Scaling limits of a model for selection at two scales Joint with Shishi Luo

54 mins 15 secs,  778.15 MB,  MPEG-4 Video  640x360,  29.97 fps,  44100 Hz,  1.91 Mbits/sec
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Description: Mattingly, J
Friday 10th June 2016 - 11:00 to 12:00
 
Created: 2016-06-28 13:48
Collection: Stochastic Dynamical Systems in Biology: Numerical Methods and Applications
Publisher: Isaac Newton Institute
Copyright: Mattingly, J
Language: eng (English)
Distribution: World     (downloadable)
Explicit content: No
Aspect Ratio: 16:9
Screencast: No
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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, λ. We show that the fixed points of this differential equation are Beta distributions and that their stability depends on λ 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.
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