Bayesian inference of natural selection from spatio-temporal phenotypic data.
This article develops a method for inferring how selection varies between locations and between generations from phenotypic data. It is assumed that generations are non-overlapping and that individuals reproduce by selfing or asexually. A quantitative genetics model taking account of the effects of stabilising natural selection, the environment and mutation on phenotypic means and variances is developed. Explicit results on the evolution of populations are derived and used to develop a Bayesian inference method. The latter is applied to simulated data and to data from a wheat participatory plant breeding program. It has so...
Source: Theoretical Population Biology - December 5, 2019 Category: Biology Authors: David O, van Frank G, Goldringer I, Rivière P, Delof MT Tags: Theor Popul Biol Source Type: research

Fast likelihood calculation for multivariate Gaussian phylogenetic models with shifts.
Abstract Phylogenetic comparative methods (PCMs) have been used to study the evolution of quantitative traits in various groups of organisms, ranging from micro-organisms to animal and plant species. A common approach has been to assume a Gaussian phylogenetic model for the trait evolution along the tree, such as a branching Brownian motion (BM) or an Ornstein-Uhlenbeck (OU) process. Then, the parameters of the process have been inferred based on a given tree and trait data for the sampled species. At the heart of this inference lie multiple calculations of the model likelihood, that is, the probability density of...
Source: Theoretical Population Biology - December 2, 2019 Category: Biology Authors: Mitov V, Bartoszek K, Asimomitis G, Stadler T Tags: Theor Popul Biol Source Type: research

Local fluctuations of genetic processes defined on two time scales, with applications to effective size estimation.
PA Abstract In this paper we develop a general framework for how the genetic composition of a structured population with strong migration between its subunits, evolves over time. The dynamics is described in terms of a vector-valued Markov process of allele, genotype or haplotype frequencies that varies on two time scales. The more rapid changes are random fluctuations in terms of a multivariate autoregressive process, around a quasi equilibrium fix point, whereas the fix point itself varies more slowly according to a diffusion process, along a lower-dimensional subspace. Under mild regularity conditions, the flu...
Source: Theoretical Population Biology - November 25, 2019 Category: Biology Authors: Hössjer O, Tyvand PA Tags: Theor Popul Biol Source Type: research

Dispersal asymmetry in a two-patch system with source-sink populations.
Abstract This paper analyzes source-sink systems with asymmetric dispersal between two patches. Complete analysis on the models demonstrates a mechanism by which the dispersal asymmetry can lead to either an increased total size of the species population in two patches, a decreased total size with persistence in the patches, or even extinction in both patches. For a large growth rate of the species in the source and a fixed dispersal intensity, (i) if the asymmetry is small, the population would persist in both patches and reach a density higher than that without dispersal, in which the population approaches its m...
Source: Theoretical Population Biology - November 25, 2019 Category: Biology Authors: Wu H, Wang Y, Li Y, DeAngelis DL Tags: Theor Popul Biol Source Type: research

Genealogical distances under low levels of selection.
Abstract For a panmictic population of constant size evolving under neutrality, Kingman's coalescent describes the genealogy of a population sample in equilibrium. However, for genealogical trees under selection, not even expectations for most basic quantities like height and length of the resulting random tree are known. Here, we give an analytic expression for the distribution of the total tree length of a sample of size n under low levels of selection in a two-alleles model. We can prove that trees are shorter than under neutrality under genic selection and if the beneficial mutant has dominance h1∕2. The dif...
Source: Theoretical Population Biology - November 21, 2019 Category: Biology Authors: Huss E, Pfaffelhuber P Tags: Theor Popul Biol Source Type: research

Quantifying the forces that maintain prophages in bacterial genomes.
Abstract Genome sequencing has revealed that prophages, viral sequences integrated in a bacterial chromosome, are abundant, accounting for as much as 20% of the bacterial genome. These sequences can confer fitness benefits to the bacterial host, but may also instigate cell death through induction. Several recent investigations have revealed that the distribution of prophage lengths is bimodal, with a clear distinction between small and large prophages. Here we develop a mathematical model of the evolutionary forces affecting the prophage size distribution, and fit this model to three recent data sets. This approac...
Source: Theoretical Population Biology - November 20, 2019 Category: Biology Authors: Khan A, Wahl LM Tags: Theor Popul Biol Source Type: research

Multi-model inference of non-random mating from an information theoretic approach.
uez A Abstract Non-random mating has a significant impact on the evolution of organisms. Here, I developed a modelling framework for discrete traits (with any number of phenotypes) to explore different models connecting the non-random mating causes (mate competition and/or mate choice) and their consequences (sexual selection and/or assortative mating). I derived the formulaefor the maximum likelihood estimates of each model and used information criteria to perform multi-model inference. Simulation results showed a good performance of both model selection and parameter estimation. The methodology was applied to ec...
Source: Theoretical Population Biology - November 19, 2019 Category: Biology Authors: Carvajal-Rodríguez A Tags: Theor Popul Biol Source Type: research

Incorporating tick feeding behaviour into R0 for tick-borne pathogens.
Abstract Tick-borne pathogens pose a considerable disease burden in Europe and North America, where increasing numbers of human cases and the emergence of new tick-borne pathogens has renewed interest in resolving the mechanisms underpinning their geographical distribution and abundance. For Borrelia burgdorferi and tick-borne encephalitis (TBE) virus, transmission of infection from one generation of ticks to another occurs when older nymphal ticks infect younger larval ticks feeding on the same host, either indirectly via systemic infection of the vertebrate host or directly when feeding in close proximity. Here,...
Source: Theoretical Population Biology - November 12, 2019 Category: Biology Authors: Johnstone-Robertson SP, Diuk-Wasser MA, Davis SA Tags: Theor Popul Biol Source Type: research

Competing barnacle species with a time dependent reproduction rate.
Abstract A simple competition model with time varying periodic coefficients, in which two species use different reproduction strategies, is explored in this paper. The two species considered comprise a native species which reproduces once a year over a short time period and an invasive species which is capable of reproducing throughout the entire year. A monotonicity property of the model is instrumental for its analysis. The model reveals that the time difference between the peak of reproduction for the two species is a critical factor in determining the outcome of competition between these species. The impact of...
Source: Theoretical Population Biology - November 12, 2019 Category: Biology Authors: Gallagher MC, Arnold M, Kadaub E, Culloty S, O'Riordan RM, McAllen R, Rachinskii D Tags: Theor Popul Biol Source Type: research

Holt (1977) and apparent competition.
PMID: 31711965 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - November 8, 2019 Category: Biology Authors: Schreiber SJ, Křivan V Tags: Theor Popul Biol Source Type: research

The popularity spectrum applied to a cross-cultural question.
Abstract We investigate a new approach for identifying the contribution of horizontal transmission between groups to cross-cultural similarity. This method can be applied to datasets that record the presence or absence of artefacts, or attributes thereof, in archaeological and ethnographic assemblages, from which popularity spectra can be constructed. Based on analytical and simulation models, we show that the form of such spectra is sensitive to horizontal transmission between groups. We then fit the analytical model to existing datasets by Bayesian MCMC and obtain evidence for strong horizontal transmission in o...
Source: Theoretical Population Biology - October 28, 2019 Category: Biology Authors: Nakamura M, Wakano JY, Aoki K, Kobayashi Y Tags: Theor Popul Biol Source Type: research

Is there a Trivers-Willard effect for parental investment? Modelling evolutionarily stable strategies using a matrix population model with nonlinear mating.
Abstract The Trivers-Willard hypothesis (TWH) states that parents in good condition preferentially produce the sex with a higher variation in reproductive success, whereas parents in bad condition favour the opposite sex. Theorists distinguish two variants of the TWH: (a) a biased sex-ratio at birth and (b) biased parental investment after birth. It has been argued before that the conditions stated by Trivers and Willard (good condition is inherited and affects reproductive success more strongly for one of the sexes) are sufficient for the sex-ratio version but insufficient for the investment version of the TWH. H...
Source: Theoretical Population Biology - October 11, 2019 Category: Biology Authors: Borgstede M Tags: Theor Popul Biol Source Type: research

The importance of Durrett and Levin (1994): "The importance of being discrete (and spatial)".
The importance of Durrett and Levin (1994): "The importance of being discrete (and spatial)". Theor Popul Biol. 2019 Oct 09;: Authors: Pacala SW PMID: 31605704 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - October 9, 2019 Category: Biology Authors: Pacala SW Tags: Theor Popul Biol Source Type: research

Germination variation facilitates the evolution of seed dormancy when coupled with seedling competition.
Abstract Fluctuating environmental conditions have consequences for the evolution of life histories because they cause fitness variance. This variance can favor risk-spreading strategies, often known as bet-hedging strategies, in which growth or reproduction is spread over time or space, with some costs, but greater certainty of success. An important example is seed dormancy in annual plants, in which some fraction of seed remains dormant at any given germination opportunity with the potential of germinating later when environmental conditions may differ. Previous theory shows that environmental variation is criti...
Source: Theoretical Population Biology - October 9, 2019 Category: Biology Authors: Kortessis N, Chesson P Tags: Theor Popul Biol Source Type: research

Adaptive walks on high-dimensional fitness landscapes and seascapes with distance-dependent statistics.
Abstract The dynamics of evolution is intimately shaped by epistasis - interactions between genetic elements which cause the fitness-effect of combinations of mutations to be non-additive. Analyzing evolutionary dynamics that involves large numbers of epistatic mutations is intrinsically difficult. A crucial feature is that the fitness landscape in the vicinity of the current genome depends on the evolutionary history. A key step is thus developing models that enable study of the effects of past evolution on future evolution. In this work, we introduce a broad class of high-dimensional random fitness landscapes fo...
Source: Theoretical Population Biology - October 9, 2019 Category: Biology Authors: Agarwala A, Fisher DS Tags: Theor Popul Biol Source Type: research

The evolution of coexistence theory.
PMID: 31604071 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - October 8, 2019 Category: Biology Authors: Amarasekare P Tags: Theor Popul Biol Source Type: research

"Any news?" Special issue in honor of Marcus Feldman's 75th birthday.
"Any news?" Special issue in honor of Marcus Feldman's 75th birthday. Theor Popul Biol. 2019 Oct;129:1-3 Authors: Ramachandran S, Otto SP, Uyenoyama M, Van Cleve J PMID: 31585596 [PubMed - in process] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - October 1, 2019 Category: Biology Authors: Ramachandran S, Otto SP, Uyenoyama M, Van Cleve J Tags: Theor Popul Biol Source Type: research

Coalescence in the diffusion limit of a Bienaym é-Galton-Watson branching process.
Coalescence in the diffusion limit of a Bienaymé-Galton-Watson branching process. Theor Popul Biol. 2019 Oct 01;: Authors: Burden CJ, Soewongsono AC Abstract We consider the problem of estimating the elapsed time since the most recent common ancestor of a finite random sample drawn from a population which has evolved through a Bienaymé-Galton-Watson branching process. More specifically, we are interested in the diffusion limit appropriate to a supercritical process in the near-critical limit evolving over a large number of time steps. Our approach differs from earlier analyses in that we...
Source: Theoretical Population Biology - October 1, 2019 Category: Biology Authors: Burden CJ, Soewongsono AC Tags: Theor Popul Biol Source Type: research

Enhancing population stability with combined adaptive limiter control and finding the optimal harvesting-restocking balance.
Abstract Fluctuations in population size may have negative consequences (e.g., an increased risk of extinction or the occurrence of repeated outbreaks), and many management strategies are aimed at avoiding them by either only restocking or only harvesting the population. Two of these strategies are adaptive limiter control (ALC) and adaptive threshold harvesting (ATH). With ALC the population is controlled by only restocking and with ATH by only harvesting. We propose the strategy of combined adaptive limiter control (CALC) as the combination of ALC and ATH and study the potential advantages of CALC over ALC and A...
Source: Theoretical Population Biology - September 30, 2019 Category: Biology Authors: Segura J, Hilker FM, Franco D Tags: Theor Popul Biol Source Type: research

Tuljapurkar and Orzack (1980) and Tuljapurkar (1982a,b): Population dynamics in variable environments.
PMID: 31574279 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - September 28, 2019 Category: Biology Authors: Steiner UK Tags: Theor Popul Biol Source Type: research

A multi-epoch model for the number of species within genera.
ois O Abstract An early question in evolutionary theory asked why frequency distributions of taxonomic group sizes exhibit "hollow curves" so frequently. An answer to this question was provided by G. Udny Yule's seminal contribution introducing a discrete model for those distributions. But Yule observed that the fit of his model to observed distributions was sometimes imperfect, in particular for the class of reptiles. The present study introduces a multi-epoch extension of the discrete Yule model that accounts for unobserved extinction of ancient lineages. The multi-epoch model is described as a P&ograv...
Source: Theoretical Population Biology - September 27, 2019 Category: Biology Authors: François O Tags: Theor Popul Biol Source Type: research

Multilocus population-genetic theory.
r R PMID: 31563526 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - September 26, 2019 Category: Biology Authors: Bürger R Tags: Theor Popul Biol Source Type: research

Ancel (2000) on the Baldwin effect.
PMID: 31562843 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - September 25, 2019 Category: Biology Authors: Plotkin JB Tags: Theor Popul Biol Source Type: research

When do factors promoting genetic diversity also promote population persistence? A demographic perspective on Gillespie's SAS-CFF model.
Abstract Classical stochastic demography predicts that environmental stochasticity reduces population growth rates and, thereby, can increase extinction risk. In contrast, in a 1978 Theoretical Population Biology paper, Gillespie demonstrated with his stochastic additive scale and concave fitness function (SAS-CFF) model that environmental stochasticity can promote genetic diversity. Extending the SAS-CFF to account for demography, I examine the simultaneous effects of environmental stochasticity on genetic diversity and population persistence. Explicit expressions for the per-capita growth rates of rare alleles a...
Source: Theoretical Population Biology - September 3, 2019 Category: Biology Authors: Schreiber SJ Tags: Theor Popul Biol Source Type: research

and Muller's ratchet.
PMID: 31473162 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - August 29, 2019 Category: Biology Authors: Desai MM Tags: Theor Popul Biol Source Type: research

Haigh (1978) and Muller's ratchet.
PMID: 31473182 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - August 29, 2019 Category: Biology Authors: Desai MM Tags: Theor Popul Biol Source Type: research

Eco-epidemiological interactions with predator interference and infection.
Abstract Predator interference is a form of competition between predator individuals over access to their prey. There is broad empirical evidence for interference to exist in different strengths in various types of ecological communities. At the same time, parasites are increasingly recognized to alter food web structure and dynamics. In order to investigate the eco-epidemiological interplay between interference and infection, we develop and analyze mathematical models of a predator-prey system, where the predators are subject to both interference and infectious disease. In the absence of infection, equilibrium pr...
Source: Theoretical Population Biology - August 22, 2019 Category: Biology Authors: Bulai IM, Hilker FM Tags: Theor Popul Biol Source Type: research

Donnelly (1983) and the limits of genetic genealogy.
PMID: 31430435 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - August 17, 2019 Category: Biology Authors: Edge MD, Coop G Tags: Theor Popul Biol Source Type: research

The effect of temporal fluctuations on the evolution of host tolerance to parasitism.
In this study, we use a mathematical model to investigate the evolution of host tolerance in a temporally fluctuating environment. We show that investment in tolerance increases in more variable environments, giving qualitatively different evolutionary behaviours when compared to resistance. Once seasonality is introduced evolutionary branching though tolerance can occur and create diversity within the population, although potentially only temporarily. This branching behaviour arises due to the emergence of a negative feedback with the maximum infected density on a cycle, which is strongest when the infected population is ...
Source: Theoretical Population Biology - August 12, 2019 Category: Biology Authors: Ferris C, Best A Tags: Theor Popul Biol Source Type: research

Corrigendum to "A coalescent dual process for a Wright-Fisher diffusion with recombination and its application to haplotype partitioning" [Theor. Popul. Biol. 112 (2016) 126-138].
Corrigendum to "A coalescent dual process for a Wright-Fisher diffusion with recombination and its application to haplotype partitioning" [Theor. Popul. Biol. 112 (2016) 126-138]. Theor Popul Biol. 2019 Aug 05;: Authors: Griffiths RC, Jenkins PA, Lessard S PMID: 31394054 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - August 5, 2019 Category: Biology Authors: Griffiths RC, Jenkins PA, Lessard S Tags: Theor Popul Biol Source Type: research

Strategies of host resistance to pathogens in spatially structured populations: An agent-based evaluation.
In this study we investigate the evolution of several types of host disease resistance strategies, alone or in combination, in spatially structured populations. We construct a spatially explicit, individual-based stochastic model where hosts and parasites interact with each other in a spatial lattice, and interactions are restricted to a given neighbourhood of varying size. We investigate several host resistance strategies, including constitutive (expressed in all resistant hosts), induced (expressed only upon infection), and combinations thereof. We show that a costly constitutive resistance cannot reach fixation, whereas...
Source: Theoretical Population Biology - August 5, 2019 Category: Biology Authors: Boëte C, Seston M, Legros M Tags: Theor Popul Biol Source Type: research

Selection in two-sex stage-structured populations: Genetics, demography, and polymorphism.
Abstract The outcome of natural selection depends on the demographic processes of birth, death, and development. Here, we derive conditions for protected polymorphism in a population characterized by age- or stage-dependent demography with two sexes. We do so using a novel two-sex matrix population model including basic Mendelian genetics (one locus, two alleles, random mating). Selection may operate on survival, growth, or fertility, any or all of which may differ between the sexes. The model can therefore incorporate genes with arbitrary pleiotropic and sex-specific effects. Conditions for protected polymorphism...
Source: Theoretical Population Biology - August 1, 2019 Category: Biology Authors: de Vries C, Caswell H Tags: Theor Popul Biol Source Type: research

Goodman, Keyfitz & Pullum (1974) and the population frequencies of kinship relationships.
Goodman, Keyfitz & Pullum (1974) and the population frequencies of kinship relationships. Theor Popul Biol. 2019 Jul 23;: Authors: Pavard S, Coste CFD PMID: 31348871 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - July 23, 2019 Category: Biology Authors: Pavard S, Coste CFD Tags: Theor Popul Biol Source Type: research

MacArthur (1970) and mechanistic coexistence theory.
PMID: 31344379 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - July 22, 2019 Category: Biology Authors: Chesson P Tags: Theor Popul Biol Source Type: research

Local sensitivity equations for maximum sustainable yield reference points.
Abstract Quantitative fishery harvest strategies in many countries throughout the world are based on maximum sustainable yield (MSY) reference points (RPs); in particular, the fishing mortality rate that produces MSY (i.e. Fmsy) and the population biomass (Bmsy) that results from fishing at Fmsy. There is often great interest in the sensitivity of MSY RPs to their inputs and underlying assumptions. We perturb (i.e. ω) inputs to generate influence curves which we denote as Fmsy(ω) and Bmsy(ω) as functions of ω. We derive diagnostic equations for the slopes of Fmsy(ω) and Bmsy(ω) ...
Source: Theoretical Population Biology - July 22, 2019 Category: Biology Authors: Zheng N, Wang S, Cadigan N Tags: Theor Popul Biol Source Type: research

The Evolving Moran Genealogy.
Abstract We study the evolution of the population genealogy in the classic neutral Moran Model of finite size n∈N and in discrete time. The stochastic transformations that shape a Moran population can be realized directly on its genealogy and give rise to a process on a state space consisting of n-sized binary increasing trees. We derive a number of properties of this process, and show that they are in agreement with existing results on the infinite-population limit of the Moran Model. Most importantly, this process admits time reversal, which makes it possible to simplify the mechanisms determining state cha...
Source: Theoretical Population Biology - July 19, 2019 Category: Biology Authors: Wirtz J, Wiehe T Tags: Theor Popul Biol Source Type: research

Shigesada et  al. (1986) and population spread in heterogeneous environments.
Shigesada et al. (1986) and population spread in heterogeneous environments. Theor Popul Biol. 2019 Jul 18;: Authors: Lutscher F PMID: 31326343 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - July 18, 2019 Category: Biology Authors: Lutscher F Tags: Theor Popul Biol Source Type: research

Indirect effects in a planktonic disease system.
es CE Abstract Indirect effects, both density- and trait-mediated, have been known to act in tandem with direct effects in the interactions of numerous species. They have been shown to affect populations embedded in competitive and mutualistic networks alike. In this work, we introduce a four-dimensional system of ordinary differential equations and investigate the interplay between direct density-effects and density- and trait-mediated indirect effects that take place in a yeast parasite-zooplankton host-incompetent competitor system embedded in a food web which also includes resources and predators. Among our ma...
Source: Theoretical Population Biology - July 15, 2019 Category: Biology Authors: Rapti Z, Merrill TES, Mueller-Brennan B, Kavouras JH, Cáceres CE Tags: Theor Popul Biol Source Type: research

Uniqueness and multiplicity of clines in an environmental pocket.
Abstract The number of clines (i.e., polymorphic equilibria) maintained by a step-environment in a unidimensional pocket at a single diallelic locus is investigated. The monoecious population is locally panmictic; its density is uniform. Migration and viability selection are both weak; the former is homogeneous and symmetric; the latter is directional and usually specified by a unimodal function f(p) of the gene frequency p. If the ratio of the selection intensity to the migration rate exceeds a critical value, at least one cline exists. The general theorems on equilibrium structure determine it in detail for many...
Source: Theoretical Population Biology - July 12, 2019 Category: Biology Authors: Nagylaki T, Su L, Dupont TF Tags: Theor Popul Biol Source Type: research

Meng and Kubatko (2009): Modeling hybridization with coalescence.
PMID: 31302160 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - July 11, 2019 Category: Biology Authors: Degnan JH Tags: Theor Popul Biol Source Type: research

Asymmetric competition, ontogenetic growth and size inequality drive the difference in productivity between two-strata and one-stratum forest stands.
Abstract Size inequality has been considered a key feature of plant population structure with impacts on ecosystem functions. In forest ecosystems, studies examining the relationship between tree size inequality and stand productivity have produced mixed outcomes. These studies found positive, neutral or negative relationships and discussed how this could be influenced by competition for light between trees (e.g. light interception efficiency), but far less attention has been paid to the role played by tree ontogenetic growth. In this article, we present a simple mathematical model that predicts the basal area gro...
Source: Theoretical Population Biology - July 5, 2019 Category: Biology Authors: Cordonnier T, Smadi C, Kunstler G, Courbaud B Tags: Theor Popul Biol Source Type: research

: A unifying framework for modelling evolutionary trees.
PMID: 31279730 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - July 4, 2019 Category: Biology Authors: Steel M Tags: Theor Popul Biol Source Type: research

: On the cusp of a revolution in foraging theory.
PMID: 31279731 [PubMed - as supplied by publisher] (Source: Theoretical Population Biology)
Source: Theoretical Population Biology - July 4, 2019 Category: Biology Authors: Mangel M Tags: Theor Popul Biol Source Type: research

Stationary distribution of the linkage disequilibrium coefficient r2.
Abstract The linkage disequilibrium coefficient r2 is a measure of statistical dependence of the alleles possessed by an individual at different genetic loci. It is widely used in association studies to search for the locations of disease-causing genes on chromosomes. Most studies to date treat r2 as a fixed property of two loci in a finite population, and investigate the sampling distribution of estimators due to the statistical sampling of individuals from the population. Here, we instead consider the distribution of r2 itself under a process of genetic sampling through the generations. Using a classical two-loc...
Source: Theoretical Population Biology - May 27, 2019 Category: Biology Authors: Zhang W, Liu J, Goodman J, Weir BS, Fewster RM Tags: Theor Popul Biol Source Type: research

Cultural and evolutionary dynamics with best-of-k learning when payoffs are uncertain.
Abstract Social learning not only takes the form of random copying of other individuals, but also involves learners' choice of what to learn or from whom to learn. Best-of-k learning refers to a kind of success-biased social learning strategy in which a learner randomly samples k exemplars from the population and imitates the most "successful" one, or the one gaining the highest payoff. While it is intuitive that best-of-k learning can promote the spread of superior variants and thereby enable cumulative cultural evolution, a previous mathematical analysis has shown that it may sometimes result in malada...
Source: Theoretical Population Biology - May 27, 2019 Category: Biology Authors: Takahashi T, Ihara Y Tags: Theor Popul Biol Source Type: research

FST and the triangle inequality for biallelic markers.
Abstract The population differentiation statistic FST, introduced by Sewall Wright, is often treated as a pairwise distance measure between populations. As was known to Wright, however, FST is not a true metric because allele frequencies exist for which it does not satisfy the triangle inequality. We prove that a stronger result holds: for biallelic markers whose allele frequencies differ across three populations, FSTnever satisfies the triangle inequality. We study the deviation from the triangle inequality as a function of the allele frequencies of three populations, identifying the frequency vector at which the...
Source: Theoretical Population Biology - May 24, 2019 Category: Biology Authors: Arbisser IM, Rosenberg NA Tags: Theor Popul Biol Source Type: research

First-order effect of frequency-dependent selection on fixation probability in an age-structured population with application to a public goods game.
Abstract In this paper, we deduce the first-order effect of frequency-dependent viability and fertility selection on the probability of fixation of a mutant in a large finite haploid population with a fixed age structure by applying a direct small perturbation method to the neutral two-timescale genealogical process. This effect is expressed in terms of fixation-fitness coefficients times ancestry coefficients that are related to the effective population size. In the case of constant selection, the fixation-fitness coefficients are functions of the coefficients of viability and fertility selection weighted by repr...
Source: Theoretical Population Biology - May 23, 2019 Category: Biology Authors: Soares CD, Lessard S Tags: Theor Popul Biol Source Type: research

Cyclic outbreaks of forest insects: A two-dimensional individual-based model.
Abstract An individual-based model is presented which shows that cyclic insects outbreaks in the forest (here presented as a certain type of the dynamics of total numbers of insects in the forest) can be a result of the joint action of four factors: (1) spatial structure of the system - resources, green tree biomass, used by larval insects are distributed in a two-dimensional space, (2) properties of trees - their limited resistance to feeding by insects, and regeneration ability after some time of relaxation, when they cannot sustain a local insect population, (3) insect properties - the most important of which i...
Source: Theoretical Population Biology - May 6, 2019 Category: Biology Authors: Uchmański J Tags: Theor Popul Biol Source Type: research

Fitting Markovian binary trees using global and individual demographic data.
Abstract We consider a class of continuous-time branching processes called Markovian binary trees (MBTs), in which the individuals lifetime and reproduction epochs are modeled using a transient Markovian arrival process (TMAP). We develop methods for estimating the parameters of the TMAP by using either age-specific averages of reproduction and mortality rates, or age-specific individual demographic data. Depending on the degree of detail of the available information, we follow a weighted non-linear regression or a maximum likelihood approach. We discuss several criteria to determine the optimal number of states i...
Source: Theoretical Population Biology - May 3, 2019 Category: Biology Authors: Hautphenne S, Massaro M, Turner K Tags: Theor Popul Biol Source Type: research

The expected time to cross extended fitness plateaus.
Abstract For a population to acquire a complex adaptation requiring multiple individually neutral mutations, it must cross a plateau in the fitness landscape. We consider plateaus involving three mutations, and show that large populations can cross them rapidly via lineages that acquire multiple mutations while remaining at low frequency, much faster than the ∝μ3 rate for simultaneous triple mutations. Plateau-crossing is fastest for very large populations. At intermediate population sizes, recombination can greatly accelerate adaptation by combining independent mutant lineages to form triple-mutants. For ...
Source: Theoretical Population Biology - May 2, 2019 Category: Biology Authors: Ghafari M, Weissman D Tags: Theor Popul Biol Source Type: research