Dissertation Research: Historical Biogeography and Molecular Phylogenetics of Chamaeleonidae

论文研究：变色龙科的历史生物地理学和分子系统发育学

• 批准号: 0073323
• 负责人: Allan Larson
• 金额: $ 0.98万
• 依托单位: Washington University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2000
• 资助国家: 美国
• 起止时间: 2000-07-01 至 2002-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0073323&HistoricalAwards=false
• 关键词: Dissertation; Research; Historical; Biogeography; Molecular

0073323Larson and Townsend The distribution of animal and plant species over the earth has long puzzled biologists, as it often appears that closely related species are found in geographically separated areas while intervening regions are devoid of members of the same group. With the advent of plate tectonic theory, new ideas about species distributions based on continental drift could be formulated, and these hypotheses could ideally be tested if a reliably supported phylogeny (evolutionary genealogy) of the group in question were available. With the modern tools of DNA sequencing now available to systematists, well supported phylogenies can be obtained for numerous groups of animals and plants, providing opportunities to test proposed patterns of distribution resulting from plate tectonic events. The primary goal of work by graduate student Ted Townsend, with guidance from faculty adviser Allan Larson, is to construct a phylogenetic hypothesis for the lizard family Chamaeleonidae using DNA sequence data, and then to use this phylogeny to test various biogeographic hypotheses about the group. Chamaeleons include about 130 species of easily recognizable lizards, distributed in Africa, Madagascar, and India, with a few species ranging into southernmost Europe. The first three landmasses are remnants of the southern supercontinent of Gondwana which, according to plate tectonic theory, began its breakup about 140 million years ago. A reliable phylogeny of chamaeleons would allow tests of historical patterns of migration and of lineage splitting, which has so far not been possible on the basis of morphological studies of traditional taxonomic characters. New evidence from mitochondrial gene sequences and from two potential nuclear genes will help construct a phylogenetic framework for the group, based on field collected materials from Africa and Madagascar and from samples provided by colleagues and museum holdings.

0073323拉森和汤森地球上动植物物种的分布长期以来一直困扰着生物学家，因为它经常出现在地理上分离的地区发现密切相关的物种，而中间地区缺乏同一群体的成员。随着板块构造理论的出现，基于大陆漂移的物种分布的新想法可以被制定出来，如果有可靠的支持，这些假设可以理想地进行测试。随着DNA测序的现代工具，系统学家现在可以得到很好的支持，动物和植物的许多群体的同源性，提供了机会来测试所提出的模式的分布所造成的板块构造事件。研究生泰德·汤森（Ted Townsend）在导师艾伦·拉森（Allan Larson）的指导下，主要工作目标是利用DNA序列数据构建蜥蜴科变色龙科的系统发育假说，然后利用这一系统发育来检验关于该群体的各种系统发育假说。变色龙包括大约130种容易识别的蜥蜴，分布在非洲，马达加斯加和印度，少数物种分布在欧洲最南端。前三块大陆是冈瓦纳南部超大陆的残余，根据板块构造理论，冈瓦纳大陆在大约1.4亿年前开始分裂。一个可靠的变色龙的系统发育将允许测试的历史模式的迁移和谱系分裂，这是迄今为止不可能的基础上的形态学研究的传统分类特征。来自线粒体基因序列和两个潜在的核基因的新证据将有助于构建该群体的系统发育框架，该框架基于从非洲和马达加斯加收集的材料以及同事和博物馆藏品提供的样本。