Dissertation Research: Biogeography and Phylogeny of Malesherbiaceae

9623496克劳福德研究生卡拉·根格勒在俄亥俄州立大学丹尼尔·克劳福德的指导下，正在研究南美草本科植物，重点是从该科所有物种获得新的dna序列数据，以推断系统发育关系。这种小科是南美洲太平洋沿海沙漠地区特有的，生活在智利北部阿塔卡马沙漠隔开的两个地区。这将为研究该地区旱地动植物的生物地理和物种形成模式提供一个起点。目前的分类学分类是基于形态特征的，其中大多数还没有对可变性和可靠性进行评估。对这些进行重新评估，并从核糖体基因测序中添加新的分子证据，将为有力地推断物种之间和相关群体之间的系统发育(系谱)关系提供数据。在秘鲁的实地工作将增加智利已有的收藏品和标本馆藏的收藏品。反过来，系统发展将为生物地理学(迁徙路线、起源中心和多样化)和物种形成模式的研究提供必要的背景。南美洲的太平洋沿岸沙漠包含各种干旱的栖息地，据推测，这些栖息地是自古新世以来随着安第斯山脉的上升和向西形成的寒冷洪堡洋流而形成的。更新世冰川作用被认为进一步影响了该地区的植物分布。为了建立植物物种随时间运动的模式，必须建立许多组的稳健的系统发育。这个项目承诺了其中的一个，对于小科的马来香科植物。***

9623496 Crawford Graduate student Karla Gengler, with direction from adviser Daniel Crawford at Ohio State University, is studying the South American plant family Malesherbiaceae, with an emphasis on obtaining new DNA sequence data from all the species in the family in order to infer phylogenetic relationships. This small family is endemic to the Pacific coastal desert region of South America, and occurs in two areas separated by the Atacama Desert in northern Chile. It will serve as a starting point for the study of biogeography and speciation patterns of aridland plants and animals of this region. The current taxonomic classification is based on morphological characters, most of which have not been evaluated for variability and reliability. Re-evaluation of these and addition of new molecular evidence from nuclear ribosomal gene sequencing will provide data for robust inferences of phylogenetic (genealogical) relationship among the species and with related groups. Field work in Peru will augment collections already made in Chile and those from herbarium holdings. In turn, the phylogeny will provide a necessary background for studies of biogeography (migration routes, centers of origin and of diversification) and of speciation patterns. %%% The Pacific coastal desert of South America contains a variety of arid habitats that are presumed to have developed since the Paleocene as the Andes mountains rose and the cold Humboldt Current formed to the west. Pleistocene glaciations are thought to have further affected plant distributions in this region. In order to establish patterns of plant species movements through time, robust phylogenies of many groups must be established. This project promises one of these, for the small family Malesher`iaceae. ***