Connections among Genotype, Phenotype and Fitness in Escherichia coli High Temperature Lines

大肠杆菌高温系基因型、表型和适应性之间的联系

• 批准号: 1257427
• 负责人: Brandon Gaut
• 金额: $ 65.95万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-04-01 至 2018-03-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1257427&HistoricalAwards=false
• 关键词: Connections; among; Genotype; Phenotype; Fitness; Connections; among; Genotype; Phenotype; Fitness

An improved understanding of the process of evolutionary genetic adaptation must rely in part on a better understanding of how genetic changes are linked to changes in structural and functional characteristics of organisms (phenotypes) that result in improved reproductive success (i.e., fitness). However, the relationship between genotype and phenotype is not well understood, limiting an understanding of the evolutionary process. The work funded by this award will investigate the relationship between genotype and phenotype on an unprecedented scale in the bacterium Escherichia coli. The bacterium has been adapted through artificial selection experiments to thermal stress (42.2 C) for one year in over 100 replicate populations. A clone from each population has been genotyped completely by genomic sequencing. This grant will characterize the phenotypes of these replicate populations and then relate these phenotypes explicitly to the known genotypes. The phenotypes that will be measured include patterns of gene expression and features of cell metabolism. Of particular interest will be a contrast between clones that adapted by mutations in either the transcriptional termination gene rho or the RNA polymerase subunit gene rpoB. The work will determine whether these different genetic solutions lead to similar functional changes in phenotypes and whether the two adaptive pathways are mutually exclusive. To address the latter issue, mutations of both rho and rpoB will be introduced into a single genetic background, and the evolutionary fitness of double mutants will be determined at high temperature. By characterizing both phenotypic changes and genetic interactions associated with adaptation, this work will impact the heart of evolutionary theory, including classical views on the adaptive process. In addition, this project will continue a successful outreach project that introduced K-12 teachers to lab modules that facilitate "hands on" teaching of evolution in the classroom, based on the E. coli model.

对进化遗传适应过程的改进理解必须部分依赖于更好地理解遗传变化如何与生物体的结构和功能特征（表型）的变化相关联，从而改善了生殖成功（即适应性）。 但是，基因型与表型之间的关系尚不清楚，从而限制了对进化过程的理解。该奖项资助的工作将在细菌大肠杆菌中以前所未有的规模研究基因型和表型之间的关系。 在100多个重复种群中，通过人工选择实验对热应激（42.2 c）进行了调整。每个人群的克隆已通过基因组测序完全基因分型。 该赠款将表征这些重复种群的表型，然后将这些表型明确地与已知的基因型联系起来。 将测量的表型包括基因表达的模式和细胞代谢的特征。特别令人感兴趣的是由转录终止基因RHO或RNA聚合酶亚基基因rPOB中突变适应的克隆之间的对比。 这项工作将确定这些不同的遗传溶液是否导致表型的相似功能变化以及两种自适应途径是否相互排斥。 为了解决后一个问题，RHO和RPOB的突变将被引入单个遗传背景，并将在高温下确定双突变体的进化适应性。通过表征表型变化和与适应性相关的遗传相互作用，这项工作将影响进化论的核心，包括对自适应过程的经典观点。 此外，该项目将继续一个成功的外展项目，该项目将K-12教师介绍给实验室模块，这些模块促进了基于大肠杆菌模型的课堂进化教学的“动手”教学。