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Theoretical Population Biology

Lilian Sofia Sepulveda Salcedo, Michel De Lara
Managing infectious diseases is a world public health issue, plagued by uncertainties. In this paper, we analyze the problem of viable control of a dengue outbreak under uncertainty. For this purpose, we develop a controlled Ross-Macdonald model with mosquito vector control by fumigation, and with uncertainties affecting the dynamics; both controls and uncertainties are supposed to change only once a day, then remain stationary during the day. The robust viability kernel is the set of all initial states such that there exists at least a strategy of insecticide spraying which guarantees that the number of infected individuals remains below a threshold, for all times, and whatever the sequences of uncertainties...
February 16, 2019: Theoretical Population Biology
Danya Rose, Kristen Hawkes, Peter S Kim
The adult sex ratio (ASR) is defined as the number of fertile males divided by the number of fertile females in a population. We build an ODE model with minimal age structure, in which males compete for paternities using either a multiple-mating or searching-then-guarding strategy, to investigate the value of ASR as an index for predicting which strategy males will adopt, with a focus in our investigation on the differences of strategy choice between chimpanzees (Pan troglodytes) and human hunter-gatherers (Homo sapiens)...
February 13, 2019: Theoretical Population Biology
Oana Carja, Nicole Creanza
Cultural processes, as well as the selection pressures experienced by individuals in a population over time and space, are fundamentally stochastic. Phenotypic variability, together with imperfect phenotypic transmission between parents and offspring, has been previously shown to play an important role in evolutionary rescue and (epi)genetic adaptation of populations to fluctuating temporal environmental pressures. This type of evolutionary bet-hedging does not confer a direct benefit to a single individual, but can instead increase the adaptability of the whole lineage...
February 4, 2019: Theoretical Population Biology
Jason Bertram, Joanna Masel
Selection is commonly described by assigning constant relative fitness values to genotypes. Yet population density is often regulated by crowding. Relative fitness may then depend on density, and selection can change density when it acts on a density-regulating trait. When strong density-dependent selection acts on a density-regulating trait, selection is no longer describable by density-independent relative fitnesses, even in demographically stable populations. These conditions are met in most previous models of density-dependent selection (e...
January 18, 2019: Theoretical Population Biology
Francisco Úbeda, Timothy W Russell, Vincent A A Jansen
Recombination in mammals is not uniformly distributed along the chromosome but concentrated in small regions known as recombination hotspots. Recombination starts with the double-strand break of a chromosomal sequence and results in the transmission of the sequence that does not break (preventing recombination) more often than the sequence that breaks (allowing recombination). Thus recombination itself renders individual recombination hotspots inactive and over time should drive them to extinction in the genome...
January 17, 2019: Theoretical Population Biology
Marcy K Uyenoyama, Naoki Takebayashi, Seiji Kumagai
We present a method for inductively determining exact allele frequency spectrum (AFS) probabilities for samples derived from a population comprising two demes under the infinite-allele model of mutation. This method builds on a labeled coalescent argument to extend the Ewens sampling formula (ESF) to structured populations. A key departure from the panmictic case is that the AFS conditioned on the number of alleles in the sample is no longer independent of the scaled mutation rate (θ). In particular, biallelic site frequency spectra, widely-used in explorations of genome-wide patterns of variation, depend on the mutation rate in structured populations...
January 11, 2019: Theoretical Population Biology
Lam Si Tung Ho, Vu Dinh, Cuong V Nguyen
We consider the ancestral state reconstruction problem where we need to infer phenotypes of ancestors using observations from present-day species. For this problem, we propose a multi-task learning method that uses regularized maximum likelihood to estimate the ancestral states of various traits simultaneously. We then show both theoretically and by simulation that this method improves the estimates of the ancestral states compared to the maximum likelihood method. The result also indicates that for the problem of ancestral state reconstruction under the Brownian motion model, the maximum likelihood method can be improved...
January 11, 2019: Theoretical Population Biology
Liudmyla Vasylenko, Marcus W Feldman, Christos Papadimitriou, Adi Livnat
In evolutionary biology, randomness has been perceived as a force that, in and of itself, is capable of inventing: mutation creates new genetic information at random across the genome which leads to phenotypic change, which is then subject to selection. However, in science in general and in computer science in particular, the widespread use of randomness takes a different form. Here, randomization allows for the breaking of pattern, as seen for example in its removal of biases (patterns) in random sampling or random assignment to conditions...
January 9, 2019: Theoretical Population Biology
Lee Altenberg, Nicole Creanza, Laurel Fogarty, Lilach Hadany, Oren Kolodny, Kevin N Laland, Laurent Lehmann, Sarah P Otto, Noah A Rosenberg, Jeremy Van Cleve, John Wakeley
This article consists of commentaries on a selected group of papers of Marc Feldman published in Theoretical Population Biology from 1970 to the present. The papers describe a diverse set of population-genetic models, covering topics such as cultural evolution, social evolution, and the evolution of recombination. The commentaries highlight Marc Feldman's role in providing mathematically rigorous formulations to explore qualitative hypotheses, in many cases generating surprising conclusions.
December 26, 2018: Theoretical Population Biology
Edward W Tekwa, Andrew Gonzalez, Michel Loreau
Natural selection can favour cooperation, but it is unclear when cooperative populations should be larger than less cooperative ones. While experiments have shown that cooperation can increase population size, cooperation and population size can become negatively correlated if spatial processes affect both variables in opposite directions. We use a simple mathematical model of spatial common-pool resource production to investigate how space affects the cooperation-population size relationship. We find that only cooperation that is sufficiently beneficial to neighbours increases population size...
December 21, 2018: Theoretical Population Biology
A Carvajal-Rodríguez
The mating distribution caused by mate choice can be expressed as a gain in information with respect to random mating. In that view, the population phenotype frequencies had been considered constant during the breeding season. Here, such restriction was relaxed to consider encounter-mating processes in which first, the encounter between partners depends on the phenotype distribution of the population, and second, the mating after the encounter depends on the mutual mating propensities. Under this setting, the population phenotype frequencies are no longer constant because the process of pair formation occurs in discrete intervals of time, called mating rounds where at least one mating pair is formed, and the frequency of phenotypes available for the next mating, changes...
December 18, 2018: Theoretical Population Biology
James E Johndrow, Julia A Palacios
Recovery of population size history from molecular sequence data is an important problem in population genetics. Inference commonly relies on a coalescent model linking the population size history to genealogies. The high computational cost of estimating parameters from these models usually compels researchers to select a subset of the available data or to rely on insufficient summary statistics for statistical inference. We consider the problem of recovering the true population size history from two possible alternatives on the basis of coalescent time data previously considered by Kim et al...
December 17, 2018: Theoretical Population Biology
Samuele Soraggi, Carsten Wiuf
We provide a general mathematical framework based on the theory of graphical models to study admixture graphs. Admixture graphs are used to describe the ancestral relationships between past and present populations, allowing for population merges and migration events, by means of gene flow. We give various mathematical properties of admixture graphs with particular focus on properties of the so-called F-statistics. Also the Wright-Fisher model is studied and a general expression for the loss of heterozygosity is derived...
December 15, 2018: Theoretical Population Biology
Ilan Eshel
The dynamics of long-term evolution in a complex genetically-structured population with a flux of random mutations is employed here to study the evolution of mutual altruism between relatives that are encountered repeatedly, where the level of altruism is measured by the risk one is willing to accept in order to save the life of one's relative. It is shown that regardless of the number of loci involved, of the rates of recombination among them, and of the intensity of the selection forces, the long-term dynamics can phenotypically converge only to a level of altruism that maximizes the individual inclusive fitness as it ha previously defined by students of the individual approach to evolution...
December 14, 2018: Theoretical Population Biology
John Wakeley, Martin Nowak
We describe an iterated game between two players, in which the payoff is to survive a number of steps. Expected payoffs are probabilities of survival. A key feature of the game is that individuals have to survive on their own if their partner dies. We consider individuals with hardwired, unconditional behaviors or strategies. When both players are present, each step is a symmetric two-player game. The overall survival of the two individuals forms a Markov chain. As the number of iterations tends to infinity, all probabilities of survival decrease to zero...
December 12, 2018: Theoretical Population Biology
Yuanshi Wang, Donald L DeAngelis
Previous mathematical analyses have shown that, for certain parameter ranges, a population, described by logistic equations on a set of connected patches, and diffusing among them, can reach a higher equilibrium total population when the local carrying capacities are heterogeneously distributed across patches, than when carrying capacities having the same total sum are homogeneously distributed across the patches. It is shown here that this apparently paradoxical result is explained when the resultant differences in energy inputs to the whole multi-patch system are taken into account...
December 5, 2018: Theoretical Population Biology
William Gilpin, Marcus W Feldman
Individuals with different phenotypes can have widely-varying responses to natural selection, yet many classical approaches to evolutionary dynamics emphasize only how a population's average phenotype increases in fitness over time. However, recent experimental results have produced examples of populations that have multiple fitness peaks, or that experience frequency-dependence that affects the direction and strength of selection on certain individuals. Here, we extend classical fitness gradient formulations of natural selection in order to describe the dynamics of a phenotype distribution in terms of its moments-such as the mean, variance, and skewness...
December 4, 2018: Theoretical Population Biology
Yoav Ram, Uri Liberman, Marcus W Feldman
No abstract text is available yet for this article.
November 19, 2018: Theoretical Population Biology
Dalkhat M Ediev, Warren C Sanderson, Sergei Scherbov
Unlike other biological populations, the human population is experiencing long-run increases in life expectancy. Those lead to changes in age compositions not typical for other biological populations. Sanderson and Scherbov (2015a) demonstrated that, in many countries in Europe, faster increases in life expectancy lead to faster population aging when measured using the old-age dependency ratio and to slower population aging when measured using the prospective old-age dependency ratio that employs a dynamic old-age threshold...
November 14, 2018: Theoretical Population Biology
Peter Czuppon, Chaitanya S Gokhale
In population genetics, fixation of traits in a demographically changing population under frequency-independent selection has been extensively analysed. In evolutionary game theory, models of fixation have typically focused on fixed population sizes and frequency-dependent selection. A combination of demographic fluctuations with frequency-dependent interactions such as Lotka-Volterra dynamics has received comparatively little attention. We consider a stochastic, competitive Lotka-Volterra model with higher order interactions between two traits...
October 22, 2018: Theoretical Population Biology
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