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Speciation along environmental gradients

Nature volume 421, pages 259264 (16 January 2003) | Download Citation

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Abstract

Traditional discussions of speciation are based on geographical patterns of species ranges1,2. In allopatric speciation, long-term geographical isolation generates reproductively isolated and spatially segregated descendant species1,3. In the absence of geographical barriers, diversification is hindered by gene flow1,3,4. Yet a growing body of phylogenetic and experimental data suggests that closely related species often occur in sympatry or have adjacent ranges in regions over which environmental changes are gradual and do not prevent gene flow5,6,7,8,9,10,11,12,13,14. Theory has identified a variety of evolutionary processes that can result in speciation under sympatric conditions15,16,17,18,19,20,21,22,23,24,25, with some recent advances concentrating on the phenomenon of evolutionary branching18,23,24,25. Here we establish a link between geographical patterns and ecological processes of speciation by studying evolutionary branching in spatially structured populations. We show that along an environmental gradient, evolutionary branching can occur much more easily than in non-spatial models. This facilitation is most pronounced for gradients of intermediate slope. Moreover, spatial evolutionary branching readily generates patterns of spatial segregation and abutment between the emerging species. Our results highlight the importance of local processes of adaptive divergence for geographical patterns of speciation, and caution against pitfalls of inferring past speciation processes from present biogeographical patterns.

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References

  1. 1.

    Animal Species and Evolution (Harvard Univ. Press, Cambridge, Massachusetts, 1963)

  2. 2.

    Geographic Variation, Speciation, and Clines (Princeton Univ. Press, Princeton, New Jersey, 1977)

  3. 3.

    Genetics and speciation. Nature 355, 511–515 (1992)

  4. 4.

    Scepticism towards Santa Rosalia, or why are there so few kinds of animals. Evolution 35, 124–138 (1981)

  5. 5.

    , & Sympatric speciation suggested by monophyly of crater lake cichlids. Nature 368, 629–632 (1994)

  6. 6.

    Experimental evidence that competition promotes divergence in adaptive radiation. Science 266, 798–801 (1994)

  7. 7.

    , & Incipient reproductive isolation between two sympatric morphs of the intertidal snail Littorina saxatilis. Evolution 49, 1180–1190 (1995)

  8. 8.

    & Chloroplast DNA variation and the recent radiation of giant senecios (Asteraceae) on the tall mountains of Eastern Africa. Proc. Natl Acad. Sci. USA 92, 10349–10353 (1995)

  9. 9.

    Endless Forms (eds Howard, D. J. & Berlocher, S. H.) 130–144 (Oxford Univ. Press, Oxford, UK, 1998)

  10. 10.

    & Adaptive radiation in a heterogeneous environment. Nature 394, 69–72 (1998)

  11. 11.

    , , & Rapid and coupled phenotypic and genetic divergence in Icelandic Arctic char (Salvelinus alpinus). Can. J. Fish. Aquat. Sci. 56, 2229–2234 (1999)

  12. 12.

    , , , & Genetic and ecological divergence of a monophyletic cichlid species pair under fully sympatric conditions in Lake Ejagham, Cameroon. Mol. Ecol. 10, 1471–1488 (2001)

  13. 13.

    , & Differential gene exchange between parapatric morphs of Littorina saxatilis detected using AFLP markers. J. Evol. Biol. 14, 611–618 (2001)

  14. 14.

    Sympatric speciation in animals: the ugly duckling grows up. Trends Ecol. Evol. 16, 381–390 (2001)

  15. 15.

    Rapid origin of sexual isolation and character divergence in a cline. Evolution 36, 213–223 (1982)

  16. 16.

    Sympatric speciation via habitat specialization driven by deleterious mutations. Evolution 51, 1751–1763 (1997)

  17. 17.

    & Interactions among quantitative traits in the course of sympatric speciation. Nature 400, 351–354 (1999)

  18. 18.

    & On the origin of species by sympatric speciation. Nature 400, 354–357 (1999)

  19. 19.

    , & Sexual selection at the protein level drives the extraordinary divergence of sex-related genes during sympatric speciation. Proc. R. Soc. Lond. B 268, 2155–2161 (2001)

  20. 20.

    & Sympatric speciation by sexual conflict. Proc. Natl Acad. Sci. USA 99, 10533–10538 (2002)

  21. 21.

    & Spatial niche packing, character displacement and adpative speciation in an environmental gradient. Evol. Ecol. Res. (in the press)

  22. 22.

    , & Theory and speciation. Trends Ecol. Evol. 16, 330–343 (2001)

  23. 23.

    , , & Evolutionarily singular strategies and the adaptive growth and branching of the evolutionary tree. Evol. Ecol. 12, 35–57 (1998)

  24. 24.

    & Evolutionary branching and sympatric speciation caused by different types of ecological interactions. Am. Nat. 156, S77–S101 (2000)

  25. 25.

    Evolutionary branching under asymmetric competition. J. Theor. Biol. 197, 149–162 (1999)

  26. 26.

    & Interspecific competition, environmental gradients, gene flow, and the coevolution of species' borders. Am. Nat. 155, 583–605 (2000)

  27. 27.

    Spatial patterns in the distribution of polygenic characters. J. Theor. Biol. 70, 213–228 (1978)

  28. 28.

    Clines in polygenic traits. Genet. Res. 74, 223–236 (1999)

  29. 29.

    & Detecting the geographical pattern of speciation from species-level phylogenies. Am. Nat. 155, 419–434 (2000)

  30. 30.

    , & The Geometry of Ecological Interactions: Simplifying Spatial Complexity (Cambridge Univ. Press, Cambridge, UK, 2000)

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Acknowledgements

We thank H. Metz, D. Tautz, G. Meszéna, D. Schluter, E. Knox, O. Leimar, M. Kirkpatrick and T. Barraclough for discussions and comments. The order of authors is reverse alphabetical.

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Affiliations

  1. *Departments of Zoology and Mathematics, University of British Columbia, Vancouver, Canada V6T 1Z4

    • Michael Doebeli
  2. †Adaptive Dynamics Network, International Institute for Applied Systems Analysis, A-2361 Laxenburg, Austria

    • Ulf Dieckmann

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The authors declare that they have no competing financial interests.

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Correspondence to Michael Doebeli.

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https://doi.org/10.1038/nature01274

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