Collaborative Research: Exploring the Evolution of an Extreme Makeover in Ferns

“银毛蕨类植物”(属于铁线蕨属)是一种典型的蕨类植物--解剖精美，陆生的，喜欢遮荫。“鞋状蕨类植物”(属于一个被称为类维生素的类群)是非常不同的：高度简化的、居住在树冠上的附生植物，具有重复的基因组，表现出加速的分子进化速度。令人惊讶的是，铁线藻类和类维生素是密切相关的，组成了生命树的一个单一分支--一个血统显然见证了极端的形态、生态和基因组的改变。这项拟议的研究旨在首先通过对DNA序列数据的分析来建立这些蕨类植物的强大系统发育。随后的分析可以揭示蕨类植物从银线到鞋带的进化历史，通过更好地刻画蕨类植物这种极端转变的进化历史，本研究将更好地阐明形态简化、生态过渡、基因组复制和分子进化速度加快的进化过程。由于所有这些过程都经常在生命之树上遇到，但人们对此知之甚少，因此，在这里努力揭示和描述它们之间的联系具有广泛的相关性。该项目包括一个多学科的培训计划，以促进学习、教学和发现，并直接针对对植物系统学、分子进化和系统发育领域感兴趣的本科生和研究生。该项目还将追求重大的科学教育和推广目标。

The "maidenhair ferns" (belonging to the genus Adiantum) are quintessential ferns -- beautifully dissected, terrestrial, and shade-loving. The "shoe-string ferns" (belonging to a group known as vittarioids) are extremely different: highly simplified, canopy-dwelling epiphytes, with duplicated genomes that exhibit accelerated rates of molecular evolution. Surprisingly, Adiantum and the vittarioids are closely related, comprising a single branch of the tree of life -- a lineage that evidently witnessed an extreme morphological, ecological, and genomic makeover. The proposed research aims to first establish a robust phylogeny for these ferns through analyses of DNA sequence data. Subsequent analyses can then reveal the evolutionary history of the "maidenhair" to "shoestring" fern transformation.By better characterizing the evolutionary history of this extreme makeover in ferns, this study will better elucidate the evolutionary processes of morphological simplification, ecological transition, genome duplication, and molecular evolutionary rate acceleration. Because all of these processes are frequently encountered across the tree of life, but poorly understood, efforts here to uncover and characterize links among them are broadly relevant. This project encompasses a multidisciplinary training program to promote learning, teaching, and discovery, and is squarely aimed at undergraduate and graduate students interested in the areas of plant systematics, molecular evolution, and phylogenetics. The project will also pursue significant science education and outreach goals.