Evolution of Duplicated Pathways and Networks Following Genome Doubling

基因组加倍后重复通路和网络的进化

• 批准号: 1118646
• 负责人: Jonathan Wendel
• 金额: $ 72.71万
• 依托单位: Iowa State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-09-01 至 2017-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1118646&HistoricalAwards=false
• 关键词: Evolution; Duplicated; Pathways; Networks; Following

Intellectual Merit. A central finding of modern plant biology is that plant lineages often originate from and diversify following hybridization between species and subsequent doubling of the hybrid genome. This biological reunion among two different genomes sets in motion a wide spectrum of genetic and genomic phenomena with that occur through unknown mechanisms and have largely unknown functional and evolutionary consequences. To advance understanding of the dynamics and outcomes of genome doubling, this project will study the consequences of genome merger and doubling on pathways and networks. Using the cotton genus (Gossypium) as a well-developed model for studies of whole-genome doubling, this study will focus on two different pathways and networks. For the anthocyanin biosynthetic pathway, multiple relationships among mutational processes, changes in gene expression, and metabolite accumulation will be clarified. Using a second, more complex network involving flowering time, experiments will address responses of a network to the intense directional selection practiced by early cotton domesticators as the wild species was transformed by humans from a wild, photoperiod-sensitive, perennial plant into a day-length neutral, annualized row crop. Remarkably, this process was replicated for two different species, providing a unique opportunity to test the repeatability of the response to selective breeding. The research entails three complementary experimental approaches. First, using novel technologies, all genes for the key proteins involved in the core anthocyanin biosynthetic pathway and the approximately 70 proteins involved in the flowering time network will be isolated and sequenced from the progenitor genomes, as well as from domesticated and wild forms of two different cultivated species of cotton. Second, changes in gene expression will be detailed for each evolutionary stage in the process, including hybridization, genome doubling, and human selection during crop improvement. Third, the consequences of genome doubling on metabolite accumulation will be studied for the anthocyanin pathway. Synthesis of these three data sources will reveal the interrelationships among mutations, gene expression, and metabolite accumulation, during the evolutionary processes of species divergence, inter-genomic hybridization, and genome doubling. Collectively, these studies will provide a novel perspective on an important process in plant biology, with broad conceptual generality and applicability. Broader Impacts: Multiple activities are planned that target inclusion and training of students from underrepresented groups and provide research experiences for students and K-12 educators. The project has a special focus on a seven-week summer research experience for teachers program, which provides 7th -12th grade biology teachers with an opportunity to enhance their understanding of scientific inquiry while introducing them to cutting-edge science. Teachers will learn theory and methods in workshops and conduct independent projects associated with larger on-going projects. They will receive hands-on training in modern laboratory techniques, including those associated with gene sequence and gene expression analysis, metabolite accumulation, and bioinformatics. Also, teachers will meet weekly under the guidance of selected experienced master teachers to discuss transfer of their research experiences into the 7th -12th grade science classroom. To provide teachers with a deeper understanding and appreciation evolutionary biology, Wendel will lead a teacher training study group each summer, with the explicit focus of incorporating molecular genetics perspectives into the teaching of evolutionary biology. At the end of each summer session, teachers will prepare a plan for implementing research-based education modules in the classroom.

知识价值。现代植物生物学的一个中心发现是，植物谱系通常起源于物种之间的杂交，并在杂交基因组随后加倍后多样化。两种不同基因组之间的这种生物学上的重聚，启动了一系列遗传和基因组现象，这些现象通过未知的机制发生，并在很大程度上具有未知的功能和进化后果。为了进一步了解基因组加倍的动力学和结果，本项目将研究基因组合并和加倍对途径和网络的影响。利用棉花属（Gossypium）作为研究全基因组加倍的成熟模型，本研究将重点关注两种不同的途径和网络。对于花青素生物合成途径，将阐明突变过程、基因表达变化和代谢物积累之间的多重关系。使用第二个更复杂的网络，包括开花时间，实验将解决网络对早期棉花驯化者所进行的强烈定向选择的反应，因为野生物种被人类从野生的，光周期敏感的多年生植物转变为一天长度的中性，一年生行作物。值得注意的是，这一过程在两个不同的物种中被复制，为测试选择性育种反应的可重复性提供了一个独特的机会。这项研究需要三种互补的实验方法。首先，利用新技术，将从祖先基因组以及驯化和野生两种不同栽培品种的棉花中分离和测序涉及核心花青素生物合成途径的关键蛋白的所有基因和大约70个涉及开花时间网络的蛋白质。其次，基因表达的变化将在过程的每个进化阶段，包括杂交，基因组加倍，和人类选择在作物改良过程中详细。第三，将研究基因组加倍对花青素途径代谢物积累的影响。这三个数据源的综合将揭示突变、基因表达和代谢物积累之间的相互关系，在物种分化、基因组间杂交和基因组加倍的进化过程中。总的来说，这些研究将为植物生物学的一个重要过程提供一个新的视角，具有广泛的概念概括性和适用性。更广泛的影响：计划开展多项活动，目标是纳入和培训来自代表性不足群体的学生，并为学生和K-12教育工作者提供研究经验。该项目特别关注为期七周的暑期教师研究体验项目，该项目为7 -12年级的生物教师提供了一个机会，在向他们介绍前沿科学的同时提高他们对科学探究的理解。教师将在研讨会中学习理论和方法，并进行与大型正在进行的项目相关的独立项目。他们将接受现代实验室技术的实践培训，包括与基因序列和基因表达分析、代谢物积累和生物信息学相关的技术。此外，教师将在选定的经验丰富的大师教师的指导下每周会面，讨论将他们的研究经验转移到7 -12年级的科学课堂。为了让老师们对进化生物学有更深的理解和欣赏，温德尔每年夏天都会带领一个教师培训学习小组，将分子遗传学的观点纳入进化生物学的教学中。在每个暑期课程结束时，教师将准备在课堂上实施研究型教育模块的计划。