---
_id: '4303'
abstract:
- lang: eng
text: In a stably subdivided population with symmetric migration, the chance that
a favoured allele will be fixed is independent of population structure. However,
random extinction introduces an extra component of sampling drift, and reduces
the probability of fixation. In this paper, the fixation probability is calculated
using the diffusion approximation; comparison with exact solution of the discrete
model shows this to be accurate. The key parameters are the rates of selection,
migration and extinction, scaled relative to population size (S = 4Ns, M = 4Nm,
Λ = 4Nλ); results apply to a haploid model, or to diploids with additive selection.
If new colonies derive from many demes, the fixation probability cannot be reduced
by more than half. However, if colonies are initially homogeneous, fixation probability
can be much reduced. In the limit of low migration and extinction rates (M, Λ
1), it is 2s/{1 + (Λ/MS)(1 −exp(−S))}, whilst in the opposite limit (S 1), it
is 4sM/{Λ(Λ + M)}. In the limit of weak selection (M, Λ 1), it is 4sM/{Λ(Λ +
M)}. These factors are not the same as the reduction in effective population size
(Ne/N), showing that the effects of population structure on selected alleles cannot
be understood from the behaviour of neutral markers.
author:
- first_name: Nicholas H
full_name: Nicholas Barton
id: 4880FE40-F248-11E8-B48F-1D18A9856A87
last_name: Barton
orcid: 0000-0002-8548-5240
citation:
ama: Barton NH. The probability of fixation of a favoured allele in a subdivided
population. *Genetical Research*. 1993;62(2):149-158. doi:10.1017/S0016672300031748
apa: Barton, N. H. (1993). The probability of fixation of a favoured allele in a
subdivided population. *Genetical Research*. Cambridge University Press.
https://doi.org/10.1017/S0016672300031748
chicago: Barton, Nicholas H. “The Probability of Fixation of a Favoured Allele in
a Subdivided Population.” *Genetical Research*. Cambridge University Press,
1993. https://doi.org/10.1017/S0016672300031748.
ieee: N. H. Barton, “The probability of fixation of a favoured allele in a subdivided
population,” *Genetical Research*, vol. 62, no. 2. Cambridge University Press,
pp. 149–158, 1993.
ista: Barton NH. 1993. The probability of fixation of a favoured allele in a subdivided
population. Genetical Research. 62(2), 149–158.
mla: Barton, Nicholas H. “The Probability of Fixation of a Favoured Allele in a
Subdivided Population.” *Genetical Research*, vol. 62, no. 2, Cambridge University
Press, 1993, pp. 149–58, doi:10.1017/S0016672300031748.
short: N.H. Barton, Genetical Research 62 (1993) 149–158.
date_created: 2018-12-11T12:08:09Z
date_published: 1993-10-01T00:00:00Z
date_updated: 2021-01-12T07:55:59Z
day: '01'
doi: 10.1017/S0016672300031748
extern: 1
intvolume: ' 62'
issue: '2'
month: '10'
page: 149 - 158
publication: Genetical Research
publication_status: published
publisher: Cambridge University Press
publist_id: '1762'
quality_controlled: 0
status: public
title: The probability of fixation of a favoured allele in a subdivided population
type: journal_article
volume: 62
year: '1993'
...