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Conservation Genetics

, Volume 10, Issue 4, pp 827–837 | Cite as

Divergent levels of genetic variation and ploidy among populations of the rare shrub, Grevillea repens (Proteaceae)

  • Gareth D. Holmes
  • Elizabeth A. James
  • Ary A. Hoffmann
Research Article

Abstract

Rare plant species are often restricted to small and/or isolated populations that can have reduced reproductive output and adaptive potential, resulting in an increased probability of extinction. Nevertheless, evolutionary changes might occur in such populations that increase their likelihood of persisting. In Australia, many threatened species from the ecologically important genus Grevillea (Proteaceae) are found in disjunct populations and these often display varied modes of reproduction from sexual to exclusively clonal. Here we use microsatellite markers to show that isolated populations across the entire range of G. repens have developed diverse patterns of genetic variation. The largest population has a relatively low level of genetic variation, one small population displays inbreeding, two populations show evidence of clonal reproduction and two contain both triploids and diploids. The global estimate of F ST was moderately high (0.272) suggesting limited gene flow between populations and historical isolation. These findings indicate that the genetically distinct G. repens populations exhibit very different patterns of genetic variation and we propose that the development of clonality and polyploidy in small or isolated populations may allow persistence but also reduces the effective size of the sexual population. Grevillea repens populations from its eastern and western/western central centres of distribution should be viewed as separate units for conservation management.

Keywords

Genetic diversity Gene flow Microsatellites Clonality Triploidy 

Notes

Acknowledgements

We thank the staff from Parks Victoria and DSE for collection permits and access to sites, Brian Murray and Claire Marks for assistance with cytological work, nursery staff at RBGM, and Mark Blacket, Paul Mitrovski, Phillip England and Susan Hoebee for advice during the microsatellite study. Thanks to Michael Kearney for mapping assistance, Yvonne Parsons for help during the initial project stages and Mark Blacket, Margaret Byrne and an anonymous reviewer for commenting on the manuscript. This research was funded by the Cybec Foundation, Royal Botanic Gardens Melbourne and the Centre for Environmental Stress and Adaptation Research and undertaken under DSE permits 10003055 and 05/1/09/11/06.

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Copyright information

© Springer Science+Business Media B.V. 2008

Authors and Affiliations

  • Gareth D. Holmes
    • 1
  • Elizabeth A. James
    • 2
  • Ary A. Hoffmann
    • 1
  1. 1.Centre for Environmental Stress and Adaptation Research (CESAR) Hoffmann Laboratory, Level 2, Bio21 InstituteUniversity of MelbourneParkvilleAustralia
  2. 2.Royal Botanic Gardens MelbourneSouth YarraAustralia

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