Dissertation Research: Evolution in Linanthus and Leptodactylon (Polemoniaceae): Phylogenetic Relationships and Speciation Processes

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9411538 Soltis Graduate student Joanna Schultz, under the supervision of faculty adviser Pamela Soltis at Washington State University, is studying two related genera in the phlox family Polemoniaceae, Leptodactylon and Linanthus. The two present opportunities to contrast alternative processes of speciation in plants, either sympatric/parapatric through polyploidy (whether following hybridization or not) and allopatric, usually through dispersal and isolation of small peripheral populations. Morphological and molecular evidence, the latter including extensive data from chloroplast DNA and from protein isozymes, will be acquired to infer phylogenetic relationships among species and to assess likely routes of origin by analyzing patterns of genetic variation in closely related species. Robust phylogenetic analysis of closely related species, based on combined morphological and molecular evidence, provides the strongest test cases for assessing the relative importance of contrasting mechanisms of plant speciation, whether through polyploid evolution (usually involving hybridization of sympatric congeners) or through geographic speciation (allopatric divergence).