---
_id: '3657'
abstract:
- lang: eng
  text: Shifts between adaptive peaks, caused by sampling drift, are involved in both
    speciation and adaptation via Wright's “shiftingbalance.” We use techniques from
    statistical mechanics to calculate the rate of such transitions for apopulation
    in a single panmictic deme and for apopulation which is continuously distributed
    over one- and two-dimensional regions. This calculation applies in the limit where
    transitions are rare. Our results indicate that stochastic divergence is feasible
    despite free gene flow, provided that neighbourhood size is low enough. In two
    dimensions, the rate of transition depends primarily on neighbourhood size N and
    only weakly on selection pressure (≈sk exp(− cN)), where k is a number determined
    by the local population structure, in contrast with the exponential dependence
    on selection pressure in one dimension (≈exp(− cN √s)) or in a single deme (≈exp(−
    cNs)). Our calculations agree with simulations of a single deme and a one-dimensional
    population.
acknowledgement: "We thank M. Shaw, J. Felsenstein, M. Kirkpatrick, S. Via, J. S.
  Jones, M. Slatkin, J. Mallet, and B. Charlesworth for their helpful comments. This
  work was supported by grants from the SERC (GR/C/91529), the University of London
  Central Research Fund, and the Nufield Foundation. \r\n"
article_processing_charge: No
article_type: original
author:
- first_name: Shahin
  full_name: Rouhani, Shahin
  last_name: Rouhani
- first_name: Nicholas H
  full_name: Barton, Nicholas H
  id: 4880FE40-F248-11E8-B48F-1D18A9856A87
  last_name: Barton
  orcid: 0000-0002-8548-5240
citation:
  ama: Rouhani S, Barton NH. Speciation and the "shifting balance"
    in a continuous population. <i>Theoretical Population Biology</i>. 1987;31(3):465-492.
    doi:<a href="https://doi.org/10.1016/0040-5809(87)90016-5">10.1016/0040-5809(87)90016-5</a>
  apa: Rouhani, S., &#38; Barton, N. H. (1987). Speciation and the &#38;quot;shifting
    balance&#38;quot; in a continuous population. <i>Theoretical Population Biology</i>.
    Elsevier. <a href="https://doi.org/10.1016/0040-5809(87)90016-5">https://doi.org/10.1016/0040-5809(87)90016-5</a>
  chicago: Rouhani, Shahin, and Nicholas H Barton. “Speciation and the &#38;quot;Shifting
    Balance&#38;quot; in a Continuous Population.” <i>Theoretical Population Biology</i>.
    Elsevier, 1987. <a href="https://doi.org/10.1016/0040-5809(87)90016-5">https://doi.org/10.1016/0040-5809(87)90016-5</a>.
  ieee: S. Rouhani and N. H. Barton, “Speciation and the &#38;quot;shifting balance&#38;quot;
    in a continuous population,” <i>Theoretical Population Biology</i>, vol. 31, no.
    3. Elsevier, pp. 465–492, 1987.
  ista: Rouhani S, Barton NH. 1987. Speciation and the &#38;quot;shifting balance&#38;quot;
    in a continuous population. Theoretical Population Biology. 31(3), 465–492.
  mla: Rouhani, Shahin, and Nicholas H. Barton. “Speciation and the &#38;quot;Shifting
    Balance&#38;quot; in a Continuous Population.” <i>Theoretical Population Biology</i>,
    vol. 31, no. 3, Elsevier, 1987, pp. 465–92, doi:<a href="https://doi.org/10.1016/0040-5809(87)90016-5">10.1016/0040-5809(87)90016-5</a>.
  short: S. Rouhani, N.H. Barton, Theoretical Population Biology 31 (1987) 465–492.
date_created: 2018-12-11T12:04:28Z
date_published: 1987-06-01T00:00:00Z
date_updated: 2022-02-04T12:30:10Z
day: '01'
doi: 10.1016/0040-5809(87)90016-5
extern: '1'
intvolume: '        31'
issue: '3'
language:
- iso: eng
main_file_link:
- url: https://www.sciencedirect.com/science/article/pii/0040580987900165?via%3Dihub
month: '06'
oa_version: None
page: 465 - 492
publication: Theoretical Population Biology
publication_identifier:
  eissn:
  - 1096-0325
  issn:
  - 0040-5809
publication_status: published
publisher: Elsevier
publist_id: '2726'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Speciation and the &quot;shifting balance&quot; in a continuous population
type: journal_article
user_id: ea97e931-d5af-11eb-85d4-e6957dddbf17
volume: 31
year: '1987'
...
---
_id: '3662'
abstract:
- lang: eng
  text: The evolution of the probabilities of genetic identity within and between
    tandemly repeated loci of a multigene family is investigated analytically and
    numerically. Unbiased intrachromosomal gene conversion, equal crossing over, random
    genetic drift, and mutation to new alleles are incorporated. Generations are discrete
    and nonoverlapping; the diploid, monoecious population mates at random. Under
    the restriction that there is at most one crossover in the multigene family per
    individual per generation, the dependence on location of the probabilities of
    identity is treated exactly. In the “homogeneous” approximation to this “exact”
    model, end effects are disregarded; in the “exchangeable” approximation, to which
    all previous work was confined, all position dependence is neglected. Numerical
    results indicate that (i) the exchangeable and homogeneous models are both qualitatively
    correct, (ii) the exchangeable model is sometimes too inaccurate for quantitative
    conclusions, and (iii) the homogeneous model is always more accurate than the
    exchangeable one and is always sufficiently accurate for quantitative conclusions.
acknowledgement: Supported by National Science Foundation Grant DEB81-03530
article_processing_charge: No
article_type: original
author:
- first_name: Thomas
  full_name: Nagylaki, Thomas
  last_name: Nagylaki
- first_name: Nicholas H
  full_name: Barton, Nicholas H
  id: 4880FE40-F248-11E8-B48F-1D18A9856A87
  last_name: Barton
  orcid: 0000-0002-8548-5240
citation:
  ama: Nagylaki T, Barton NH. Intrachromosomal gene conversion, linkage, and the evolution
    of multigene families. <i>Theoretical Population Biology</i>. 1986;29(3):407-437.
    doi:<a href="https://doi.org/10.1016/0040-5809(86)90017-1">10.1016/0040-5809(86)90017-1</a>
  apa: Nagylaki, T., &#38; Barton, N. H. (1986). Intrachromosomal gene conversion,
    linkage, and the evolution of multigene families. <i>Theoretical Population Biology</i>.
    Academic Press. <a href="https://doi.org/10.1016/0040-5809(86)90017-1">https://doi.org/10.1016/0040-5809(86)90017-1</a>
  chicago: Nagylaki, Thomas, and Nicholas H Barton. “Intrachromosomal Gene Conversion,
    Linkage, and the Evolution of Multigene Families.” <i>Theoretical Population Biology</i>.
    Academic Press, 1986. <a href="https://doi.org/10.1016/0040-5809(86)90017-1">https://doi.org/10.1016/0040-5809(86)90017-1</a>.
  ieee: T. Nagylaki and N. H. Barton, “Intrachromosomal gene conversion, linkage,
    and the evolution of multigene families,” <i>Theoretical Population Biology</i>,
    vol. 29, no. 3. Academic Press, pp. 407–437, 1986.
  ista: Nagylaki T, Barton NH. 1986. Intrachromosomal gene conversion, linkage, and
    the evolution of multigene families. Theoretical Population Biology. 29(3), 407–437.
  mla: Nagylaki, Thomas, and Nicholas H. Barton. “Intrachromosomal Gene Conversion,
    Linkage, and the Evolution of Multigene Families.” <i>Theoretical Population Biology</i>,
    vol. 29, no. 3, Academic Press, 1986, pp. 407–37, doi:<a href="https://doi.org/10.1016/0040-5809(86)90017-1">10.1016/0040-5809(86)90017-1</a>.
  short: T. Nagylaki, N.H. Barton, Theoretical Population Biology 29 (1986) 407–437.
date_created: 2018-12-11T12:04:30Z
date_published: 1986-06-01T00:00:00Z
date_updated: 2022-02-01T15:50:10Z
day: '01'
doi: 10.1016/0040-5809(86)90017-1
extern: '1'
intvolume: '        29'
issue: '3'
language:
- iso: eng
month: '06'
oa_version: None
page: 407 - 437
publication: Theoretical Population Biology
publication_identifier:
  eissn:
  - 1096-0325
  issn:
  - 0040-5809
publication_status: published
publisher: Academic Press
publist_id: '2721'
quality_controlled: '1'
scopus_import: '1'
status: public
title: Intrachromosomal gene conversion, linkage, and the evolution of multigene families
type: journal_article
user_id: ea97e931-d5af-11eb-85d4-e6957dddbf17
volume: 29
year: '1986'
...