Chloroplast DNA Phylogeny of Seed Plants and Basal Angiosperms

DEB-0090313理查德G.华盛顿大学的理查德·奥姆斯特德博士因研究活种子植物和陆生植物的主要类群之间的系统关系而获奖。 拟议的研究解决了植物适应陆地生活后早期多样化的问题，方法是比较精心挑选的基因序列，这些基因序列因其缓慢的进化速度而被选中，这使得它们非常适合研究古代植物多样化。 确定陆地植物和种子植物早期多样化的模式，对我们理解最早的陆地植物可能是什么样子以及生殖和营养特征的进化过程可能有影响。 先前的几项基于DNA的研究检查了单个基因，得出了相互矛盾的结果，或者无法解决两亿多年前分化的血统的现存代表之间的关系。 实验方法将是确定17个叶绿体基因的DNA序列，总计约13,000个核苷酸的约50种植物物种中的每一个选择代表以前确定的陆地植物的“关键”谱系。 这项工作建立在Olmstead博士先前关于开花植物早期多样化的工作基础上。 这将使与该问题有关的数据增加3倍，并应提供有关活的陆地植物早期辐射的大幅改善的图片。

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.