Jorgensen, Stacy , Barrington, David .
New insights into the heritage of Pacific Northwestern polyploids in the genus Polystichum (Dryopteridaceae).
Allopolyploids incorporate genomes from different progenitors, usually different species; they often arise via a hybridization event followed by restoration of fertility through chromosome doubling. Allopolyploidy as a mechanism of speciation is rampant in the ferns: polyploids comprise as much as 44% of the genus Polystichum. Three polyploid polystichums are found in the forests of the Pacific Northwest. The tetraploid P. braunii is twice-pinnate and is circumboreally distributed in wet forests. The tetraploid P.andersonii is once-pinnate-pinnatifid with a bulbil on the rachis, and isf ound in lowland to midmontane wet forests of northwestern North America. The hexaploid P. setigerum is once-pinnate-pinnatifid and is restricted to very wet lowland forests of coastal Alaska and British Columbia. We used direct and cloned sequences from the single-copy nuclear gene gapCp to characterize the genomes of these three polyploids. We retrieved two sequences from P. braunii: one allied to East Asian taxa and the other without near allies in our sample. Polystichum setigerum shares the two sequences retrieved from P. braunii plus a third sequence closely resembling the diploid P. munitum, in concert with the established ideas about its progenitor species. We retrieved two genomes from P. andersonii: one with a loose affinity to East Asian taxa and a second without a near ally in our sample of Asian, North American, and Australasian polystichums. Neither of the sequences show an affinity for the variant isolated from P.munitum, usually proposed as a progenitor of P. andersonii.
Log in to add this item to your schedule
1 - University of Vermont, Plant Biology, Jeffords Hall, 63 Carrigan Drive, Burlington, VT, 05405, USA
Presentation Type: Oral Paper:Papers for Sections
Location: Union E/Hyatt
Date: Monday, July 9th, 2012
Time: 2:30 PM