Dissertation Research: Turning Vines Into Trees: A Genome Skimming Approach to the Phylogenetics of New World Milkweed VInes (Matelea, subg. Chthamalia, Apocynaceae)

虽然植物对干旱的适应已经在几个类群中得到了很好的研究，例如仙人掌，但对沙漠和其他旱地中大多数植物的多样性知之甚少。一群乳草(Matelea subg.)Chthamalia)生活在墨西哥和美国西南部的干燥或季节性干燥的生境中，为研究干旱生物区域的适应性多样化提供了一个有用的系统。这一群是一个大型的、主要是热带的乳草藤本植物支系的一部分，大多数都表现出对干旱的明显适应。许多已经失去了缠绕的能力(茎平展在地上)，开出了钟形的小花，或者被大量的毛发覆盖。这项研究将使用现有最强大的技术来重建Chthamalia的进化史，并分析对干旱的适应进化。采用基因组略读的新一代DNA测序该项目将用于获得完整的叶绿体基因组、部分线粒体基因组和完整的核糖体基因序列，以有力地估计系统发育关系，这将作为形态适应进化分析的框架。该项目将解决分类学上有争议的鲜为人知的植物的分类问题。Chthamalia的几个物种极其稀有；解决分类学问题并更多地了解它们的进化将有助于未来物种和栖息地的保护工作。将传统的系统方法与新的分子方法相结合，对于解决有关进化、适应和物种形成的假说至关重要。研究生和本科生将获得实验室和生物信息学培训，并有机会在全国会议上展示研究成果。

Although plant adaptations to aridity have been well studied in a few groups, such as cacti, relatively little is known about the diversification of most plants in deserts and other drylands. A group of milkweeds (Matelea subg. Chthamalia) inhabits dry or seasonally dry habitats in Mexico and the southwestern United States, providing a useful system for investigating adaptive diversification in arid bioregions. This group is part of a large, mostly tropical clade of milkweed vines (Gonolobinae) and most exhibit apparent adaptations to aridity. Many have lost their ability to twine (with stems spreading flat on the ground), have small, bell-shaped flowers, or are covered by an abundance of hairs. This research will use the most powerful available techniques to reconstruct the evolutionary history of Chthamalia and to analyze the evolution of adaptations to aridity. Next generation DNA sequencing employing a ?genome skimming? approach will be used to obtain complete chloroplast genomes, partial mitochondrial genomes, and complete nuclear ribosomal gene sequences to robustly estimate phylogenetic relationships, which will serve as a framework for evolutionary analyses of morphological adaptations.This project will resolve the classification of little-known plants that have been taxonomically controversial. Several species of Chthamalia are exceedingly rare; resolving taxonomic questions and greater knowledge of their evolution will contribute to future conservation efforts of species and habitats. Integration of traditional systematic approaches with new molecular methods is critical to address hypotheses about evolution, adaptation, and speciation. Graduate and undergraduate students will gain laboratory and bioinformatic training as well as the opportunity to present research results at national meetings.