Polyploidy: Genetics, Evolution and Ecology
Barker, Michael S. , Bogonovich, Marc .
Frozen Ferns: Re-evaluating hypotheses of polyploid biogeography with GIS analyses of North American ferns.
One of the striking features of polyploid species is their geographic distribution in the northern hemisphere. Classic studies of temperate floras found that the percentage of polyploid species increased towards the arctic in many plant groups. Numerous hypotheses have been proposed to explain this geographic correlation, including enhanced post-glacial colonization by polyploids and greater cold tolerance relative to diploids. However, many of these hypotheses were developed prior to computational biogeographic tools and have not been rigorously tested. We sought to leverage recent floristic efforts and to update studies of continental polyploid biogeography using a GIS approach. We evaluated these hypotheses with ferns, which are famous for their high numbers of chromosomes and rates of polyploid speciation. Ferns are particularly useful for testing hypotheses of polyploid biogeography because they possess more or less uniform characters for traits important in polyploid establishment, such as life history and spore dispersal. Using data from the Flora of North America project, we constructed a GIS data set of all North American ferns. From the literature, we also collected chromosome numbers, ploidy level, and parental relationships where known for each species. Surprisingly, our results suggest that chromosome number and polyploidy have different distributions in North America, with temperature best explaining chromosome number and diploid richness best explaining polyploid distribution. Our research demonstrates how GIS approaches can be used to address long standing questions evolutionary biology.
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1 - Indiana University, Department of Biology, Jordan Hall, 1001 East Third Street, Bloomington, Indiana, 47405, USA
2 - Indiana University, Bloomington, Biology Department, 1001 E Third St, Jordan Hall rm 142, Bloomington, IN, 47405, USA
Presentation Type: Symposium or Colloquium Presentation
Location: Room 2/Woodward
Date: Tuesday, July 29th, 2008
Time: 2:30 PM