---
_id: '3663'
abstract:
- lang: eng
  text: The conditional average frequency of rare alleles has been shown in simulations
    to provide a simple and robust estimator of the number of individuals exchanged
    between local populations in an island model (Nm). This statistic is defined as
    the average frequency of an allele in those samples in which the allele is present.
    Here, we show that the conditional average frequency can be calculated from the
    distribution of allele frequencies. It is a measure of the spread of this distribution,
    and so is analogous to the standardised variance, FST. Analytic predictions for
    the island model of migration agree well with the corresponding simulation results.
    These predictions are based on the assumption that the rare alleles found in samples
    have reached a "quasi-equilibrium" distribution. As well as relating
    the conditional average frequency to the underlying allele frequency distribution,
    our results provide a more accurate method of estimating Nm from the conditional
    average frequency of private alleles in samples of different sizes.
acknowledgement: This research has been supported in part by grants from the Royal
  Society of London, S.E.R.C., and the National Science Foundation. We thank J. Felsenstein
  for helpful discussions of this problem.
article_processing_charge: No
article_type: original
author:
- first_name: Nicholas H
  full_name: Barton, Nicholas H
  id: 4880FE40-F248-11E8-B48F-1D18A9856A87
  last_name: Barton
  orcid: 0000-0002-8548-5240
- first_name: Montgomery
  full_name: Slatkin, Montgomery
  last_name: Slatkin
citation:
  ama: Barton NH, Slatkin M. A quasi-equilibrium theory of the distribution of rare
    alleles in a subdivided population. <i>Heredity</i>. 1986;56(3):409-416. doi:<a
    href="https://doi.org/10.1038/hdy.1986.63">10.1038/hdy.1986.63</a>
  apa: Barton, N. H., &#38; Slatkin, M. (1986). A quasi-equilibrium theory of the
    distribution of rare alleles in a subdivided population. <i>Heredity</i>. Nature
    Publishing Group. <a href="https://doi.org/10.1038/hdy.1986.63">https://doi.org/10.1038/hdy.1986.63</a>
  chicago: Barton, Nicholas H, and Montgomery Slatkin. “A Quasi-Equilibrium Theory
    of the Distribution of Rare Alleles in a Subdivided Population.” <i>Heredity</i>.
    Nature Publishing Group, 1986. <a href="https://doi.org/10.1038/hdy.1986.63">https://doi.org/10.1038/hdy.1986.63</a>.
  ieee: N. H. Barton and M. Slatkin, “A quasi-equilibrium theory of the distribution
    of rare alleles in a subdivided population,” <i>Heredity</i>, vol. 56, no. 3.
    Nature Publishing Group, pp. 409–416, 1986.
  ista: Barton NH, Slatkin M. 1986. A quasi-equilibrium theory of the distribution
    of rare alleles in a subdivided population. Heredity. 56(3), 409–416.
  mla: Barton, Nicholas H., and Montgomery Slatkin. “A Quasi-Equilibrium Theory of
    the Distribution of Rare Alleles in a Subdivided Population.” <i>Heredity</i>,
    vol. 56, no. 3, Nature Publishing Group, 1986, pp. 409–16, doi:<a href="https://doi.org/10.1038/hdy.1986.63">10.1038/hdy.1986.63</a>.
  short: N.H. Barton, M. Slatkin, Heredity 56 (1986) 409–416.
date_created: 2018-12-11T12:04:30Z
date_published: 1986-06-01T00:00:00Z
date_updated: 2022-02-01T15:04:01Z
day: '01'
doi: 10.1038/hdy.1986.63
extern: '1'
external_id:
  pmid:
  - '3733460 '
intvolume: '        56'
issue: '3'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://www.nature.com/articles/hdy198663
month: '06'
oa: 1
oa_version: None
page: 409 - 416
pmid: 1
publication: Heredity
publication_identifier:
  eissn:
  - 1365-2540
  issn:
  - 0018-067X
publication_status: published
publisher: Nature Publishing Group
publist_id: '2720'
quality_controlled: '1'
scopus_import: '1'
status: public
title: A quasi-equilibrium theory of the distribution of rare alleles in a subdivided
  population
type: journal_article
user_id: ea97e931-d5af-11eb-85d4-e6957dddbf17
volume: 56
year: '1986'
...