Tracing Processes of Genome Evolution Using Plantaginaceae

智力优势：在生命的所有领域都存在着非凡的基因组多样性，但对形成基因组结构和功能的进化过程知之甚少。植物的线粒体基因组在真核生物中是非常显著的：它们非常大且高度重组，它们的核苷酸序列进化非常缓慢，它们的基因富含内含子并偶尔进行水平基因转移（HGT），它们的转录本由于RNA编辑而经历了多次修饰。与大多数植物相比，车前草属（Plantaginaceae; Lamiales）物种的线粒体基因组在结构和内容上表现出巨大的差异，包括高取代率，内含子和RNA编辑含量前所未有的减少，以及对HGT的易感性增加。这些事件发生在过去的几百万年里，提供了一个难得的机会来追踪它们的进化，并在短的进化时间尺度上评估它们对基因组结构和功能的影响。比较基因组学研究将在车前子科进行，并与其他植物进行比较，以揭示整个家族在替代率、内含子内容、编辑位点内容和HGT方面的全部多样性。该项目将进一步了解车前草线粒体异常进化趋势的原因和后果，这些结果将为所有生物体基因组结构和内容的进化提供重要的见解。更广泛的影响：该项目致力于培养各种背景和技能水平的科学家，包括妇女、少数民族和从高中到研究生的农村学生。该项目将涉及高中生，他们将通过暑期研究经历参与。此外，还将为本科生、研究生和博士后提供研究培训。外国学生交换计划将为美国学生提供进行国际实地工作的机会，并为国际学生参观PI的实验室学习分子技术。该项目的成果将通过期刊出版物、在国家和国际会议上的介绍以及在内布拉斯加州立大学博物馆一系列公开介绍的一部分广泛传播。

Intellectual merit: There is extraordinary genomic diversity across all domains of life, yet little is understood about the evolutionary processes that shape genome structure and function. The mitochondrial genomes of plants are remarkable among eukaryotes: they are extremely large and highly recombinogenic, their nucleotide sequences evolve very slowly, their genes are intron-rich and occasionally undergo horizontal gene transfer (HGT), and their transcripts experience numerous modifications due to RNA editing. In contrast to most plants, the mitochondrial genomes from species in genus Plantago (Plantaginaceae; Lamiales) exhibit drastic deviations in structure and content including highly elevated substitution rates, unprecedented reductions in intron and RNA editing content, and increased susceptibility to HGT. These events have occurred within the last few million years, providing a rare opportunity to trace their evolution and to evaluate their effects on genome structure and function over a short evolutionary timescale. A comparative genomics study will be performed within the Plantaginaceae, and in comparison to other plants, to reveal the full diversity in substitution rates, intron content, edit site content, and HGT across the family. This project will provide greater understanding of the causes and consequences of the unusual evolutionary trends in Plantago mitochondria, and these results should provide significant insight into the evolution of genome structure and content in all living organisms.Broader impacts: The PI is committed to training scientists of all backgrounds and skill levels including women, minorities, and rural students from the high school to the postgraduate level. This project will involve high school students, who will participate through a summer research experience. In addition, research training will be provided for undergraduates, a graduate student, and a postdoctoral researcher. A foreign student exchange program will provide opportunities for US students to do international field work and for international students to visit the PI's lab to learn molecular techniques. Results of the project will be widely disseminated through journal publications, in presentations at national and international conferences, and as part of a series of public presentations at the University of Nebraska State Museum.