Summary
This paper investigates the dynamic behaviour of hybrid zones which are maintained by a balance between dispersal and selection against hybrids. In the first section it is shown that a hybrid zone involving a single locus can move in response to a selective imbalance between the two homozygotes, and also to variation in population density and dispersal rate. It can be trapped by natural barriers, and so an allele which is selected against when rare cannot advance, even if it is advantageous when common. The continuous model used in deriving these results is shown to be a good approximation to the stepping-stone model, provided that the cline contains several demes.
The effect of stochastic forces on multi-locus hybrid zones is then considered. An expression giving the shift in position after an arbitrary perturbation in gamete frequency is derived. Using this formula, it is found that sampling drift is negligible unless the zone includes few organisms and involves few loci. Random variations in population structure are the dominant force, and could allow considerable movement in an even environment. However, natural barriers can still trap hybrid zones, and so it is likely that they will remain roughly where they first formed.
Similar content being viewed by others
Article PDF
References
Barton, N H, and Hewitt, G M. 1980. Hybrid zones and speciation. In Essays on Evolution and Speciation in Honour of M J D White, eds. W. R. Atchley, D. S. Woodruff. Cambridge Univ. Press (in press).
Bazykin, A D. 1969. A hypothetical mechanism of speciation. Evolution, 23, 685–687.
Bazykin, A D. 1972. Disadvantage of heterozygotes in a population within a continuous area. Genetika, 8, 162–167.
Bazykin, A D. 1973. Population genetic analyses of disruptive and stabilizing selection. II. Systems of adjacent populations and populations within a continuous area. Genetika, 9, 156–166.
Crow, J F, and Kimura, M. 1970. An Introduction to Population Genetics Theory. Harper and Row.
Fisher, R A. 1937. The wave of advance of an advantageous gene. Ann Eugen, 7, 355–369.
Hadeler, K P. 1976. Travelling population fronts. In Population Genetics and Ecology, eds. S. Karlin, E. Nevo. Academic Press.
Karlin, S, and McGregor, J. 1972. Application of the method of small parameters to multi-niche population genetic models. Theor Pop Biol, 3, 186–209.
Key, K. 1974. Speciation in the Australian Morabine grasshoppers. In Genetic Mechanisms of Speciation in Insects, ed. M. J. D. White. Aust. and New Zealand Book Co.
Moore, W S. 1977. An evaluation of narrow hybrid zones in vertebrates. Quart Rev Biol, 52, 263–277.
Nagylaki, T. 1975. Conditions for the existence of clines. Genetics, 80, 595–615.
Nagylaki, T. 1978. Random genetic drift in a cline. Proc Natl Acad Sci, USA, 75, 423–426.
Soong, T T. 1973. Random Differential Equations. Academic Press.
Stokes, A N. 1976. On two types of moving front in quasilinear diffusion. Math Biosci, 31, 307–315.
White, M J D. 1968. Models of speciation. Science, 159, 1065–1070.
White, M J D. 1978. Modes of Speciation. W. H. Freeman Ltd.
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Barton, N. The dynamics of hybrid zones. Heredity 43, 341–359 (1979). https://doi.org/10.1038/hdy.1979.87
Received:
Issue Date:
DOI: https://doi.org/10.1038/hdy.1979.87
This article is cited by
-
Are there hybrid zones in Fagus sylvatica L. sensu lato?
European Journal of Forest Research (2024)
-
Pulled, pushed or failed: the demographic impact of a gene drive can change the nature of its spatial spread
Journal of Mathematical Biology (2023)
-
The spatio-temporal dynamics of interacting genetic incompatibilities. Part I: the case of stacked underdominant clines
Journal of Mathematical Biology (2022)
-
Transcriptome-wide analysis of introgression-resistant regions reveals genetic divergence genes under positive selection in Populus trichocarpa
Heredity (2021)
-
Demographic feedbacks can hamper the spatial spread of a gene drive
Journal of Mathematical Biology (2021)