Evolutionary suicide through a non-catastrophic bifurcation: adaptive dynamics of pathogens with frequency-dependent transmission

During bouts of evolutionary diversification, such as adaptive radiations, the emerging species cluster around different locations in phenotype space. How such multimodal patterns in phenotype space can emerge from a single ancestral species is a fundamental question in biology. Frequency-dependent competition is one potential mechanism for such pattern formation, as has previously been shown in models based on the theory of adaptive dynamics. Here, we demonstrate that also in models similar to those used in quantitative genetics, phenotype distributions can split into multiple modes under the force of frequency-dependent competition. In sexual populations, this requires assortative mating, and we show that the multimodal splitting of initially unimodal distributions occurs over a range of assortment parameters. In addition, assortative mating can be favoured evolutionarily even if it incurs costs, because it provides a means of alleviating the effects of frequency dependence. Our results reveal that models at both ends of the spectrum between essentially monomorphic (adaptive dynamics) and fully polymorphic (quantitative genetics) yield similar results. This underscores that frequency-dependent selection is a strong agent of pattern formation in phenotype distributions, potentially resulting in adaptive speciation.

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On Λ-Fleming–Viot processes with general frequency-dependent selection

Journal of Applied Probability ◽

10.1017/jpr.2020.55 ◽

2020 ◽

Vol 57 (4) ◽

pp. 1162-1197

Author(s):

Adrian Gonzalez Casanova ◽

Charline Smadi

Keyword(s):

Population Genetics ◽

Adaptive Dynamics ◽

Large Population ◽

Biological Evolution ◽

Strong Solutions ◽

Biological Interactions ◽

Diffusion Term ◽

Frequency Dependent ◽

Frequency Dependent Selection ◽

General Frequency

AbstractWe construct a multitype constant-size population model allowing for general selective interactions as well as extreme reproductive events. Our multidimensional model aims for the generality of adaptive dynamics and the tractability of population genetics. It generalises the idea of Krone and Neuhauser [39] and González Casanova and Spanò [29], who represented the selection by allowing individuals to sample several potential parents in the previous generation before choosing the ‘strongest’ one, by allowing individuals to use any rule to choose their parent. The type of the newborn can even not be one of the types of the potential parents, which allows modelling mutations. Via a large population limit, we obtain a generalisation of $\Lambda$ -Fleming–Viot processes, with a diffusion term and a general frequency-dependent selection, which allows for non-transitive interactions between the different types present in the population. We provide some properties of these processes related to extinction and fixation events, and give conditions for them to be realised as unique strong solutions of multidimensional stochastic differential equations with jumps. Finally, we illustrate the generality of our model with applications to some classical biological interactions. This framework provides a natural bridge between two of the most prominent modelling frameworks of biological evolution: population genetics and eco-evolutionary models.

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Adaptive Diversification (MPB-48)

10.23943/princeton/9780691128931.001.0001 ◽

2011 ◽

Cited By ~ 17

Author(s):

Michael Doebeli

Keyword(s):

Evolutionary Biology ◽

Biological Diversity ◽

Adaptive Dynamics ◽

Theoretical Treatment ◽

Mathematical Framework ◽

Evolutionary Branching ◽

Rare Type ◽

Frequency Dependent ◽

Frequency Dependent Selection ◽

Adaptive Diversification

Understanding the mechanisms driving biological diversity remains a central problem in ecology and evolutionary biology. Traditional explanations assume that differences in selection pressures lead to different adaptations in geographically separated locations. This book takes a different approach and explores adaptive diversification—diversification rooted in ecological interactions and frequency-dependent selection. In any ecosystem, birth and death rates of individuals are affected by interactions with other individuals. What is an advantageous phenotype therefore depends on the phenotype of other individuals, and it may often be best to be ecologically different from the majority phenotype. Such rare-type advantage is a hallmark of frequency-dependent selection and opens the scope for processes of diversification that require ecological contact rather than geographical isolation. This book investigates adaptive diversification using the mathematical framework of adaptive dynamics. Evolutionary branching is a paradigmatic feature of adaptive dynamics that serves as a basic metaphor for adaptive diversification, and the book explores the scope of evolutionary branching in many different ecological scenarios, including models of coevolution, cooperation, and cultural evolution. It also uses alternative modeling approaches. Stochastic, individual-based models are particularly useful for studying adaptive speciation in sexual populations, and partial differential equation models confirm the pervasiveness of adaptive diversification. Showing that frequency-dependent interactions are an important driver of biological diversity, the book provides a comprehensive theoretical treatment of adaptive diversification.

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Adaptive Dynamics of Altruistic Cooperation in a Metapopulation: Evolutionary Emergence of Cooperators and Defectors or Evolutionary Suicide?

Bulletin of Mathematical Biology ◽

10.1007/s11538-011-9638-4 ◽

2011 ◽

Vol 73 (11) ◽

pp. 2605-2626 ◽

Cited By ~ 14

Author(s):

Kalle Parvinen

Keyword(s):

Adaptive Dynamics ◽

Evolutionary Suicide ◽

Evolutionary Emergence

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Eco-evolutionary feedbacks, adaptive dynamics and evolutionary rescue theory

Philosophical Transactions of the Royal Society B Biological Sciences ◽

10.1098/rstb.2012.0081 ◽

2013 ◽

Vol 368 (1610) ◽

pp. 20120081 ◽

Cited By ~ 60

Author(s):

Regis Ferriere ◽

Stéphane Legendre

Keyword(s):

Extinction Risk ◽

Adaptive Dynamics ◽

Population Viability ◽

Small Population ◽

Adaptive Process ◽

Evolutionary Rescue ◽

The Face ◽

Population Sizes ◽

Evolutionary Suicide ◽

Dynamics Models

Adaptive dynamics theory has been devised to account for feedbacks between ecological and evolutionary processes. Doing so opens new dimensions to and raises new challenges about evolutionary rescue. Adaptive dynamics theory predicts that successive trait substitutions driven by eco-evolutionary feedbacks can gradually erode population size or growth rate, thus potentially raising the extinction risk. Even a single trait substitution can suffice to degrade population viability drastically at once and cause ‘evolutionary suicide’. In a changing environment, a population may track a viable evolutionary attractor that leads to evolutionary suicide, a phenomenon called ‘evolutionary trapping’. Evolutionary trapping and suicide are commonly observed in adaptive dynamics models in which the smooth variation of traits causes catastrophic changes in ecological state. In the face of trapping and suicide, evolutionary rescue requires that the population overcome evolutionary threats generated by the adaptive process itself. Evolutionary repellors play an important role in determining how variation in environmental conditions correlates with the occurrence of evolutionary trapping and suicide, and what evolutionary pathways rescue may follow. In contrast with standard predictions of evolutionary rescue theory, low genetic variation may attenuate the threat of evolutionary suicide and small population sizes may facilitate escape from evolutionary traps.

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