CAREER: Gypsum Endemics of the Chihuahuan Desert: Exploring the origins and diversification of an edaphic flora using comparative phylogenetics and phylogeography

该项目整合了一项强有力的研究计划，旨在了解局限于特殊土壤的植物的进化，同时也努力提高高中生和大学生对进化生物学核心概念的理解。只生长在不寻常土壤上的植物物种，如蛇形土壤（高浓度金属）、沼泽（低pH值）或蒸发岩（高盐度），构成了世界范围内植物生物多样性的很大一部分，但令人惊讶的是，人们对它们的进化历史知之甚少。例如，局限于这些不寻常土壤的植物谱系是否能在很长一段进化时间内持续存在？同样，这些世系是如何应对过去的气候变化的？该项目将利用一组只生长在美国和墨西哥奇瓦瓦沙漠中富含石膏的土壤中的大量但研究较少的植物来回答这些问题。通过生成和分析大型DNA序列数据集，将重建和比较奇瓦瓦沙漠12个不同石膏限制植物类群的详细进化历史。这一国际研究项目代表了首次全面了解大型土壤限制性植物物种的起源和进化多样性的努力，因此将极大地提高我们对土壤如何影响植物进化以及土壤限制性植物如何应对持续气候变化的理解。该项目还将为提高高中生和大学生的进化素养提供一个新颖而引人入胜的框架，该框架将采用高中教师研讨会、文理学院创新的本科生生物实验室活动以及对学生研究人员的广泛指导相结合。

This project integrates a vigorous research program to understand the evolution of plants restricted to unusual soils with an equally vigorous effort to improve high school and college student understanding of core concepts in evolutionary biology. Plant species that grow only on unusual soils, such as serpentine soils (high concentration of metals), bogs (low pH), or evaporites (high salinity), comprise a substantial proportion of plant biodiversity worldwide, but surprisingly little is known about their evolutionary history. For example, do plant lineages restricted to these unusual soils persist over long periods of evolutionary time? Likewise, how have such lineages responded to past climate changes? This project will answer such questions using a large but poorly studied group of plants that grow only in gypsum-rich soils within the Chihuahuan Desert of the US and Mexico. By generating and analyzing large DNA sequence data sets, the detailed evolutionary histories of 12 diverse gypsum-restricted plant groups in the Chihuahuan Desert will be reconstructed and compared. This international research program represents the first comprehensive effort to understand the origin and evolutionary diversification of a large, soil-restricted group of plant species, and consequently will vastly improve our understanding of how soils influence plant evolution and how soil-restricted plants will respond to ongoing climate change. This project will also provide a novel and engaging framework for improving evolutionary literacy in high school and college students, by employing a combination of high school teacher workshops, innovative undergraduate biology laboratory activities at a liberal arts college, and extensive mentoring of student researchers.