DISSERTATION RESEARCH: Untangling the Cystopteris fragilis Complex: An Investigation of the Effects of Polyploidy on Diversification Rates

论文研究：解开脆弱囊蕨复合体：多倍体对多样化率影响的研究

• 批准号: 1110652
• 负责人: Kathleen Pryer
• 金额: $ 1.5万
• 依托单位: Duke University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-05-01 至 2015-01-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1110652&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Untangling; Cystopteris; fragilis

Arguably the most dramatic mutation possible (whole-genome duplication, or polyploidy) results in an individual with double the chromosome number of its parents. Polyploidy is a common and ongoing phenomenon in plants, where many crops, for example, are polyploid. This project aims to examine the evolutionary potential and fate of polyploid lineages in ferns¬¬a plant group where nearly all species have experienced one or more episodes of polyploidy in their evolutionary past. The globally distributed fern genus Cystopteris encompasses a complex mix of diploid and polyploid species, making it ideal for investigating the effects of polyploidy on diversification rates. Using DNA sequence data from 200 Cystopteris individuals, each of known ploidy level, evolutionary relationships will be inferred, ancestral ploidy levels will be reconstructed, and speciation and extinction rates will be estimated through time. Despite its ubiquity and scientific importance, the long-term potential and evolutionary dynamics of polyploidy remain contentious--are polyploid lineages "dead-ends" that are prone to rapid extinction, or do they instead drive evolutionary novelty? This empirical study is well positioned to make a key contribution to understanding the evolutionary importance of polyploidy, with implications for evolutionary theory, biodiversity conservation, and crop improvement.

可以说，最引人注目的突变可能（全基因组复制，或多倍体）导致一个个体的染色体数量是其父母的两倍。多倍体是植物中常见且持续存在的现象，其中许多作物例如是多倍体。该项目旨在研究蕨类植物多倍体谱系的进化潜力和命运，蕨类植物是一个几乎所有物种在其进化历史中都经历过一次或多次多倍体事件的植物类群。全球分布的蕨类植物属Cystopteris包括二倍体和多倍体物种的复杂混合，使其成为研究多倍体对多样化率的影响的理想选择。利用200个Cystopteris个体的DNA序列数据，每个已知的倍性水平，进化关系将被推断，祖先倍性水平将被重建，物种形成和灭绝率将被估计。尽管它的普遍性和科学重要性，多倍体的长期潜力和进化动力仍然存在争议-多倍体谱系是容易迅速灭绝的“死胡同”，还是它们反而推动了进化的新奇？这项实证研究是很好的定位，使一个关键的贡献，了解多倍体的进化重要性，与进化理论，生物多样性保护和作物改良的影响。