Dissertation Research: The Fate of Novel Genetic Mutation at a Single Locus Under Selection in Escherichia coli

9623838 Riley研究突变如何影响生物体的一个中心假设是，大多数突变是有害的。这一假设从未经过实验检验。这项由该奖项资助的研究的目标是通过确定新的遗传变异的命运来检验这一假设。尽管我们目前对产生突变的分子生物学过程有所了解，但一旦突变产生的性状受到自然选择的影响，关于引入的变异如何或在多大程度上在自然界中得以维持，我们所知甚少。为了解决这个问题，Wagner和Riley将评估许多不同的突变对细菌生存能力和生长的影响，细菌是一种可以在短时间内测试多种突变影响的生物体。一种被称为随机诱变的技术将被用于在细菌中产生单个基因的许多不同的突变副本，并且将确定哪些突变是有益的，哪些是有害的，哪些没有影响。我们将探究这三类突变的确切化学性质，以揭示是否存在对生物体有益或有害的特定类型的突变。利用这些信息，生物学家就有可能将积极作用的突变纳入有益生物体，或将有害突变纳入害虫基因型。结果也可能促进细菌的工程执行某些功能，其中许多可能在工业过程中有用。

9623838 Riley A central assumption in the study of how mutation affects organisms is that the majority of mutations are harmful. This asqumption has never been experimentally tested. The goal of the research funded by this award is to test this assumption by determining the fate of novel genetic variation. Despite our current knowledge of the molecular biological processes which create mutation, little information is known about how or how much of the introduced variation is maintained in nature once a trait produced by the mutation is subjected to natural selection. To address this issue, Wagner and Riley will assess the effects of many different mutations on the viability and growth of bacteria, which are organisms that allow testing the effects of many kinds of mutations in a short period of time. A technique called random mutagenesis will be used to create many different mutated copies of a single gene in a bacterium, and the fraction of mutations that are beneficial, harmful, or have no effect will be determined. The exact chemical nature of the mutations from each of these three classes will be probed, to reveal whether there are particular types of mutations that are associated with benefit or harm to the organism. Using this information, it may then be possible for biologists to incorporate mutations of positive effect into beneficial organisms or harmful mutations into pest genotypes. Results may also facilitate the engineering of bacteria to perform certain functions, many of which may be useful in industrial processes.