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Abstract Detail



Molecular Ecology and Evolution

Grady, Ben [1], Sytsma, Kenneth [2].

Spanning the soil spectrum: Evolution and ecological divergence in Eriogonum (Polygonaceae).

We examine evolutionary patterns of life history and edaphic endemism in the morphologically and ecologically diverse genus Eriogonum (Polygonaceae) by employing comparative phylogenetic methods. DNA sequence data were generated and analyzed from the chloroplast (trnL-trnF, trnD-trnT, rps16) and nuclear sources (LEAFY, nrITS) to infer broad-scale relationships within the genus, as well as relationships within a clade of both narrowly endemic and wide-ranging ‘capitate’ species of Eriogonum. Based on maximum parsimony (MP) and maximum likelihood (ML) reconstructions in our broadly sampled phylogeny, the ancestral state of Eriogonum and allied genera was likely an annual. A shift to perenniality occurred early in the evolution of Eriogonum, with multiple subsequent reversions to annual life history. To test the model of edaphic endemism in the ‘capitate’ subclade we collected and classified soil samples by a multivariate cluster analysis of nine measured physical and chemical soil properties, recognizing distinct edaphic groups. The BayesTraits ML reconstructions of edaphic groups across the plastid and nuclear trees show uncertainty at many nodes, especially the deeper nodes. Some clustering of edaphic groups is evident in terminal clades, however most species occurring in defined edaphic groups showed little clade-specific clustering. Based upon these findings, we propose a ‘generalist model’ of edaphic endemism for the ‘capitate’ subclade of Eriogonum species, with potential shifts to more specialized soil types occurring in distinct lineages. It is likely that species in this lineage of Eriogonum can tolerate a variety of azonal substrates associated with sparsely vegetated areas.

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1 - University of Wisconsin-Platteville, Biology Dept, 1 University Plaza, 235 Gardner Hall, Platteville, WI, 53818, USA
2 - University of Wisconsin, Department of Botany, Birge Hall, 430 Lincoln Drive, Madison, WI, 53706, USA

Keywords:
edaphic endemism
Eriogonum
generalist model
life history.

Presentation Type: Oral Paper:Papers for Topics
Session: 46
Location: Newberry/Riverside Hilton
Date: Wednesday, July 31st, 2013
Time: 3:45 PM
Number: 46009
Abstract ID:908
Candidate for Awards:Margaret Menzel Award


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