Sigel, Erin , Barrington, David S. .
Polyphyly of a polyploid species: a inquiry into the origin of Dryopteris campyloptera and Dryopteris dilatata (Dryopteridaceae).
The role of polyploidy has been of utmost importance in fern evolution, with up to 95% of fern species attributed to ancient or recent polyploidy events. While polyploids can be formed by several mechanisms, the hybridization and genome duplication events leading to allopolyploids allow for multiple origins of the same biological species. Such is the case among some species of the Dryopteris carthusiana complex (Dryopteridaceae). Dryopteris campyloptera is an allotetraploid of eastern North America and Dryopteris dilatata is an allotetraploid of mainland Europe and the British Isles. Based on artificial hybrid-synthesis experiments, both species are hypothesized to share the circumboreal D. expansa as one diploid progenitor and a member of the D. intermedia aggregate as a second diploid progenitor. Analysis of the chloroplast markers rps4-trnS, trnLF, and rbcL demonstrates at least two origination events resulting in the combined taxa D. campyloptera and D. dilatata. Amplified Fragment Length Polymorphisms were used to determine which populations of the allotetraploid taxa were most genetically similar to progenitor diploid populations. Based on a genetic comparison of polyploid populations to populations of their progenitors in the context of geological and ecological history since the Pleistocene, the locations for multiple, distinct origins for D. campyloptera and D. dilatata in North America and Europe are proposed.
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1 - University of Vermont, Department of Plant Biology, 120B Marsh Life Science Building, Burlington, Vermont, 05405, USA
2 - University of Vermont, Plant Biology Department, Marsh Life Sciences Bldg, 109 Carrigan Drive, Burlington, Vermont, 05405-0086, USA
Presentation Type: Oral Paper:Papers for Sections
Date: Monday, July 28th, 2008
Time: 2:30 PM