Phylogenetics of Lysipomia (Campanulaceae): Evolution in a Paramo Endemic

对安第斯高山苔原植物的系统发育研究为研究热带高海拔环境的进化过程提供了一个独特的机会。北亚利桑那大学的蒂娜·艾尔斯博士正在研究Lysipomia属，这是一种中型的小型“缓冲”植物，大约有28种，仅限于南美洲安第斯山脉苔原般的群落。Lysipomia最丰富的物种分布在厄瓜多尔和秘鲁，位于安第斯山脉北部一个主要地质断裂的两侧，被称为Piura分水岭或万卡班巴凹陷。广泛分布物种的明显缺失和大萧条附近大量狭窄范围特有物种的存在，证明了这一屏障和相关的气候变化在Lysipomia系统发育中发挥了重要的进化作用。本研究的主要重点是利用形态学、解剖学、染色体和DNA的信息，并基于植物标本馆资料和最近的野外收集，构建一个Lysipomia物种的系统发育。由于形态特征可能在这些恶劣环境中表现出收敛性，因此将强调由叶绿体（限制性内切酶定位）和核（核糖体ITS序列）DNA生成的独立数据集。其他种类的桔黄科植物在叶绿体染色体上显示出主要的基因重排，如果在Lysipomia中遇到这种重排，我们将特别努力来绘制这种重排。物种级别的系统发育将允许对安第斯高山栖息地的物种形成模式和适应性辐射进行测试，并将有助于重建高海拔热带群落的历史生物地理。

9527866 Ayers Phylogenetic studies of plants of the Andean alpine tundra provide a unique opportunity to investigate evolutionary processes in tropical, high-elevation environments. Dr. Tina Ayers of Northern Arizona University is studying the genus Lysipomia, a medium-sized group of ca. 28 species of small "cushion" plants restricted to tundra-like communities in Andean South America. The greatest species diversity in Lysipomia is found in Ecuador and Peru on both sides of a major geologic break in the northern Andes known as the Piura Divide or the Huancabamba Depression. The apparent absence of widespread species and the presence of a large number of narrow ranging endemic species adjacent to the Depression argues for the idea that this barrier and associated climatic changes have played an important evolutionary role in Lysipomia phylogeny. The primary focus of the study is to construct a phylogeny of the species of Lysipomia using information from morphology, anatomy, chromosomes, and DNA, and based upon herbarium material and recent field collections. Because morphological features may show convergence in these harsh environments, independent data sets generated from both chloroplast (restriction enzyme mapping) and nuclear (ribosomal ITS sequences) DNA will be emphasized. Other groups of Campanulaceae show major rearrangements in gene order on the chloroplast chromosome, and special efforts will be made to map such rearrangements, if encountered, in Lysipomia. A species-level phylogeny will allow tests of modes of speciation and adaptive radiation in Andean alpine habitats, and will help reconstruct the historical biogeography of high-elevation tropical communities.