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

Yeast Strains

AbstractAntagonistic 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 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.

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

Proceedings of The Royal Society B Biological Sciences ◽

10.1098/rspb.2013.2795 ◽

2014 ◽

Vol 281 (1778) ◽

pp. 20132795 ◽

Cited By ~ 49

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 ◽

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.

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

10.7287/peerj.preprints.27394v1 ◽

2018 ◽

Cited By ~ 4

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 ◽

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.

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

10.7287/peerj.preprints.27394 ◽

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 ◽

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.

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

Adaptive Diversification (MPB-48) ◽

10.23943/princeton/9780691128931.003.0007 ◽

2011 ◽

Author(s):

Michael Doebeli

Keyword(s):

Evolutionary Dynamics ◽

Fundamental Question ◽

Structured Populations ◽

Trophic Levels ◽

Adaptive Diversification ◽

The Third ◽

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

Advances in Complex Systems ◽

10.1142/s0219525912030014 ◽

2012 ◽

Vol 15 (01n02) ◽

pp. 1203001 ◽

Cited By ~ 8

Author(s):

ANNE KANDLER ◽

CHARLES PERREAULT ◽

JAMES STEELE

Keyword(s):

Cultural Evolution ◽

Evolutionary Dynamics ◽

Diffusion Theory ◽

Population Level ◽

Structured Populations ◽

Macro Level ◽

Agent Based ◽

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.

Evolutionary dynamics of collective action in spatially structured populations

Journal of Theoretical Biology ◽

10.1016/j.jtbi.2015.06.039 ◽

2015 ◽

Vol 382 ◽

pp. 122-136 ◽

Cited By ~ 41

Author(s):

Jorge Peña ◽

Georg Nöldeke ◽

Laurent Lehmann

Keyword(s):

Collective Action ◽

Evolutionary Dynamics ◽

Structured Populations ◽

Range expansion shifts clonal interference patterns in evolving populations

10.1101/794867 ◽

2019 ◽

Cited By ~ 2

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 ◽

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.

The influence of fluctuating population densities on evolutionary dynamics

10.1101/444273 ◽

2018 ◽

Author(s):

Hanja Pisa ◽

Joachim Hermisson ◽

Jitka Polechova

Keyword(s):

Ecological Niche ◽

Evolutionary Dynamics ◽

Structured Populations ◽

Population Densities ◽

Ecological Literature ◽

Trade Offs ◽

Population Sizes ◽

And Migration ◽

Maintenance Of Diversity

AbstractThe causes and consequences of fluctuating population densities are an important topic in ecological literature. Yet, the effects of such fluctuations on maintenance of variation in spatially structured populations have received little analytic treatment. We analyze what happens when two habitats coupled by migration not only differ in their trade-offs in selection but also in their demographic stability – and show that equilibrium allele frequencies can change significantly due to ecological feedback arising from locally fluctuating population sizes. When an ecological niche exhibits such fluctuations, these drive an asymmetry in the relative impact of gene flow, and therefore, the equilibrium frequency of the locally adapted type decreases. Our results extend the classic conditions on maintenance of diversity under selection and migration by including the effect of fluctuating population densities. We find simple analytic conditions in terms of the strength of selection, immigration, and the extent of fluctuations between generations in a continent-island model. Whereas weak fluctuations hardly affect coexistence, strong recurrent fluctuations lead to extinction of the type better adapted to the fluctuating niche – even if the invader is locally maladapted. There is a disadvantage to specialization to an unstable habitat, as it makes the population vulnerable to swamping from more stable habitats.

Evolutionary dynamics of collective action in spatially structured populations

10.1101/012229 ◽

2014 ◽

Cited By ~ 1

Author(s):

Jorge Peña ◽

Georg Nöldeke ◽

Laurent Lehmann

Keyword(s):

Collective Action ◽

Social Evolution ◽

Economies Of Scale ◽

Evolutionary Dynamics ◽

Empirical Studies ◽

Structured Populations ◽

Collective Good ◽

Mathematical Framework ◽

Discrete Action

Many models proposed to study the evolution of collective action rely on a formalism that represents social interactions asn-player games between individuals adopting discrete actions such as cooperate and defect. Despite the importance of spatial structure in biological collective action, the analysis ofn-player games games in spatially structured populations has so far proved elusive. We address this problem by considering mixed strategies and by integrating discrete-actionn-player games into the direct fitness approach of social evolution theory. This allows to conveniently identify convergence stable strategies and to capture the effect of population structure by a single structure coefficient, namely, the pairwise (scaled) relatedness among interacting individuals. As an application, we use our mathematical framework to investigate collective action problems associated with the provision of three different kinds of collective goods, paradigmatic of a vast array of helping traits in nature: “public goods” (both providers and shirkers can use the good, e.g., alarm calls), “club goods” (only providers can use the good, e.g., participation in collective hunting), and “charity goods” (only shirkers can use the good, e.g., altruistic sacrifice). We show that relatedness promotes the evolution of collective action in different ways depending on the kind of collective good and its economies of scale. Our findings highlight the importance of explicitly accounting for relatedness, the kind of collective good, and the economies of scale in theoretical and empirical studies of the evolution of collective action.