closely linked to local adaptation. For these reasons, dispersal has received considerable attention from ecologists and evolutionary biologists. However, although it has been studied extensively in taxa such as birds and mammals, much less is known about dispersal in vertebrates with complex life cycles such as pond-breeding amphibians. Over the past two decades, researchers have taken an interest in amphibian dispersal and initiated both fundamental and applied studies, using a broad range of experimental and observational approaches. This body of research reveals complex dispersal patterns, causations and syndromes, with dramatic consequences for the demography and genetics of amphibian populations. In this review, our goals are to (1) redefine and clarify the concept of amphibian dispersal, (2) review current knowledge about the effects of individual (i.e., condition-dependent dispersal) and environmental (i.e., context-dependent dispersal) factors during the three stages of dispersal (i.e., emigration, immigration, transience), (3) identify the demographic and genetic consequences of dispersal in spatially structured amphibian populations, and (4) propose new research avenues to extend our understanding of amphibian dispersal. In particular, we emphasize the need to (1) quantify dispersal rate and distance rigorously using suitable model systems, (2) investigate the genetic basis and dispersal evolution patterns, and (3) examine dispersal-related eco-evolutionary dynamics. These proposed research avenues tap from the recent advances in quantitative and molecular methods and have the potential to improve our understanding of dispersal in organisms with complex life cycles.

scholarly journals Antisocial rewarding in structured populations

2016 ◽  
Author(s):  
Miguel dos Santos ◽  
Jorge Peña
Keyword(s):  
Spatial Structure ◽  
Social Interactions ◽  
Structured Populations ◽  
Theoretic Model ◽  
Mixed Strategies ◽  
Weak Selection ◽  
The Public ◽  
Spatially Structured Populations ◽  
Game Theoretic ◽  
Game Theoretic Model

ABSTRACTCooperation in collective action dilemmas usually breaks down in the absence of additional incentive mechanisms. This tragedy can be escaped if cooperators have the possibility to invest in reward funds that are shared exclusively among cooperators(prosocial rewarding). Yet, the presence of defectors who do not contribute to the public good but do reward themselves(antisocial rewarding) deters cooperation in the absence of additional countermeasures. A recent simulation study suggests that spatial structure is sufficient to prevent antisocial rewarding from deterring cooperation. Here we reinvestigate this issue assuming mixed strategies and weak selection on a game-theoretic model of social interactions, which we also validate using individual-based simulations. We show that increasing reward funds facilitates the maintenance of prosocial rewarding but prevents its evolution from rare, and that spatial structure can sometimes select against the evolution of prosocial rewarding. Our results suggest that, even in spatially structured populations, additional mechanisms are required to prevent antisocial rewarding from deterring cooperation in public goods dilemmas.

More Examples: Adaptive Diversification in Dispersal Rates, the Evolution of Anisogamy, and the Evolution of Trophic Preference

2011 ◽  
Author(s):  
Michael Doebeli
Keyword(s):  
Evolutionary Dynamics ◽  
Fundamental Question ◽  
Structured Populations ◽  
Trophic Levels ◽  
Adaptive Diversification ◽  
The Third ◽  
Spatially Structured Populations ◽  
Evolution Of Complexity ◽  
Gamete Size

This chapter explores three more examples that all arise in the context of fundamental ecological and evolutionary questions to further illustrate the diversifying force of frequency-dependent interactions. The first example concerns the dynamics of spatially structured populations and serves as an excellent case study for illustrating the feedback between ecological and evolutionary dynamics. The second example concerns the evolution of asymmetry in gamete size between the sexes, which sets the stage for the “paradox of sex.” Finally, the third example concerns the fundamental question of the evolution of trophic levels in food webs, that is, the evolution of complexity in ecosystems.

EDITORIAL — CULTURAL EVOLUTION IN SPATIALLY STRUCTURED POPULATIONS: A REVIEW OF ALTERNATIVE MODELING FRAMEWORKS

2012 ◽  
Vol 15 (01n02) ◽  
pp. 1203001 ◽  
Author(s):  
ANNE KANDLER ◽  
CHARLES PERREAULT ◽  
JAMES STEELE
Keyword(s):  
Cultural Evolution ◽  
Evolutionary Dynamics ◽  
Diffusion Theory ◽  
Population Level ◽  
Structured Populations ◽  
Macro Level ◽  
Agent Based ◽  
Spatially Structured Populations ◽  
Cultural Evolutionary ◽  
Spatially Explicit Modeling

We consider the dynamics of cultural evolution in spatially-structured populations. Most spatially explicit modeling approaches can be broadly divided into two classes: micro- and macro-level models. Macro-level models study cultural evolution at the population level and describe the average behavior of the considered system. Conversely, micro-level models focus on the constituent units of the system, and study the evolutionary dynamics that emerge out of the interaction between these units. In this paper, we give an overview of the general properties of micro- and macro-level models using the examples of agent-based simulations and of continuum models based in diffusion theory; we highlight how both frameworks account for spatially-dependent processes. We argue that both micro- and macro-level models are well-suited to describe the process of cultural evolution in spatial settings and stress that micro- and macro-level models should not be considered as competing alternatives, but rather as complementary tools that can provide different insights into cultural evolutionary dynamics. Although adding spatial components to any model increases its complexity, we argue (based on the findings presented by contributors to this Special Issue of Advances in Complex Systems), that the incorporation of space into the evolutionary framework is a necessary step towards a more complete understanding of the process of cultural evolution.

scholarly journals Vector dynamics influence spatially imperfect genetic interventions against disease

2020 ◽  
Author(s):  
Mete K Yuksel ◽  
Christopher H Remien ◽  
Bandita Karki ◽  
James J Bull ◽  
Stephen M Krone
Keyword(s):  
Spatial Structure ◽  
Mathematical Models ◽  
Human Movement ◽  
Structured Populations ◽  
Vector Borne Diseases ◽  
Spatially Structured Populations ◽  
Parasite Reproduction ◽  
Vector Borne ◽  
Genetic Interventions ◽  
Imperfect Coverage

Abstract Background and objectives Genetic engineering and similar technologies offer promising new approaches to controlling human diseases by blocking transmission from vectors. However, in spatially structured populations, imperfect coverage of the vector will leave pockets in which the parasite may persist. Movement by humans may disrupt this local persistence and facilitate eradication when these pockets are small, spreading parasite reproduction outside unprotected areas and into areas that block its reproduction. Here we consider the sensitivity of this process to biological details: do simple generalities emerge that may facilitate interventions? Methodology We develop formal mathematical models of this process similar to standard Ross-Macdonald models, but (i) specifying spatial structure of two patches, with vector transmission blocked in one patch but not in the other, (ii) allowing temporary human movement (travel instead of migration), and (iii) considering two different modes of mosquito biting. Results We find that there is no invariant effect of disrupting spatial structure with travel. For both biting models, travel out of the unprotected patch has different consequences than travel by visitors into the patch, but the effects are reversed between the two biting models. Conclusions and implications Overall, the effect of human travel on the maintenance of vector-borne diseases in structured habitats must be considered in light of the actual biology of mosquito abundances, biting dynamics, and human movement patterns. Lay summary Genetic interventions against pathogens transmitted by insect vectors are promising methods of controlling infectious diseases. These interventions may be imperfect, leaving pockets where the parasite persists. How will human movement between protected and unprotected areas affect persistence? Mathematical models developed here show that the answer is ecology-dependent, depending on vector biting behavior.

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