DISSERTATION RESEARCH: The Genetic Basis of Adaptation in Thermally Adapted Escherichia Coli

论文研究：热适应性大肠杆菌适应的遗传基础Albert班尼特和Michelle Riehle本项目将采用基因组方法来理解对高温的适应。 研究人员将检查大肠杆菌的种群，大肠杆菌是一种存在于所有哺乳动物肠道植物群中的微生物，已在实验室高温下培养了2000代。 他们将研究适应高温的遗传基础，适应高温的不同品系之间的平行进化程度，以及种群暴露于较低温度时的可逆性表型和遗传变化。这项工作涉及三个主要目标。第一个目标是研究对高温的适应如何改变基因的拷贝数，通过复制增加拷贝数或通过删除减少拷贝数。第二个目标是研究对温度的适应如何影响基因表达水平。最后，考虑到不断变化的热条件，生物体在表型或生物体水平上如何反应，以及它们在遗传水平上如何反应？有什么特别的模式吗？生物体水平的变化是否总是由相同的遗传变化引起的，或者多种遗传变化是否会产生相同的表型变化？DNA高密度阵列将用于筛选整个基因组的基因复制和缺失区域，并表征基因表达。 这种全基因组方法是一种强大的工具，因为它允许同时筛选所有4290个E。大肠杆菌基因，使所有4290个基因的单独检查是不必要的。这项工作很重要，因为它开始剖析自达尔文时代以来一直吸引着比较生物学家和进化生物学家的复杂适应过程。

DISSERTATION RESEARCH: The Genetic Basis of Adaptation in Thermally Adapted Escherichia ColiAlbert Bennett and Michelle RiehleThis project will take a genomic approach to understanding of adaptation to high temperature. The PIs will examine populations of Escherichia coli, a microbe present in the intestinal flora of all mammals, that have been cultured in the laboratory for 2000 generations at high temperature. They will examine the genetic basis of adaptation to high temperature, the degree of parallel evolution among different lines adapted to high temperature, and the reversability phenotypic and genetic changes upon exposure of populations to lower temperatures. The work addresses three main goals. The first goal is to examine how adaptation to high temperature changes the copy number of genes, either increasing copy number via duplication or decreasing copy number via deletion. The second goal is to examine how adaptation to temperature affects the level of gene expression. Lastly, given changing thermal conditions, how do organisms respond on the phenotypic or organismal level and how do they respond on the genetic level? Is there a particular pattern? Are changes at the organismal level always caused by the same genetic change, or can multiple genetic changes yield the same change in phenotype? DNA high-density arrays will be used to screen whole genomes for regions of gene duplication and deletion, and to characterize gene expression. This whole genome approach is a powerful tool in that it allows the simultaneous screening of all 4290 E. coli genes, making individual examination of all 4290 genes unnecessary. This work is important because it begins to dissect the complex process of adaptation that has intrigued comparative and evolutionary biologists ever since the time of Darwin.