Genetic structure among and within peripheral and central populations of three endangered floodplain violets

Authors

  • R. L. ECKSTEIN,

    1. Department of Landscape Ecology and Resource Management, Interdisciplinary Research Centre, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, DE-35392 Giessen, Germany,
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  • R. A. O’NEILL,

    1. Institute for Agronomy and Plant Breeding, Division of Biometry and Population Genetics, Interdisciplinary Research Centre, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, DE-35392 Giessen, Germany,
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  • J. DANIHELKA,

    1. Institute of Botany, Academy of Sciences of the Czech Republic, Department of Ecology Brno, Po®í8í 3b, CZ-603 00 Brno, Czech Republic,
    2. Institute of Botany and Zoology, Faculty of Science, Masaryk University, CZ-611 37 Brno, Czech Republic
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  • A. OTTE,

    1. Department of Landscape Ecology and Resource Management, Interdisciplinary Research Centre, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, DE-35392 Giessen, Germany,
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  • W. KÖHLER

    1. Institute for Agronomy and Plant Breeding, Division of Biometry and Population Genetics, Interdisciplinary Research Centre, Justus-Liebig-University Giessen, Heinrich-Buff-Ring 26-32, DE-35392 Giessen, Germany,
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Lutz Eckstein. Fax: +49 641 99 37 169; E-mail: lutz.eckstein@agrar.uni-giessen.de

Abstract

Understanding the partitioning of genetic variance in peripheral and central populations may shed more light on the effects of genetic drift and gene flow on population genetic structure and, thereby, improve attempts to conserve genetic diversity. We analysed genetic structure of peripheral and central populations of three insect-pollinated violets (Viola elatior, Viola pumila, Viola stagnina) to evaluate to what extent these patterns can be explained by gene flow and genetic drift. Amplified fragment length polymorphism was used to analyse 930 individuals of 50 populations. Consistent with theoretical predictions, peripheral populations were smaller and more isolated, differentiation was stronger, and genetic diversity and gene flow lower in peripheral populations of V. pumila and V. stagnina. In V. elatior, probably historic fragmentation effects linked to its specific habitat type were superimposed on the plant geographic (peripheral-central) patterns, resulting in lower relative importance of gene flow in central populations. Genetic variation between regions (3–6%), among (30–37%) and within populations (60–64%) was significant. Peripheral populations lacked markers that were rare and localized in central populations. Loss of widespread markers in peripheral V. stagnina populations indicated genetic erosion. Autocorrelation within populations was statistically significant up to a distance of 10–20 m. Higher average genetic similarity in peripheral populations than in central ones indicated higher local gene flow, probably owing to management practices. Peripheral populations contributed significantly to genetic variation and contained unique markers, which made them valuable for the conservation of genetic diversity.

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