DISSERTATION RESEARCH: Testing the Mutation Models for the Evolution of Microsatellites: An Experimental and Simulation Approach

微卫星是由连续多次重复的小序列单位组成的DNA延伸。重复序列的数量是高度可变的，影响重复序列长度的突变过程的合适模型仍然是一个悬而未决的问题。这项研究将使用实验进化来解决这个问题。酿酒酵母的20个重复种群将在2000代中进化，并将表征累积在6个微卫星座位上的变异。结果将与基于已提出的三个主要突变模型的计算机模拟研究的预测进行比较。如果这些先前存在的模型都没有得到证实，那么在这次实验中获得的广泛和新颖的数据集将被用来开发更合适的模型。微卫星存在于大多数生物的基因组中。微卫星变异分析用于研究种群大小、种群间的遗传分化和物种间的进化关系等基本科学问题。在更广泛的应用层面上，微卫星是在医学研究中绘制基因组图和在法律诉讼中进行法医分析的重要工具。解释所有这些领域的结果通常需要假设影响微卫星变异的突变过程。因此，该项目的结果将在生物学的不同领域产生重要影响。

Microsatellites are stretches of DNA composed of small sequence units that are repeated many times in tandem. The number of repeats is highly mutable, and the appropriate model for the mutational processes affecting repeat length remains an unsolved problem. This research will use experimental evolution to address this problem. Twenty replicate populations of the yeast Saccharomyces cerevisiae will be evolved for 2000 generations and the variation that has accumulated at 6 microsatellite loci will be characterized. The results will be compared to predictions from computer simulation studies based on the three major mutational models that have been proposed. If none of these preexisting models is confirmed, then the extensive and novel data set obtained in this experiment will be employed to develop a more appropriate model.Microsatellites are present in the genomes of most organisms. Analysis of microsatellite variation is used to study such basic scientific questions as population sizes, genetic divergence between populations, and evolutionary relationships between species. At a more applied level, microsatellites are important tools in genome mapping in medical research and forensic analyses in legal proceedings. Interpretation of results in all of these areas typically requires assumptions about the mutational processes affecting microsatellite variation. The results of this project will thus have important implications in diverse areas of biology.