DISSERTATION RESEARCH: Investigating the main contributors to plant speciation in a rapidly diverging lineage in western North America

物种形成过程的研究，或一个物种分裂成两个，最经常采取的方法是深入研究单个物种或物种对，因此集中在一个事件的分歧的主要驱动力。相反，如果我们从更长的时间、进化的角度来看待物种形成，通过进化关系的透镜和对识别和定义物种很重要的特征来审视，我们就有机会在最近的物种形成事件的水平上，并通过群体的进化历史来研究物种属性的相对贡献。这意味着我们可以自信地识别和描述物种。分子、形态、生态和/或地理变异通常作为一个物种与另一个物种之间界限的证据，然而，当单独使用时，这些特征并不总是能够区分物种。这项研究将有助于物种界定的理论和方法的实证检验，并将弥合理论，实证和应用科学之间的差距。通过努力实现反映其进化历史的物种定义，该项目将有助于发现，保护和管理北美西部的生物多样性。最后，这项研究将直接影响培训和学术发展的合作PI通过新的实验室，现场和分析技术的学习，以及指导和本科生的培训。该项目旨在通过确定物种标准，物种的稳健划界，以及评估单个物种标准在物种发生中的贡献来确定物种形成的宏观进化特征，从而开始构建北美西部山区物种形成的广阔图景。为了实现这一目标，该项目需要1）收集广泛的物种标准数据（即，分子，形态，生态，地理和细胞学数据，2）严格的物种划界方法（使用多个个体标准和综合数据方法）的应用，重点是在一个属的广泛的系统发育中解决不好的节点，和3）通过比较系统发育分析的性状进化的速度，随着时间的推移，个别物种标准的相对贡献的检查。北美西部的几个物种复合体的画笔（Castilleja，列当科）的不同的多年生分支的模式系统接近这些问题，并选择了他们的对比变化的形态，生态和细胞学特征。

Studies of the process of speciation, or the splitting of one species into two, have most often taken the approach of intensive study of a single species or species pair, and have therefore focused on the primary driver of divergence of that one event. If instead, we take a longer-time, evolutionary view of speciation, examined through the lens of evolutionary relationships and the traits that are important for recognizing and defining species, we have the opportunity to investigate the relative contributions of the properties of a species at both the level of recent speciation events and back through the evolutionary history of the group. This implies that we can confidently identify and describe species. Molecular, morphological, ecological, and/or geographic variation often serve as evidence of boundaries between one species and another, however, when used alone, these characteristics are not always capable of differentiating species. This study will contribute significantly to empirical tests of the theory and methodologies of species delimitation, and will bridge the gap between theoretical, empirical, and applied sciences. By working towards definitions of species that reflect their evolutionary histories, this project will contribute to the discovery, conservation, and management of biodiversity in western North America. Finally, this research will directly impact the training and academic development of the co-PI through the learning of new laboratory, field, and analytical techniques, as well as the mentoring and training of undergraduates. This project aims to identify the macroevolutionary signatures of speciation via the identification of species criteria, the robust delimitation of species, and the evaluation of the contribution of individual species criteria across a phylogeny, to begin to construct a broad picture of speciation in the mountains of western North America. To accomplish this objective, this project entails 1) the collection of extensive species criterion data (i.e., molecular, morphological, ecological, geographic, and cytological data, 2) the application of rigorous species delimitation methods (using multiple individual criteria and an integrated data approach) focused on poorly resolved nodes in a genus-wide phylogeny, and 3) the examination of the relative contributions of individual species criteria through comparative phylogenetic analyses of the rate of trait evolution through time. Several western North American species complexes from the diverse perennial clade of the paintbrushes (Castilleja, Orobanchaceae) are the model system for approaching these questions, and were selected for their contrasting variation in morphological, ecological, and cytological characteristics.