DISSERTATION RESEARCH: Quantitative test of evolutionary bet-hedging theory in a mirobial model system

论文研究：微生物模型系统中进化赌注对冲理论的定量检验

• 批准号: 1501355
• 负责人: Daniel Weinreich
• 金额: $ 2.11万
• 依托单位: Brown University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2017-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1501355&HistoricalAwards=false
• 关键词: DISSERTATION; RESEARCH; Quantitative; test; evolutionary

This project will provide understanding of the fundamental principles that influence adaptation in changing environments. Evolutionary theory predicts that natural selection in changing environments will favor traits so long as they confer a net benefit over time. This context of adaptation in changing environments is central to understanding many traits, such as the ability to sense and respond to the environment, and drug resistance of pathogenic microorganisms. This research will therefore help to elucidate the evolutionary processes underlying medically important traits. The researchers will also develop and distribute a lesson plan aimed at teaching the basic tenets of adaptation in changing environments to high school students, thus helping to raise public awareness about a biologically relevant problem.Biological traits such as phenotypic plasticity and bet-hedging are presumed to evolve by increasing the long-term geometric mean fitness of a lineage. This framework serves as a useful description of the average selective advantage of traits in a variable environment. However, there are known theoretical limitations with this approach since it fails to explicitly capture evolutionary dynamics of evolving populations and thus does not provide a mechanistic description of the evolutionary origin and maintenance of traits such as bet-hedging. Using laboratory yeast populations adapted to rapid periods of environmental stress, the researchers will experimentally measure evolutionary dynamics of competing bet-hedging strategies in a variable environment. The researchers will use a combination of genome sequencing and reverse genetics to construct a panel of fluorescently labeled yeast strains that express differing bet-hedging strategies. By carefully tracking the abundance of competing strains during the course of competition experiments in variable environments, the researchers will directly compare evolutionary changes in the laboratory to the predictions of computational models of adaptation in varying environments. In doing so, the research will generate data necessary to directly test of the geometric mean fitness concept and will experimentally determine the extent of its limitations for describing adaptation to varying environments.

该项目将帮助人们了解影响不断变化的环境适应的基本原则。进化论预测，不断变化的环境中的自然选择将有利于特征，只要它们能随着时间的推移带来净收益。这种适应不断变化的环境的背景对于理解许多特征至关重要，例如感知和响应环境的能力以及病原微生物的耐药性。因此，这项研究将有助于阐明重要医学特征的进化过程。研究人员还将制定并分发一个课程计划，旨在向高中生讲授适应不断变化的环境的基本原则，从而帮助提高公众对生物学相关问题的认识。推测表型可塑性和赌注对冲等生物学特征通过增加谱系的长期几何平均适应性来进化。该框架可以有效描述可变环境中性状的平均选择优势。然而，这种方法存在已知的理论局限性，因为它无法明确捕获进化种群的进化动态，因此无法提供进化起源和赌注对冲等特征维持的机械描述。研究人员将利用适应快速环境压力的实验室酵母菌群，通过实验测量可变环境中竞争性下注对冲策略的进化动态。研究人员将结合基因组测序和反向遗传学来构建一组荧光标记的酵母菌株，这些菌株表达不同的对冲策略。通过在可变环境中的竞争实验过程中仔细跟踪竞争菌株的丰度，研究人员将直接将实验室中的进化变化与不同环境中适应计算模型的预测进行比较。在此过程中，研究将生成直接测试几何平均适应度概念所需的数据，并将通过实验确定其在描述对不同环境的适应方面的局限性程度。