MtDNA and CpDNA Sequence Variation in Limber Pine and Ponderosa Pine

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Mitton9983151Evolutionary and conservation biologists study the geographic variation within a species with a new technique, a phylogeographic analysis, or a phylogeography. This technique combines estimates of genetic distances among populations with their geographic positions to better understand the historical relationships among the populations. Phylogeographic studies are commonly used in studies of animals, but rarely in plants. The low mutation rate of plant mitochondrial DNA minimizes the sequence variation needed for a phylogeography. The proposed research is a survey for sufficient mitochondrial and chloroplast DNA sequence variation to conduct phylogeographies of limber pine and ponderosa pine.Conifers present an exciting opportunity for phylogeographic studies, for their mitochondria and chloroplasts have different patterns of inheritance and, consequently, drastically different potentials for dispersal. In the pines, the maternally inherited mtDNA has very low potential for dispersal, while the paternally inherited cpDNA has high potential for dispersal. The disparate potentials for gene flow are expected to produce dramatically different phylogeographies. The mitochondrial phylogeography should provide an indication of ancient historical events, such as isolation in glacial refugia. The chloroplast phylogeography should provide insights into the magnitude of pollen flow among populations today and in the recent past.