---
_id: '3668'
abstract:
- lang: eng
  text: When two populations which differ at many loci meet, the degree of introgression
    of alleles across the boundary will depend on the selection acting on each locus
    (s), the rate of recombination between adjacent loci (r), and the number of loci
    involved (n). Simple scaling arguments suggest that the behavior of the system
    should depend on the ratio of selection to recombination (θ = s/r), and on n.
    This is borne out by mathematical analysis of two demes which exchange individuals
    at a low rate; when selection is stronger than recombination (θ > 1), the effective
    selection on each locus is comparable to the total selection over the whole genome
    (s* ∼ ns). When selection is weaker than recombination (θ < 1), the effective
    selection is much weaker, but is still stronger than the selection on each locus
    alone (s* \sim sn20 for small θ). When n is very large, these two regimes are
    separated by a sharp threshold at θ = 1. The results are extended to two taxa
    which meet in a continuous habitat; the effective selection pressure, which determines
    the width of the hybrid zone, behaves in the same way as for the simpler case
    above. Even when selection is weak compared to recombination, multilocus clines
    have a sharp step at their center, flanked by tails of introgression in which
    the alleles behave independently of each other. The set of clines acts as a barrier
    to gene flow, and it is shown that the barrier is strongest when selection is
    spread over many loci. The implications of the results for divergence and speciation
    are discussed.
acknowledgement: "I would like to thank G. Hewitt, J. Raper, M. Shaw, P. Oliver, M.
  Slatkin, J. Felsenstein, and D. J. Futuyma for their\r\n helpful comments. This
  work was partly supported by an SRC Post-Doctoral Fellowship."
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
citation:
  ama: Barton NH. Multilocus clines. <i>Evolution; International Journal of Organic
    Evolution</i>. 1983;37(3):454-471. doi:<a href="https://doi.org/10.2307/2408260">10.2307/2408260</a>
  apa: Barton, N. H. (1983). Multilocus clines. <i>Evolution; International Journal
    of Organic Evolution</i>. Society for the Study of Evolution. <a href="https://doi.org/10.2307/2408260">https://doi.org/10.2307/2408260</a>
  chicago: Barton, Nicholas H. “Multilocus Clines.” <i>Evolution; International Journal
    of Organic Evolution</i>. Society for the Study of Evolution, 1983. <a href="https://doi.org/10.2307/2408260">https://doi.org/10.2307/2408260</a>.
  ieee: N. H. Barton, “Multilocus clines,” <i>Evolution; International Journal of
    Organic Evolution</i>, vol. 37, no. 3. Society for the Study of Evolution, pp.
    454–471, 1983.
  ista: Barton NH. 1983. Multilocus clines. Evolution; International Journal of Organic
    Evolution. 37(3), 454–471.
  mla: Barton, Nicholas H. “Multilocus Clines.” <i>Evolution; International Journal
    of Organic Evolution</i>, vol. 37, no. 3, Society for the Study of Evolution,
    1983, pp. 454–71, doi:<a href="https://doi.org/10.2307/2408260">10.2307/2408260</a>.
  short: N.H. Barton, Evolution; International Journal of Organic Evolution 37 (1983)
    454–471.
date_created: 2018-12-11T12:04:31Z
date_published: 1983-05-01T00:00:00Z
date_updated: 2022-08-19T07:08:29Z
day: '01'
doi: 10.2307/2408260
extern: '1'
external_id:
  pmid:
  - '28563316 '
intvolume: '        37'
issue: '3'
language:
- iso: eng
main_file_link:
- url: http://www.jstor.org/stable/2408260
month: '05'
oa_version: None
page: 454 - 471
pmid: 1
publication: Evolution; International Journal of Organic Evolution
publication_identifier:
  eissn:
  - 1558-5646
  issn:
  - 0014-3820
publication_status: published
publisher: Society for the Study of Evolution
publist_id: '2715'
quality_controlled: '1'
status: public
title: Multilocus clines
type: journal_article
user_id: 3E5EF7F0-F248-11E8-B48F-1D18A9856A87
volume: 37
year: '1983'
...