Multi-type $Ξ$-coalescents from structured population models with bottlenecks

Fuente: arXiv
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Auteurs principaux: Pra, Marta Dai, Etheridge, Alison, Koskela, Jere, Wilke-Berenguer, Maite
Format: Preprint
Publié: 2025
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author Pra, Marta Dai
Etheridge, Alison
Koskela, Jere
Wilke-Berenguer, Maite
author_facet Pra, Marta Dai
Etheridge, Alison
Koskela, Jere
Wilke-Berenguer, Maite
contents We introduce an individual-based model for structured populations undergoing demographic bottlenecks, i.e. drastic reductions in population size that last many generations and can have arbitrary shapes. We first show that the (non-Markovian) allele-frequency process converges to a Markovian diffusion process with jumps in a suitable relaxation of the Skorokhod J1 topology. Backward in time we find that genealogies of samples of individuals are described by multi-type $Ξ$-coalescents presenting multiple simultaneous mergers with simultaneous migrations. These coalescents are also moment-duals of the limiting jump diffusions. We then show through a numerical study that our model is flexible and can predict various shapes for the site frequency spectrum, consistent with real data, using a small number of interpretable parameters.
format Preprint
id arxiv_https___arxiv_org_abs_2504_11875
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Multi-type $Ξ$-coalescents from structured population models with bottlenecks
Pra, Marta Dai
Etheridge, Alison
Koskela, Jere
Wilke-Berenguer, Maite
Probability
Populations and Evolution
60K35, 60J90, 60J70
We introduce an individual-based model for structured populations undergoing demographic bottlenecks, i.e. drastic reductions in population size that last many generations and can have arbitrary shapes. We first show that the (non-Markovian) allele-frequency process converges to a Markovian diffusion process with jumps in a suitable relaxation of the Skorokhod J1 topology. Backward in time we find that genealogies of samples of individuals are described by multi-type $Ξ$-coalescents presenting multiple simultaneous mergers with simultaneous migrations. These coalescents are also moment-duals of the limiting jump diffusions. We then show through a numerical study that our model is flexible and can predict various shapes for the site frequency spectrum, consistent with real data, using a small number of interpretable parameters.
title Multi-type $Ξ$-coalescents from structured population models with bottlenecks
topic Probability
Populations and Evolution
60K35, 60J90, 60J70
url https://arxiv.org/abs/2504.11875