scholarly journals Fixation in competing populations: Diffusion and strategies for survival

2020 ◽  
Vol 2 (2) ◽  
Author(s):  
Tapas Singha ◽  
Prasad Perlekar ◽  
Mustansir Barma
Keyword(s):  
Competing Populations

scholarly journals Modeling the ecology of parasitic plasmids

2021 ◽  
Author(s):  
Jaime G. Lopez ◽  
Mohamed S. Donia ◽  
Ned S. Wingreen
Keyword(s):  
Mathematical Modeling ◽  
Population Dynamics ◽  
Tragedy Of The Commons ◽  
Fitness Costs ◽  
Metapopulation Model ◽  
The Commons ◽  
Modern Biotechnology ◽  
Natural Ecology ◽  
Unique Plasmid ◽  
Competing Populations

AbstractPlasmids are autonomous genetic elements that can be exchanged between microorganisms via horizontal gene transfer (HGT). Despite the central role they play in antibiotic resistance and modern biotechnology, our understanding of plasmids’ natural ecology is limited. Recent experiments have shown that plasmids can spread even when they are a burden to the cell, suggesting that natural plasmids may exist as parasites. Here, we use mathematical modeling to explore the ecology of such parasitic plasmids. We first develop models of single plasmids and find that a plasmid’s population dynamics and optimal infection strategy are strongly determined by the plasmid’s HGT mechanism. We then analyze models of co-infecting plasmids and show that parasitic plasmids are prone to a “tragedy of the commons” in which runaway plasmid invasion severely reduces host fitness. We propose that this tragedy of the commons is averted by selection between competing populations and demonstrate this effect in a metapopulation model. We derive predicted distributions of unique plasmid types in genomes—comparison to the distribution of plasmids in a collection of 17,725 genomes supports a model of parasitic plasmids with positive plasmid–plasmid interactions that ameliorate plasmid fitness costs or promote the invasion of new plasmids.

scholarly journals Coevolving Predator and Prey Robots: Do “Arms Races” Arise in Artificial Evolution?

1998 ◽  
Vol 4 (4) ◽  
pp. 311-335 ◽  
Author(s):  
Stefano Nolfi ◽  
Dario Floreano
Keyword(s):  
Evolutionary Robotics ◽  
Arms Race ◽  
Artificial Evolution ◽  
Arms Races ◽  
Wide Range ◽  
Evolutionary Arms Race ◽  
Adaptive Power ◽  
Competing Populations

Coevolution (i.e., the evolution of two or more competing populations with coupled fitness) has several features that may potentially enhance the power of adaptation of artificial evolution. In particular, as discussed by Dawkins and Krebs [3], competing populations may reciprocally drive one another to increasing levels of complexity by producing an evolutionary “arms race.” In this article we will investigate the role of coevolution in the context of evolutionary robotics. In particular, we will try to understand in what conditions coevolution can lead to “arms races.” Moreover, we will show that in some cases artificial coevolution has a higher adaptive power than simple evolution. Finally, by analyzing the dynamics of coevolved populations, we will show that in some circumstances well-adapted individuals would be better advised to adopt simple but easily modifiable strategies suited for the current competitor strategies rather than incorporate complex and general strategies that may be effective against a wide range of opposing counter-strategies.

Spontaneous pattern formation and genetic invasion in locally mating and competing populations

2002 ◽  
Vol 65 (5) ◽  
Author(s):  
Hiroki Sayama ◽  
Marcus A. M. de Aguiar ◽  
Yaneer Bar-Yam ◽  
Michel Baranger
Keyword(s):  
Pattern Formation ◽  
Competing Populations

scholarly journals Coexistence and Noncoexistence of Markovian Viruses and their Hosts

2014 ◽  
Vol 51 (1) ◽  
pp. 191-208 ◽  
Author(s):  
Jakob E. Björnberg ◽  
Erik I. Broman
Keyword(s):  
Virus Infection ◽  
Predator Prey ◽  
Classic Problem ◽  
Infected Cells ◽  
Predator Prey Models ◽  
Two Populations ◽  
Competing Populations

Examining possibilities for the coexistence of two competing populations is a classic problem which dates back to the earliest ‘predator-prey’ models. In this paper we study this problem in the context of a model introduced in Björnberg et al. (2012) for the spread of a virus infection in a population of healthy cells. The infected cells may be seen as a population of ‘predators’ and the healthy cells as a population of ‘prey’. We show that, depending on the parameters defining the model, there may or may not be coexistence of the two populations, and we give precise criteria for this.

scholarly journals Coexistence and Noncoexistence of Markovian Viruses and their Hosts

2014 ◽  
Vol 51 (01) ◽  
pp. 191-208 ◽  
Author(s):  
Jakob E. Björnberg ◽  
Erik I. Broman
Keyword(s):  
Virus Infection ◽  
Predator Prey ◽  
Classic Problem ◽  
Infected Cells ◽  
Predator Prey Models ◽  
Two Populations ◽  
Competing Populations

Examining possibilities for the coexistence of two competing populations is a classic problem which dates back to the earliest ‘predator-prey’ models. In this paper we study this problem in the context of a model introduced in Björnberg et al. (2012) for the spread of a virus infection in a population of healthy cells. The infected cells may be seen as a population of ‘predators’ and the healthy cells as a population of ‘prey’. We show that, depending on the parameters defining the model, there may or may not be coexistence of the two populations, and we give precise criteria for this.

Chaotic Hierarchy in a Model of Competing Populations

1993 ◽  
Vol 165 (4) ◽  
pp. 593-607 ◽  
Author(s):  
Gerold Baier ◽  
Jesper S. Thomsen ◽  
Erik Mosekilde
Keyword(s):  
Competing Populations

TUMOR-IMMUNE SYSTEM INTERACTION: MODELING THE TUMOR-STIMULATED PROLIFERATION OF EFFECTORS AND IMMUNOTHERAPY

2006 ◽  
Vol 16 (08) ◽  
pp. 1375-1401 ◽  
Author(s):  
A. D'ONOFRIO
Keyword(s):  
Immune System ◽  
Tumor Cells ◽  
Local Stability ◽  
Tumor Burden ◽  
Stable Limit ◽  
Asymptotically Stable ◽  
Proliferation Response ◽  
Interaction Modeling ◽  
Stable Limit Cycles ◽  
Competing Populations

Tumoral dynamics and antitumor immunotherapies are likely to be influenced by the modalities of interaction between tumor cells and immune system effectors, and by the inter-effectors interactions. Within the framework of the theory of competing populations, we study here the influence of the proliferation response of effectors to tumor burden, and of cooperation and/or competition between immune system effectors, by means of three inter-related bi-dimensional meta-models. After studying their null-clines, we study the location and the local stability of the equilibria. Then, we investigate the existence and, in some cases, the uniqueness of stable limit cycles. The condition for the global asymptotically stable eradication under constant or slightly variable periodic immunotherapy is given. Finally, implications of strong saturation in the effectors ability to kill tumor cells are discussed.

The Numic Spread: A Computer Simulation

1992 ◽  
Vol 57 (1) ◽  
pp. 85-99 ◽  
Author(s):  
David A. Young ◽  
Robert L. Bettinger
Keyword(s):  
Mathematical Model ◽  
Computer Simulation ◽  
Spatial Distribution ◽  
Differential Equations ◽  
Diffusion Process ◽  
Great Basin ◽  
Demographic Variables ◽  
Migration Rates ◽  
Ethnographic Data ◽  
Competing Populations

We develop a mathematical model for the spread of Numic-speaking peoples across the Great Basin in the second millennium A.D., in accord with the ideas of Bettinger and Baumhoff (1982), who suggested a competitive interaction between the Numic and Prenumic peoples of the region. We construct differential equations representing two competing populations that spread by a diffusion process across an area representing the Great Basin. The demographic variables are fixed to agree with ethnographic data, while the migration rates are fitted to the estimated time for the completion of the spread. The model predicts a spatial distribution of the Numic languages in satisfactory agreement with observations and suggests new avenues of investigation.

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