Dissertation Research: Molecular Phylogenetics and Interfamilial Relationships in the Portulacaceous Alliance of the Order Caryophyllales

论文研究：石竹目马齿苋属联盟的分子系统发育和科间关系

• 批准号: 9701125
• 负责人: Robert Wallace
• 金额: $ 1万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1997
• 资助国家: 美国
• 起止时间: 1997-08-15 至 2000-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9701125&HistoricalAwards=false
• 关键词: Dissertation; Research; Molecular; Phylogenetics; Interfamilial

9701125 Wallace Graduate student Wendy Applequist, under the guidance of Dr. Robert Wallace at Iowa State University, is studying the phylogenetic or genealogical relationships of plants in the four caryophyllalean families of Basellaceae, Cactaceae, Didiereaceae, and Portulacaceae, making use of botanical garden materials and field collections amassed over the years at Iowa State. The morphological features of flowers and fruits used traditionally in the classification of these plants, especially the c. 500 species of purslanes (Portulacaceae), are suspected to be unreliable in marking evolutionary groups, perhaps due to repeated, convergent adaptations in arid or desert habitats. New evidence from DNA sequences of the chloroplast genome is being sought to provide a large number of variable yet informative characters (mutations or nucleotide substitutions) that can be used to measure genetic divergences among these plants. In turn, a reliable phylogenetic framework for these plants will enable the study of their historical biogeography and patterns of adaptation to various desert regions of the world. The plants traditionally treated in the four caryophyllalean families listed above present interesting problems of evolution, biogeography, and adaptation, mostly in arid or desert habitats of the world, and primarily on the southern continents of South America, Africa, and Australia. Disentangling patterns caused by ancient continental drift from more recent dispersals and migrations has been impossible without a reliable phylogeny for the group, based on genetic features not directly affected by habitat conditions. This project is a focused effort to construct a phylogenetic framework for these plants from DNA sequence information, augmented by the morphological, chromosomal, and anatomical data in hand.

9701125华莱士大学研究生温迪·阿普奎斯特在爱荷华州立大学罗伯特·华莱士博士的指导下，利用爱荷华州立大学多年来积累的植物园材料和野外收集的资料，研究了罗汉果科、仙人掌科、迪迪亚科和马齿苋科四个石竹科植物的系统发育或系谱关系。传统上用于这些植物分类的花和果实的形态特征，特别是约500种马齿苋(马齿苋)，在标记进化类群方面被怀疑是不可靠的，可能是由于在干旱或沙漠生境中重复的、收敛的适应。人们正在从叶绿体基因组的DNA序列中寻找新的证据，以提供大量可变但信息丰富的特征(突变或核苷酸替换)，这些特征可以用来测量这些植物之间的遗传差异。反过来，这些植物可靠的系统发育框架将使研究它们的历史生物地理和适应世界不同沙漠地区的模式成为可能。上述四个石竹科传统上处理的植物存在着有趣的进化、生物地理和适应问题，主要分布在世界的干旱或沙漠生境中，主要分布在南美洲、非洲和澳大利亚的南部大陆。如果没有可靠的系统发展史，基于不受栖息地条件直接影响的遗传特征，古代大陆漂移与最近的分散和迁徙造成的分离模式是不可能的。这个项目的重点是从DNA序列信息中构建这些植物的系统发育框架，并利用现有的形态、染色体和解剖学数据进行补充。