scholarly journals An inclusive fitness analysis of synergistic interactions in structured populations

2012 ◽  
Vol 279 (1747) ◽  
pp. 4596-4603 ◽  
Author(s):  
Peter Taylor ◽  
Wes Maciejewski
Keyword(s):  
Frequency Dependence ◽  
Allele Frequency ◽  
Inclusive Fitness ◽  
Selective Advantage ◽  
Structured Populations ◽  
Weak Selection ◽  
Synergistic Interactions ◽  
Fitness Effects ◽  
Structured Population

We study the evolution of a pair of competing behavioural alleles in a structured population when there are non-additive or ‘synergistic’ fitness effects. Under a form of weak selection and with a simple symmetry condition between a pair of competing alleles, Tarnita et al. provide a surprisingly simple condition for one allele to dominate the other. Their condition can be obtained from an analysis of a corresponding simpler model in which fitness effects are additive. Their result uses an average measure of selective advantage where the average is taken over the long-term—that is, over all possible allele frequencies—and this precludes consideration of any frequency dependence the allelic fitness might exhibit. However, in a considerable body of work with non-additive fitness effects—for example, hawk–dove and prisoner's dilemma games—frequency dependence plays an essential role in the establishment of conditions for a stable allele-frequency equilibrium. Here, we present a frequency-dependent generalization of their result that provides an expression for allelic fitness at any given allele frequency p . We use an inclusive fitness approach and provide two examples for an infinite structured population. We illustrate our results with an analysis of the hawk–dove game.

What Is Fitness?

2015 ◽  
Author(s):  
James A.R. Marshall
Keyword(s):  
Reproductive Success ◽  
Inclusive Fitness ◽  
Structured Populations ◽  
Reproductive Value ◽  
Costs And Benefits ◽  
Risk Of Death ◽  
Fitness Effects ◽  
Inclusive Fitness Theory ◽  
Definition Of ◽  
Evolutionary Fitness

This chapter considers the problem of correctly defining fitness costs and benefits in inclusive fitness theory, when competition occurs between offspring who are relatives. It reviews the definition of evolutionary fitness and shows how its misinterpretation explains many previous misunderstandings as to whether inclusive fitness theory always makes accurate predictions. The chapter begins with a discussion of Haldane's dilemma, which can be formalized with fitness equations that show that the risk of death can make fitness effects all-or-nothing. It then examines how inclusive fitness models can be constructed to deal with reproductive value and class-structured populations. It also shows how costs and benefits can be expressed as payoffs that are proportional to reproductive success, as changes in production of offspring, or as changes in evolutionary fitness. Finally, it presents examples that illustrate when fitness, payoffs, and fecundity are different, and how inclusive fitness analyses can be performed properly in such situations.

scholarly journals Evolutionary dynamics of n -player games played by relatives

2014 ◽  
Vol 369 (1642) ◽  
pp. 20130359 ◽  
Author(s):  
Hisashi Ohtsuki
Keyword(s):  
Social Interactions ◽  
Genetic Association ◽  
Kin Selection ◽  
Social Evolution ◽  
Evolutionary Dynamics ◽  
Inclusive Fitness ◽  
Theoretical Frameworks ◽  
Fitness Effects ◽  
Structured Population ◽  
Core Concepts

One of the core concepts in social evolution theory is kin selection. Kin selection provides a perspective to understand how natural selection operates when genetically similar individuals are likely to interact. A family-structured population is an excellent example of this, where relatives are engaged in social interactions. Consequences of such social interactions are often described in game-theoretical frameworks, but there is a growing consensus that a naive inclusive fitness accounting with dyadic relatedness coefficients are of limited use when non-additive fitness effects are essential in those situations. Here, I provide a general framework to analyse multiplayer interactions among relatives. Two important results follow from my analysis. First, it is generally necessary to know the n -tuple genetic association of family members when n individuals are engaged in social interactions. However, as a second result, I found that, for a special class of games, we need only measures of lower-order genetic association to fully describe its evolutionary dynamics. I introduce the concept of degree of the game and show how this degree is related to the degree of genetic association.

scholarly journals When do individuals maximize their inclusive fitness?

2019 ◽  
Author(s):  
Laurent Lehmann ◽  
François Rousset
Keyword(s):  
Behavioral Ecology ◽  
Mutant Allele ◽  
Inclusive Fitness ◽  
Order Approximation ◽  
Structured Populations ◽  
Weak Selection ◽  
Individual Control ◽  
First Order ◽  
Best Response ◽  
First Order Approximation

AbstractAdaptation is often described in behavioral ecology as individuals maximizing their inclusive fitness. Under what conditions does this hold and how does this relate to the gene-centered perspective of adaptation? We unify and extend the literature on these questions to class-structured populations. We demonstrate that the maximization (in the best-response sense) of class-specific inclusive fitness obtains in uninvadable population states (meaning that all deviating mutant go extinct). This defines a genuine actor-centered perspective on adaptation. But this inclusive fitness is assigned to all bearers of a mutant allele in a given class and depends on distributions of demographic and genetic contexts. These distributions, in turn, usually depend on events in previous generations and are thus not under individual control. This prevents, in general, from envisioning individuals themselves as autonomous fitness-maximizers, each with its own inclusive fitness. For weak selection, however, the dependence on earlier events can be neglected. We then show that each individual in each class appears to maximize its own inclusive fitness when all other individuals exhibit fitness-maximizing behavior. This defines a genuine individual-centered perspective of adaptation and justifies formally, as a first-order approximation, the long-heralded view of individuals appearing to maximize their own inclusive fitness.

scholarly journals Population structure and coalescence in pedigrees: comparisons to the structured coalescent and a framework for inference

2016 ◽  
Author(s):  
Peter R. Wilton ◽  
Pierre Baduel ◽  
Matthieu M. Landon ◽  
John Wakeley
Keyword(s):  
Structured Populations ◽  
Mixture Of Distributions ◽  
Initial Sample ◽  
Migration Rates ◽  
Maximum Likelihood Approach ◽  
Structured Population ◽  
Recent Sample ◽  
Likelihood Approach ◽  
Structured Coalescent

AbstractContrary to what is often assumed in population genetics, independently segregating loci do not have completely independent ancestries, since all loci are inherited through a single, shared population pedigree. Previous work has shown that the non-independence between gene genealogies of independently segregating loci created by the population pedigree is weak in panmictic populations, and predictions made from standard coalescent theory are accurate for populations that are at least moderately sized. Here, we investigate patterns of coalescence in pedigrees of structured populations. We find that the pedigree creates deviations away from the predictions of the structured coalescent that persist on a longer timescale than in the case of panmictic populations. Nevertheless, we find that the structured coalescent provides a reasonable approximation for the coalescent process in structured population pedigrees so long as migration events are moderately frequent and there are no migration events in the recent pedigree of the sample. When there are migration events in the recent sample pedigree, we find that distributions of coalescence in the sample can be modeled as a mixture of distributions from different initial sample configurations. We use this observation to motivate a maximum-likelihood approach for inferring migration rates and mutation rates jointly with features of the pedigree such as recent migrant ancestry and recent relatedness. Using simulation, we show that our inference framework accurately recovers long-term migration rates in the presence of recent migration events in the sample pedigree.

scholarly journals Extraordinary Self-Sacrifice

2017 ◽  
Author(s):  
D.B. Krupp
Keyword(s):  
Inclusive Fitness ◽  
Simple Rule ◽  
Fitness Effects ◽  
Structured Population ◽  
Spatially Structured Population

AbstractTheories of self-sacrifice ordinarily assume that actors will have larger fitness effects on recipients than on themselves. There are, however, conditions in which actors can pay costs that exceed the altruistic benefits they provide or the spiteful costs they impose. In a spatially structured population, I show that such “extraordinary” self-sacrifice evolves when actors use information about kinship and dispersal to maximize inclusive fitness. The result can be described by a simple rule: extraordinary self-sacrifice evolves when the actor’s neighbors are kin and the recipient’s neighbors are not.

scholarly journals Prediction of Genetic Contributions and Generation Intervals in Populations With Overlapping Generations Under Selection

Genetics ◽  
1999 ◽  
Vol 151 (3) ◽  
pp. 1197-1210 ◽  
Author(s):  
Piter Bijma ◽  
John A Woolliams
Keyword(s):  
Gene Flow ◽  
Overlapping Generations ◽  
Selective Advantage ◽  
Turnover Time ◽  
Breeding Value ◽  
Age Classes ◽  
Generation Interval ◽  
Young Parents ◽  
Genetic Contributions

Abstract A method to predict long-term genetic contributions of ancestors to future generations is studied in detail for a population with overlapping generations under mass or sib index selection. An existing method provides insight into the mechanisms determining the flow of genes through selected populations, and takes account of selection by modeling the long-term genetic contribution as a linear regression on breeding value. Total genetic contributions of age classes are modeled using a modified gene flow approach and long-term predictions are obtained assuming equilibrium genetic parameters. Generation interval was defined as the time in which genetic contributions sum to unity, which is equal to the turnover time of genes. Accurate predictions of long-term genetic contributions of individual animals, as well as total contributions of age classes were obtained. Due to selection, offspring of young parents had an above-average breeding value. Long-term genetic contributions of youngest age classes were therefore higher than expected from the age class distribution of parents, and generation interval was shorter than the average age of parents at birth of their offspring. Due to an increased selective advantage of offspring of young parents, generation interval decreased with increasing heritability and selection intensity. The method was compared to conventional gene flow and showed more accurate predictions of long-term genetic contributions.

scholarly journals Evolutionary Stability for Interactions among Kin under Quantitative Inheritance.

Genetics ◽  
1989 ◽  
Vol 121 (4) ◽  
pp. 877-889
Author(s):  
A B Harper
Keyword(s):  
Inclusive Fitness ◽  
Fitness Function ◽  
Quantitative Inheritance ◽  
Evolutionarily Stable Strategies ◽  
Environmental Variance ◽  
Pairwise Interactions ◽  
Simplifying Assumptions ◽  
Multilocus Model ◽  
Evolutionarily Stable

Abstract The theory of evolutionarily stable strategies (ESS) predicts the long-term evolutionary outcome of frequency-dependent selection by making a number of simplifying assumptions about the genetic basis of inheritance. I use a symmetrized multilocus model of quantitative inheritance without mutation to analyze the results of interactions between pairs of related individuals and compare the equilibria to those found by ESS analysis. It is assumed that the fitness changes due to interactions can be approximated by the exponential of a quadratic surface. The major results are the following. (1) The evolutionarily stable phenotypes found by ESS analysis are always equilibria of the model studied here. (2) When relatives interact, one of the two conditions for stability of equilibria differs between the two models; this can be accounted for by positing that the inclusive fitness function for quantitative characters is slightly different from the inclusive fitness function for characters determined by a single locus. (3) The inclusion of environmental variance will in general change the equilibrium phenotype, but the equilibria of ESS analysis are changed to the same extent by environmental variance. (4) A class of genetically polymorphic equilibria occur, which in the present model are always unstable. These results expand the range of conditions under which one can validly predict the evolution of pairwise interactions using ESS analysis.

scholarly journals Selection, Subdivision and Extinction and Recolonization

Genetics ◽  
2004 ◽  
Vol 166 (2) ◽  
pp. 1105-1114 ◽  
Author(s):  
Joshua L Cherry
Keyword(s):  
Frequency Dependence ◽  
Allele Frequency ◽  
Deleterious Alleles ◽  
Subdivided Population ◽  
Theoretical Predictions ◽  
Subdivided Populations ◽  
Fixation Probabilities ◽  
Selection Parameters ◽  
To Come ◽  
Do So

Abstract In a subdivided population, the interaction between natural selection and stochastic change in allele frequency is affected by the occurrence of local extinction and subsequent recolonization. The relative importance of selection can be diminished by this additional source of stochastic change in allele frequency. Results are presented for subdivided populations with extinction and recolonization where there is more than one founding allele after extinction, where these may tend to come from the same source deme, where the number of founding alleles is variable or the founders make unequal contributions, and where there is dominance for fitness or local frequency dependence. The behavior of a selected allele in a subdivided population is in all these situations approximately the same as that of an allele with different selection parameters in an unstructured population with a different size. The magnitude of the quantity Nese, which determines fixation probability in the case of genic selection, is always decreased by extinction and recolonization, so that deleterious alleles are more likely to fix and advantageous alleles less likely to do so. The importance of dominance or frequency dependence is also altered by extinction and recolonization. Computer simulations confirm that the theoretical predictions of both fixation probabilities and mean times to fixation are good approximations.

scholarly journals Accumulation of mutations in sexual and asexual populations

1987 ◽  
Vol 49 (2) ◽  
pp. 135-146 ◽  
Author(s):  
Pekka Pamilo ◽  
Masatoshi Nei ◽  
Wen-Hsiung Li
Keyword(s):  
Weak Selection ◽  
Population Variance ◽  
Asexual Population ◽  
Term Evolution ◽  
A Genome ◽  
Analytical Formulae ◽  
The Mean ◽  
Asexual Populations ◽  
Mutant Genes

SummaryThe accumulation of beneficial and harmful mutations in a genome is studied by using analytical methods as well as computer simulation for different modes of reproduction. The modes of reproduction examined are biparental (bisexual, hermaphroditic), uniparental (selfing, automictic, asexual) and mixed (partial selfing, mixture of hermaphroditism and parthenogenesis). It is shown that the rates of accumulation of both beneficial and harmful mutations with weak selection depend on the within-population variance of the number of mutant genes per genome. Analytical formulae for this variance are derived for neutral mutant genes for hermaphroditic, selfing and asexual populations; the neutral variance is largest in a selfing population and smallest in an asexual population. Directional selection reduces the population variance in most cases, whereas recombination partially restores the reduced variance. Therefore, biparental organisms accumulate beneficial mutations at the highest rate and harmful mutations at the lowest rate. Selfing organisms are intermediate between biparental and asexual organisms. Even a limited amount of outcrossing in largely selfing and parthenogenetic organisms markedly affects the accumulation rates. The accumulation of mutations is likely to affect the mean population fitness only in long-term evolution.

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