Chloroplast DNA Phylogeny of Seed Plants and Basal Angiosperms

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DEB-0090313Richard G. Olmstead Dr. Richard Olmstead at the University of Washington has been given an award to study the systematic relationships among the major groups of living seed plants and land plants. The proposed research addresses the question of the early diversification of plants following their adaptation to life on land by comparing carefully chosen gene sequences selected for their slow evolutionary rate, which makes them well-suited to study ancient plant diversification. Determining the pattern of early diversification of land plants and seed plants has implications for our understanding of what the earliest land plants may have looked like and for what the course of evolution in reproductive and vegetative features may have taken. Several prior DNA-based studies examining individual genes have yielded conflicting results or have been unable to resolve relationships among the extant representatives of lineages that diverged over 200 million years ago. The experimental approach will be to determine DNA sequences for 17 chloroplast genes totaling approximately 13,000 nucleotides for each of approximately 50 plant species chosen to represent previously identified "critical" lineages of land plants. This work builds upon Dr. Olmstead's prior work on the early diversification of flowering plants. This will provide a 3-fold increase in the data pertaining to the problem and should provide a substantially improved picture of the early radiation of living land plants.