Stationary distribution approximations of Two-island Wright-Fisher and seed-bank models using Stein's method

Fuente: arXiv
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Autores principales: Gan, Han L., Wilke-Berenguer, Maite
Formato: Preprint
Publicado: 2024
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author Gan, Han L.
Wilke-Berenguer, Maite
author_facet Gan, Han L.
Wilke-Berenguer, Maite
contents We consider two finite population Markov chain models, the two-island Wright-Fisher model with mutation, and the seed-bank model with mutation. Despite the relatively simple descriptions of the two processes, the the exact form of their stationary distributions is in general intractable. For each of the two models we provide two approximation theorems with explicit upper bounds on the distance between the stationary distributions of the finite population Markov chains, and either the stationary distribution of a two-island diffusion model, or the beta distribution. We show that the order of the bounds, and correspondingly the appropriate choice of approximation, depends upon the relative sizes of mutation and migration. In the case where migration and mutation are of the same order, the suitable approximation is the two-island diffusion model, and if migration dominates mutation, then the weighted average of both islands is well approximated by a beta random variable. Our results are derived from a new development of Stein's method for the stationary distribution of the two-island diffusion model for the weak migration results, and utilising the existing framework for Stein's method for the Dirichlet distribution.
format Preprint
id arxiv_https___arxiv_org_abs_2405_18763
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Stationary distribution approximations of Two-island Wright-Fisher and seed-bank models using Stein's method
Gan, Han L.
Wilke-Berenguer, Maite
Probability
Populations and Evolution
92D25, 60F05, 60J95
We consider two finite population Markov chain models, the two-island Wright-Fisher model with mutation, and the seed-bank model with mutation. Despite the relatively simple descriptions of the two processes, the the exact form of their stationary distributions is in general intractable. For each of the two models we provide two approximation theorems with explicit upper bounds on the distance between the stationary distributions of the finite population Markov chains, and either the stationary distribution of a two-island diffusion model, or the beta distribution. We show that the order of the bounds, and correspondingly the appropriate choice of approximation, depends upon the relative sizes of mutation and migration. In the case where migration and mutation are of the same order, the suitable approximation is the two-island diffusion model, and if migration dominates mutation, then the weighted average of both islands is well approximated by a beta random variable. Our results are derived from a new development of Stein's method for the stationary distribution of the two-island diffusion model for the weak migration results, and utilising the existing framework for Stein's method for the Dirichlet distribution.
title Stationary distribution approximations of Two-island Wright-Fisher and seed-bank models using Stein's method
topic Probability
Populations and Evolution
92D25, 60F05, 60J95
url https://arxiv.org/abs/2405.18763