Gene flow and simulation of transgene dispersal from hybrid poplar plantations

Authors

  • Stephen P. DiFazio,

    1. Department of Biology, West Virginia University, Morgantown, WV 26506-6057, USA
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  • Stefano Leonardi,

    1. Dipartimento di Scienze Ambientali, Università di Parma, 43100 Parma, Italy
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  • Gancho T. Slavov,

    1. Department of Biology, West Virginia University, Morgantown, WV 26506-6057, USA
    2. Department of Dendrology, University of Forestry, Sofia 1756, Bulgaria
    3. Institute of Biological, Environmental and Rural Sciences, Aberystwyth University, Aberystwyth SY23 3EB, UK
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  • Steven L. Garman,

    1. National Park Service, PO Box 848, Moab, UT 84532, USA
    2. Department of Forest Ecosystems and Society, Oregon State University, 3180 SW Jefferson Way, Corvallis, OR 97331, USA
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  • W. Thomas Adams,

    1. Department of Forest Ecosystems and Society, Oregon State University, 3180 SW Jefferson Way, Corvallis, OR 97331, USA
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  • Steven H. Strauss

    1. Department of Forest Ecosystems and Society, Oregon State University, 3180 SW Jefferson Way, Corvallis, OR 97331, USA
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Author for correspondence:
Steven H. Strauss
Tel: +1 541 737 6578
Email: steve.strauss@oregonstate.edu

Summary

  • Gene flow is a primary determinant of potential ecological impacts of transgenic trees. However, gene flow is a complex process that must be assessed in the context of realistic genetic, management, and environmental conditions.
  • We measured gene flow from hybrid poplar plantations using morphological and genetic markers, and developed a spatially explicit landscape model to simulate pollination, dispersal, establishment, and mortality in the context of historical and projected disturbance and land-use regimes.
  • Most pollination and seed establishment occurred within 450 m of the source, with a very long tail. Modeled transgene flow was highly context-dependent, strongly influenced by the competitive effects of transgenes, transgenic fertility, plantation rotation length, disturbance regime, and spatial and temporal variation in selection. The use of linked infertility genes even if imperfect, substantially reduced transgene flow in a wide range of modeled scenarios. The significance of seed and vegetative dispersal was highly dependent on plantation size.
  • Our empirical and modeling studies suggest that transgene spread can be spatially extensive. However, the amount of spread is highly dependent on ecological and management context, and can be greatly limited or prevented by management or mitigation genes such as those that cause sexual infertility.

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