Does natural selection promote population divergence? A comparative analysis of population structure using amplified fragment length polymorphism markers and quantitative traits

Authors

  • T. Steinger,

    Corresponding author
    1. Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
    Search for more papers by this author
    • Present address: Institute of Evolutionary and Ecological Sciences, University of Leiden, Kaiserstraat 63, 2311 GP Leiden, The Netherlands.

  • P. Haldimann,

    1. Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
    Search for more papers by this author
  • K. A. Leiss,

    1. Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
    Search for more papers by this author
    • Present address: Institute of Plant Sciences, University of Bern, Altenbergrain 21, CH-3013 Bern, Switzerland.

  • H. Müller-Schärer

    1. Department of Biology, Unit of Ecology and Evolution, University of Fribourg, Chemin du Musée 10, CH-1700 Fribourg, Switzerland
    Search for more papers by this author

T. Steinger. Tel.: 41 26 300 8822; Fax: 41 26 300 9698; E-mail: Thomas.Steinger@unifr.ch

Abstract

Divergent natural selection is considered an important force in plant evolution leading to phenotypic differentiation between populations exploiting different environments. Extending an earlier greenhouse study of population differentiation in the selfing annual plant Senecio vulgaris, we estimated the degree of population divergence in several quantitative traits related to growth and life history and compared these estimates with those based on presumably neutral molecular markers (amplified fragment length polymorphisms; AFLPs). This approach allowed us to disentangle the effects of divergent selection from that of other evolutionary forces (e.g. genetic drift). Five populations were examined from each of two habitat types (ruderal and agricultural habitats). We found a high proportion of total genetic variance to be among populations, both for AFLP markers (φST = 0.49) and for quantitative traits (range of QST: 0.26–0.77). There was a strong correlation between molecular and quantitative genetic differentiation between pairs of populations (Mantel's r = 0.59). However, estimates of population differentiation in several quantitative traits exceeded the neutral expectation (estimated from AFLP data), suggesting that divergent selection contributed to phenotypic differentiation, especially between populations from ruderal and agricultural habitats. Estimates of within-population variation in AFLP markers and quantitative genetic were poorly correlated, indicating that molecular marker data may be of limited value to predict the evolutionary potential of populations of S. vulgaris.

Ancillary