{ "id": "1507.00397", "version": "v1", "published": "2015-07-02T00:08:34.000Z", "updated": "2015-07-02T00:08:34.000Z", "title": "Scaling limits of a model for selection at two scales", "authors": [ "Shishi Luo", "Jonathan C. Mattingly" ], "comment": "23 pages, 1 figure", "categories": [ "math.PR", "math.DS" ], "abstract": "The dynamics of a population undergoing selection is a central topic in evolutionary biology. This question is particularly intriguing in the case where selective forces act in opposing directions at two population scales. For example, a fast-replicating virus strain outcompetes slower-replicating strains at the within-host scale. However, if the fast-replicating strain causes host morbidity and is less frequently transmitted, it can be outcompeted by slower-replicating strains at the between-host scale. Here we consider a stochastic ball-and-urn process which models this type of phenomenon. We prove the weak convergence of this process under two natural scalings. The first scaling leads to a deterministic nonlinear integro-partial differential equation on the interval $[0,1]$ with dependence on a single parameter, $\\lambda$. We show that the fixed points of this differential equation are Beta distributions and that their stability depends on $\\lambda$ and the behavior of the initial data around $1$. The second scaling leads to a measure-valued Fleming-Viot process, an infinite dimensional stochastic process that is frequently associated with a population genetics.", "revisions": [ { "version": "v1", "updated": "2015-07-02T00:08:34.000Z" } ], "analyses": { "keywords": [ "scaling limits", "deterministic nonlinear integro-partial differential equation", "virus strain outcompetes slower-replicating strains", "infinite dimensional stochastic process" ], "note": { "typesetting": "TeX", "pages": 23, "language": "en", "license": "arXiv", "status": "editable" } } }