RESEARCH INITIATION - Using Gene Trees to Uncover the Role of Hybridization and Polyploidy in Leucaena (Fabaceae)

研究启动 - 利用基因树揭示杂交和多倍体在银合欢（豆科）中的作用

• 批准号: 0542228
• 负责人: C. Donovan Bailey
• 金额: $ 16.11万
• 依托单位: New Mexico State University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-03-01 至 2009-02-28
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0542228&HistoricalAwards=false
• 关键词: RESEARCH; INITIATION; Using; Gene; Trees

Intellectual Merit: The duplication of chromosome sets (polyploidy) and interspecific hybridization are critical mechanisms known to generate novel genotypes and species diversity. Furthermore, recent advances in genomic techniques and data analysis have suggested that polyploidy and hybridization played more fundamental roles in major evolutionary events than previously recognized. These discoveries along with the tremendous range of consequences induced by these mechanisms identify that we are only touching the tip of the iceberg when it comes to both our understanding of the distribution of hybridization and polyploidy and their potential actions. In this proposal I outline a project whose goals are to advance the understanding of the distribution of these phenomena as well as the application of new tools in research programs focused on relationships among closely related plant species. Through this work I intend to elucidate relationships among divergent and reticulate species in the legume genus Leucaena, a group that has been a focus of my recent research program and that will form a core component of future studies.The Study System: The 22 species of Leucaena include presumed extant divergent diploid progenitors with derived taxa/individuals of hybrid, autopolyploid, and allopolyploid origins all within a fairly restricted geographic distribution. The prevalence of hybridization and polyploidy among species of Leucaena (Fabaceae) help to make it an important system in the study of plant evolutionary biology. In addition, general interest in systematic research on Leucaena has been sparked by connections to ongoing indigenous plant domestication and the status of some taxa as invasive weeds in the tropics. Several studies have attempted to elucidatethe origins of polyploid and hybrid species of Leucaena; however, a lack of sufficiently variable data continues to hinder the development of clearly supported hypotheses that are critical for the understanding of their origin(s) and subsequent study on the specific impact of these mechanisms on evolution.Objectives: The specific research objectives of this proposal are to: 1) use a novel strategy to develop multiple sufficiently variable DNA sequence based data sets from Leucaena to fully investigate divergent and reticulate relationships among taxa; 2) demonstrate the utility of the novel SCAR-based strategy in phylogenetic studies; 3) complete a web-based database that will facilitate the dissemination of the growing body of information on Leucaena to the broader research community; and 4) educate and inspire undergraduate and graduate student participants from a minority serving institution.Broader impacts: Findings from this study will provide critical evidence for the general role of hybridization and polyploidy in a genus of chiefly neotropical trees that includes species undergoing domestication. In addition, the tools developed will help to address problems resolving phylogenies that have been commonplace in angiosperm systematics. The funding and implementation of this project will generate training and educational opportunities for graduate and undergraduate students at a minority serving institution in a laboratory with a record of attracting and training individuals who represent minority groups. All students involved in this project will develop expertise in taxonomy, systematics, molecular biology, and bioinformatics.Furthermore, the completion of the data base on Leucaena will supply a comprehensive global resource for information on this developing system that will ideally attract the attention of other researchers interested in using Leucaena to study the genomic impacts of hybridization, polyploidy, and domestication.

智力优势：染色体组的重复（多倍体）和种间杂交是产生新基因型和物种多样性的重要机制。 此外，基因组技术和数据分析的最新进展表明，多倍性和杂交在重大进化事件中发挥的作用比以前认识到的更重要。这些发现沿着由这些机制引起的巨大范围的后果表明，当涉及到我们对杂交和多倍体的分布及其潜在作用的理解时，我们只是触及了冰山一角。在这份提案中，我概述了一个项目，其目标是促进对这些现象的分布的理解，以及在研究项目中应用新工具，重点是密切相关的植物物种之间的关系。通过这项工作，我打算阐明在豆科植物银合欢属，一组一直是我最近的研究计划的重点，并将形成未来研究的核心组成部分分歧和网状物种之间的关系。银合欢属的22个种包括推测的现存分歧二倍体祖先，其衍生的分类群/个体为杂种、同源多倍体、和异源多倍体起源都在一个相当有限的地理分布范围内。银合欢属（豆科）种间杂交和多倍体的普遍存在使其成为植物进化生物学研究的重要系统。此外，对银合欢属植物进行系统研究的普遍兴趣是由于与正在进行的本土植物驯化和一些分类群在热带地区作为入侵杂草的地位有关。几项研究试图阐明银合欢属多倍体和杂交种的起源;然而，缺乏足够的可变数据继续阻碍发展明确支持的假说，这些假说对于理解其起源和随后研究这些机制对进化的具体影响至关重要。目的：本提案的具体研究目标是：1）使用一种新的策略来开发多个足够可变的基于DNA序列的数据集，以充分研究分类群之间的分歧和网状关系：2）证明基于SCAR的新策略在系统发育研究中的实用性; 3）完成一个基于网络的数据库，这将有助于向更广泛的研究界传播关于银合欢的越来越多的信息;和4）教育和激励本科生和研究生的参与者从少数服务机构。更广泛的影响：这项研究的结果将提供关键的证据，杂交和多倍体的一般作用，主要是新热带树木，包括物种正在驯化。此外，开发的工具将有助于解决被子植物系统学中常见的系统发育问题。这一项目的资助和实施将为研究生和本科生在一个少数群体服务机构的实验室提供培训和教育机会，该实验室有吸引和培训少数群体代表的记录。所有参与该项目的学生将培养分类学、系统学、分子生物学和生物信息学方面的专业知识。此外，银合欢数据库的建成将为这个正在发展的系统提供一个全面的全球信息资源，这将理想地吸引其他有兴趣利用银合欢研究杂交、多倍体和驯化的基因组影响的研究人员的注意。