Phylogenetic Study of Homosporous Ferns Based on Chloroplast and Nuclear Gene Sequences and Morphology

基于叶绿体和核基因序列及形态学的同孢蕨类植物系统发育研究

• 批准号: 9307068
• 负责人: Gerald Gastony
• 金额: $ 18.5万
• 依托单位: Indiana University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-10-15 至 1998-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9307068&HistoricalAwards=false
• 关键词: Phylogenetic; Study; Homosporous; Ferns; Based

9307068 Gastony Difficulties in identifying natural evolutionary lineages in homosporous ferns and in circumscribing these lineages as genera and families are often attributed to the effects of convergent and parallel evolution on the morphological characters traditionally used in fern taxonomy. The cheilanthoid ferns, largely adapted to semi desert conditions or to other seasonally dry habitats, are the foremost examples of this. Molecular data from the chloroplast genome are unaffected by habitat related selective forces acting on morphology and are beginning to yield fundamental insights into fern evolution and phylogeny. However, recent studies on flowering plants have found some instances in which hybridization, introgression, or lineage sorting may lead to significant error in phylogenetic reconstructions based solely on the cytoplasmically inherited chloroplast genome. This raises concern for ferns because the high incidence of allopolyploid hybrids and high basic chromosome numbers in ferns suggest that modern ferns may be paleopolyploids in whose ancestry reticulate evolution has been important. Dr. Gastony's project will serve as a model study for homosporous ferns by using cladistically analyzed molecular data from chloroplast DNA (nucleotide sequences of the rbc L gene) to provide fundamental new insights into cheilanthoid fern relationships and phylogeny. Importantly also, the project will use molecular data f rom the nuclear genome (nucleotide sequences of ribosomal DNA) to compare with chloroplast DNA results and with traditional morphological characters. %%% The combined morphological and molecular data will form the basis of a revised classification of cheilanthoid ferns and of a robust reconstruction of their phylogenetic relationships, on a worldwide basis.

小行星9307068 同孢蕨类植物的自然进化谱系的鉴定和将这些谱系划分为属和科的困难通常归因于传统蕨类植物分类学中使用的形态特征的趋同和平行进化的影响。 唇花蕨，主要适应半沙漠条件或其他季节性干燥的栖息地，是最重要的例子。 叶绿体基因组的分子数据是不受栖息地相关的选择力作用于形态，并开始产生根本的见解蕨类植物的进化和发育。 然而，最近对显花植物的研究发现，在一些情况下，杂交，渐渗，或谱系分选可能会导致显着错误的系统发育重建的基础上，细胞质遗传的叶绿体基因组。 这引起了人们对蕨类植物的关注，因为蕨类植物中异源多倍体杂交的高发生率和高基本染色体数表明现代蕨类植物可能是古多倍体，其祖先的网状进化很重要。 Gastony博士的项目将通过使用叶绿体DNA的分支分析分子数据（叶绿体DNA的核苷酸序列）作为同型孢子蕨类植物的模型研究。 RBC L基因），为研究唇花蕨的亲缘关系和亲缘关系提供了新的基础。 同样重要的是，该项目将使用来自核基因组的分子数据（核糖体DNA的核苷酸序列）与叶绿体DNA结果和传统的形态特征进行比较。%%% 结合形态和分子数据将形成的基础上修订的cheilanthoid蕨类植物的分类和强大的重建其系统发育关系，在世界范围内。