Dissertation Research: Evolution and Systematics of a Widespread Polyploid Fern Complex, Dryopteris filix-mas

论文研究：广泛分布的多倍体蕨类复合体的进化和系统学，鳞毛蕨

• 批准号: 9701318
• 负责人: Charles Werth
• 金额: $ 1万
• 依托单位: Texas Tech 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: 1997-07-01 至 1999-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9701318&HistoricalAwards=false
• 关键词: Dissertation; Research; Evolution; Systematics; Widespread

9701318 Werth Graduate student Lilin Xiang, under the direction of Prof. Charles Werth at Texas Tech University, is studying the origin and diversification of the so-called male fern, Dryopteris filix-mas, over its wide northern-hemisphere distributional range. A polyploid plant, the male fern is thought to combine sets of chromosomes from two or possibly more parental diploid fern species that hybridized to produce doubled-chromosome offspring. Suspected diploid parents are Eurasian Dryopteris species, but American and Chinese taxa will also be studied. One goal is to distinguish between a single origin followed by dispersal, or multiple origins over the range of distribution, possibly from different parental species on the different continents. New evidence from molecular biology will help solve the problem, including electrophoretic analysis of protein variation (an indirect measure of genetic variability, sampling mostly nuclear genes) and direct DNA sequencing of a chloroplast gene. Population samples from North America, Europe, Turkey, and China are being gathered to provide extensive coverage of the morphological diversity known in this group of ferns. Polyploidy, or multiple sets of chromosomes (which sometimes restores fertility to otherwise sterile plant hybrids), is widespread in land plants, especially in ferns. As in the male fern, Dryopteris filix-mas, it is often associated with a widespread, almost weedy distribution, accompanied by minor morphological variation. Whether the polyploid arose once and dispersed widely to its present range, or arose through repeated hybridization events in various parts of the current distribution, is a question difficult to answer with only traditional taxonomic characters of morphology and anatomy. New molecular evidence from allozyme analyses and DNA sequencing, drawn from extensive population samples across the range and including several putative parent taxa, will help resolve the matter. In turn, the Dryopteris case will add to the small number of rigorous studies that analyze the historical biogeography of polyploid plant taxa.

9701318 WERTH研究生Lilin Xiang在德克萨斯理工大学的Charles Werth教授的指导下，正在研究所谓的男性蕨类植物Dryopteris Filix-Mas的起源和多样化，其北部北部 - 透明范围广泛。雄性蕨类植物被认为是从两个或可能是更多父母二倍体蕨类物种的染色体组合，它们杂交产生了两倍的染色体后代。怀疑的二倍体父母是欧亚植物的物种，但也将研究美国和中国分类单元。一个目标是区分单个起源，然后区分分布范围内的多个起源，可能是从不同大陆的不同父母物种中分布。分子生物学的新证据将有助于解决该问题，包括蛋白质变异的电泳分析（遗传变异性的间接度量，主要是核基因采样）和叶绿体基因的直接DNA测序。来自北美，欧洲，土耳其和中国的人口样本正在收集，以广泛覆盖这一蕨类植物中已知的形态多样性。 多倍体或多组染色体（有时会恢复无菌植物杂种的生育能力），在陆地植物中广泛存在，尤其是在蕨类植物中。与雄性蕨类植物，干pterix filix-mas一样，它通常与广泛的，几乎是杂草分布有关，并伴随着较小的形态变化。多倍体是出现一次并广泛地分散到当前范围内，还是通过当前分布的各个部分的重复杂交事件而产生，这是一个很难回答的问题，只有传统的形态学和解剖学特征。来自同种酶分析和DNA测序的新分子证据，由整个范围内的广泛人口样本和包括几个假定的父型分类单元得出，将有助于解决此问题。反过来，干pteris情况将增加少量的严格研究，这些研究分析了多倍体植物分类群的历史生物地理学。