---
_id: '4328'
abstract:
- lang: eng
  text: The hybrid zone which forms when two partially incompatible populations meet
    acts as a barrier to gene flow. We discuss electrophoretic and theoretical evidence
    on the strength of such barriers. Hybrid zones generally involve considerable
    electrophoretic divergence. The enzyme clines are consistent in position and width;
    in some cases, they show consistently asymmetric patterns of introgression. This
    consistency suggests that the clines are maintained primarily by the indirect
    effects of selection at linked loci, rather than by the effect of each individual
    locus on fitness. A cline at a single locus will present some barrier, regardless
    of the selective mechanism which maintains it. However, unless the locus induces
    virtually complete assortment or hybrid unfitness, the barrier will be weak. Spreading
    the same selection over more clines gives a stronger barrier. If the clines are
    staggered, this barrier is still unlikely to be significant; if they coincide,
    and if selection is stronger than recombination, then the barrier will be very
    strong; its strength and asymmetry will be consistent over different loci. Thus,
    the taxonomic status of divergent populations cannot be inferred just from the
    total amount of pre- or post-mating isolation; the number of genetic differences,
    and the interactions between them are equally important in determining rates of
    gene flow.
alternative_title:
- Systematics Association Special Volume
article_processing_charge: No
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: Godfrey
  full_name: Hewitt, Godfrey
  last_name: Hewitt
citation:
  ama: 'Barton NH, Hewitt G. Hybrid zones as barriers to gene flow. In: Oxford G,
    Rollinson D, eds. <i>Protein Polymorphism: Adaptive and Taxonomic Significance</i>.
    Vol 24. Academic Press; 1983:341-359.'
  apa: 'Barton, N. H., &#38; Hewitt, G. (1983). Hybrid zones as barriers to gene flow.
    In G. Oxford &#38; D. Rollinson (Eds.), <i>Protein polymorphism: Adaptive and
    taxonomic significance</i> (Vol. 24, pp. 341–359). University of York, United
    Kingdom: Academic Press.'
  chicago: 'Barton, Nicholas H, and Godfrey Hewitt. “Hybrid Zones as Barriers to Gene
    Flow.” In <i>Protein Polymorphism: Adaptive and Taxonomic Significance</i>, edited
    by Geoffrey Oxford and David Rollinson, 24:341–59. Academic Press, 1983.'
  ieee: 'N. H. Barton and G. Hewitt, “Hybrid zones as barriers to gene flow,” in <i>Protein
    polymorphism: Adaptive and taxonomic significance</i>, vol. 24, G. Oxford and
    D. Rollinson, Eds. Academic Press, 1983, pp. 341–359.'
  ista: 'Barton NH, Hewitt G. 1983.Hybrid zones as barriers to gene flow. In: Protein
    polymorphism: Adaptive and taxonomic significance. Systematics Association Special
    Volume, vol. 24, 341–359.'
  mla: 'Barton, Nicholas H., and Godfrey Hewitt. “Hybrid Zones as Barriers to Gene
    Flow.” <i>Protein Polymorphism: Adaptive and Taxonomic Significance</i>, edited
    by Geoffrey Oxford and David Rollinson, vol. 24, Academic Press, 1983, pp. 341–59.'
  short: 'N.H. Barton, G. Hewitt, in:, G. Oxford, D. Rollinson (Eds.), Protein Polymorphism:
    Adaptive and Taxonomic Significance, Academic Press, 1983, pp. 341–359.'
conference:
  end_date: 1982-07-15
  location: University of York, United Kingdom
  name: 'SystAss: Systematics Association'
  start_date: 1982-07-13
date_created: 2018-12-11T12:08:17Z
date_published: 1983-01-01T00:00:00Z
date_updated: 2022-01-24T11:05:31Z
day: '01'
editor:
- first_name: Geoffrey
  full_name: Oxford, Geoffrey
  last_name: Oxford
- first_name: David
  full_name: Rollinson, David
  last_name: Rollinson
extern: '1'
intvolume: '        24'
keyword:
- chemotaxonomy
language:
- iso: eng
month: '01'
oa_version: None
page: 341 - 359
publication: 'Protein polymorphism: Adaptive and taxonomic significance'
publication_identifier:
  isbn:
  - 978-0-1253-1780-1
  issn:
  - 0309-2593
publication_status: published
publisher: Academic Press
publist_id: '1710'
quality_controlled: '1'
status: public
title: Hybrid zones as barriers to gene flow
type: book_chapter
user_id: 8b945eb4-e2f2-11eb-945a-df72226e66a9
volume: 24
year: '1983'
...