Horizontal Gene Transfer in Multicellular Eukaryotes

多细胞真核生物中的水平基因转移

• 批准号: 6875514
• 负责人: JEFFREY D PALMER
• 金额: $ 38.99万
• 依托单位: TRUSTEES OF INDIANA UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-02-01 至 2009-01-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6875514
• 关键词: angiosperms; biological models; evolution; genetic recombination; genome; high throughput technology; mitochondrial DNA; nucleic acid sequence; plant genetics; polymerase chain reaction

DESCRIPTION (provided by applicant): Horizontal gene transfer (HGT) is now recognized as a major evolutionary genetic force driving genomic and phenotypic change in the microbial world -- throughout prokaryotes and in many unicellular eukaryotes (all phagotrophic protists). We and others recently discovered the first evidence for widespread HGT within any group of multicellular eukaryotes, finding that horizontal transfer of mitochondrial genes in plants is both frequent and recent. Many of these transfers yield mitochondrial gene duplications (of vertically and horizontally transmitted homologs), whereas others lead to strikingly chimeric genes (part horizontal/part vertical) or repopulate the genome with genes previously transferred to the nucleus. Some of the transferred genes are intact, expressed, and probably functional. One mitochondrial genome has already been identified with multiple, perhaps many horizontally acquired genes. The goal of this study is to build on these exciting findings and conduct the first comprehensive and rigorous study of HGT in multicellular eukaryotes. Because HGT is a fundamental but poorly understood process in genome evolution, these studies will provide an important new perspective on genome structure and function. The maintenance of an intact, functioning genome is critical for human health, and understanding mechanisms of gene exchange is important to the development of gene therapy. This project focuses on plant mitochondrial genomes because their exceptional propensity for HGT and several other attributes make them a model system for investigating HGT in eukaryotes. Studies include targeted macroarray screens of 4000 plants, all-gene sequencing in 200 diverse plants, whole-genome sequencing in 15 plants with exceptionally extensive HGT, and various follow-up studies on specific cases of high interest from the above. Results will address numerous questions concerning rates, patterns, extents, chimeric consequences, donor/recipient relationships, functionality, and mechanisms of HGT across many lineages of plant mitochondrial genomes. Certain of the mechanistic studies follow from emerging evidence suggesting that certain plants and genes are unusually prone to HGT and that a common mechanism of transfer is physical penetration between parasitic plants and their host plants.

描述(申请人提供)：水平基因转移(HGT)现在被认为是推动微生物世界--整个原核生物和许多单细胞真核生物(所有具有吞噬功能的原生生物)的基因组和表型变化--的主要进化遗传力量。我们和其他人最近发现了在任何一组多细胞真核生物中普遍存在HGT的第一个证据，发现线粒体基因在植物中的水平转移既频繁又最近。其中许多转移产生线粒体基因复制(垂直和水平传递的同源物)，而其他转移导致惊人的嵌合基因(部分水平/部分垂直)或用先前转移到细胞核的基因重新填充基因组。一些被转移的基因是完整的、表达的，并且可能具有功能。一个线粒体基因组已经被识别出有多个，也许是许多水平获得的基因。 这项研究的目标是在这些令人兴奋的发现的基础上，进行第一个全面和严格的多细胞真核细胞中HGT的研究。由于HGT是基因组进化中的一个基本但鲜为人知的过程，这些研究将为基因组结构和功能提供一个重要的新视角。保持一个完整的、功能正常的基因组对人类健康至关重要，而了解基因交换的机制对基因治疗的发展非常重要。 这个项目专注于植物线粒体基因组，因为它们对HGT和其他几个属性的特殊倾向使它们成为研究真核生物中HGT的模型系统。研究包括对4000种植物进行有针对性的大阵列筛选，对200种不同植物进行全基因测序，对15种具有异常广泛的HGT的植物进行全基因组测序，以及对上述高度感兴趣的特定病例进行各种后续研究。这些结果将解决许多问题，涉及HGT的比率、模式、范围、嵌合后果、供体/受体关系、功能和机制，涉及植物线粒体基因组的许多谱系。某些机制研究源于新出现的证据，表明某些植物和基因异常容易发生HGT，转移的一种常见机制是寄生植物和它们的寄主植物之间的物理渗透。