DISSERTATION RESEARCH: Evolution and Systematics of Claytonia lanceolata sensu lato (Montiaceae)

多倍化(全基因组复制)对开花植物的多样化是，而且很可能曾经是。了解开花植物中多倍体发生的方式和原因，可能会为适应与冰川、火山和全球气候变化等历史性环境变化的相互作用提供关键的见解。这项研究将有助于更好地了解轮叶沙枣物种复合体的多样性，这对有效保护和管理它们生长的栖息地至关重要。尖端的生化和计算技术现在使我们能够更好地估计进化史，并测试关于物种形成的生态、时间和地理背景的假设。这项研究将加深我们对基因通过种子和花粉的传播，物种之间的基因共享，以及染色体数量变异对植物多样性的影响的理解。更好地了解加州残留的高山群落将是另一项重要的贡献。科学交流、公众宣传和指导本科生也是该项目不可或缺的一部分。多倍体可能导致物种复合体，是物种多样化的基本过程之一，多倍体是全球植物群落的重要元素。初步研究表明，轮叶蜡梅属物种复合体(Montiaceae)是非单系的，由许多多倍体谱系组成，分布在北美西部山区各种独特的空间和生态条件下。该项目涉及杉木物种复合体及其近亲的生物地理学、染色体进化、生态位多样性和系统发育的研究。该项目调查了(1)野外非生物和生物栖息地特征，以更好地了解生殖隔离的机制；(2)种群内和种群之间的染色体数量，利用流式细胞仪和染色体计数方法来表征潜在的适应性变异；(3)利用形态计量学来更好地发展关于选择作用于叶片和地下茎解剖和形态的假设；(4)利用下一代测序(RADseq)来了解共域种群中种间基因流动的模式，以了解物种被生殖隔离的程度。这项研究将导致我们对物种边界及其在杉木复合体中的分布的认识的重大修订，以及对几个新的分类群的描述。

Polyploidization (whole genome duplication) is, and likely was, instrumental in the diversification of flowering plants. Understanding how and why polyploidy occurs in flowering plants may provide critical insight into the interplay of adaptation and historic environmental changes like glaciation, volcanism, and global climate change. This research will provide an improved understanding of diversification in the Claytonia lanceolata species complex, which is critical for effective conservation and management of the habitats in which they grow. Cutting edge biochemical and computational techniques now allow us to better estimate evolutionary histories, and test hypotheses concerning the ecological, temporal, and geographic context of speciation. This research will increase our understanding of gene dispersal via seeds and pollen, gene sharing among species, and the influence of chromosome number variation on plant diversification. A better understanding of relict alpine communities in California will be an additional, important contribution. Scientific communication, public outreach and mentoring undergraduate students are integral parts of the project as well.Polyploidy, potentially giving rise to species complexes, represents one of the fundamental processes in diversification and polyploids are important elements of plant communities across the globe. Preliminary study indicates that the Claytonia lanceolata species complex (Montiaceae), as currently circumscribed, is non-monophyletic and consists of many polyploid lineages inhabiting a variety of unique spatial and ecological conditions in the mountains of western North America. This project involves research into biogeography, chromosome evolution, niche diversification, and phylogeny of the C. lanceolata species complex and close relatives. The project investigates (1) abiotic and biotic habitat characteristics in the field to better understand mechanisms responsible for reproductive isolation, (2) chromosome number within and among populations using flow cytometry and chromosome counting methods to characterize potentially adaptive variation, (3) variation in vegetative characters using morphometrics to better develop hypotheses concerning selection acting on leaf and subterranean stem anatomy and morphology, and (4) patterns of inter-specific gene flow in sympatric populations using Next Generation Sequencing (RADseq) to understand the extent to which species are reproductively isolated. This research will result in a significant revision of our knowledge of species boundaries and their distributions in the C. lanceolata complex, in addition to the description of several taxa new to science.