Genomic Architecture of Adaptation in Yeast Experimental Evolution

智力价值：生物体如何适应新的环境是一个重要的进化问题。基因组测序项目目前正在发现种群内和物种之间的遗传差异。然而，更难确定这些基因变化中的哪些会导致适应，以及如何引起适应。这个项目使用受控实验室条件下酵母种群的进化来观察进化的实际情况。通过使用新的更便宜、更快的测序方法，进化的酵母菌株的基因组可以被解码，并与祖先的创始细胞进行比较。已发现的突变可以被改造成新的菌株，以单独和联合测试它们的效果。这些工程菌株还将被用来研究突变如何控制哪些基因在生长条件下是活跃的。最后，该项目将多次重复进化实验，以确定结果的重复性。结果将允许发现哪些类型的突变负责适应新的环境，它们如何导致适应性变化，以及如果重复进化，相同基因获得突变的频率有多高。由于自然环境的复杂性，简化的实验室系统，如这里使用的系统，为测试这些重要问题提供了明显的优势。更广泛的影响：这项工作将在本科生和公共科学教育、纳入代表性不足的群体以及科学理解方面产生一些更广泛的影响。邓纳姆博士在教育本科生方面有着很好的记录，包括女性、代表性不足的少数族裔，以及主要来自本科院校的学生。这项研究将允许更多的学生参与实质性的、独立的研究。进一步了解进化过程对科学和社会都是有益的。特别是，进化的实验演示是进化变化在行动中的一个令人信服的例子。了解适应也将有助于学习如何通过选择来改良驯化的作物、动物和微生物。

Intellectual Merit: How organisms adapt to new environments is an important evolutionary question. Genome sequencing projects are currently discovering the genetic differences found in populations and between species. However, it is more difficult to determine which of these genetic changes cause adaptation and how. This project uses evolution of yeast populations in controlled laboratory conditions to watch evolution in action. By using new cheaper, faster sequencing methods, the genomes of evolved yeast strains can be decoded and compared to the ancestral founder cell. Discovered mutations can be engineered into new strains to test their effects alone and in combinations. These engineered strains will also be used to ask how mutations control which genes are active under the growth conditions. Finally, the project will repeat the evolution experiment multiple additional times to find how reproducible the results are. Results will allow discovery of what kinds of mutations are responsible for adaptation to new environments, how they lead to adaptive change, and how frequently the same genes acquire mutations if evolution is performed repeatedly. Due to the complexity of natural environments, simplified laboratory systems, like the one employed here, offer distinct advantages for testing these important questions. Broader Impacts: This work will have a number of broader impacts in undergraduate and public science education, inclusion of underrepresented groups, and scientific understanding. Dr. Dunham has a strong record of educating undergraduates, including women, underrepresented minorities, and students from primarily undergraduate institutions. This research will allow more students to participate in substantive, independent research. Further understanding of evolutionary processes is a benefit to science and society. In particular, experimental demonstrations of evolution are a compelling example of evolutionary change in action. Understanding adaptation will also be useful to learning how to improve domesticated crops, animals, and microorganisms through selection.