Experimental Evolutionary Studies of Temperature Adaptation

将测量对温度的长期进化适应 在大肠杆菌中进行实验。 原本 建立的实验品系（祖先）保持在37 ℃。 随后，在2000年之后获得了多组复制系 几代人暴露在32 ℃，42 ℃和每天交替的温度下， 以及维持在37公里的控制线， C. 这些实验将确定每一种 适应了各自的温度。 测量 变量将包括合成和运输的变化 能力、抗压能力和人口增长性能。 还将在较高温度（42 ℃）下选择管线， 确定热上限是否可以延长， 相关的变化负责增加温度耐受性。 本研究拟解决以下问题： 生物系统能迅速地对 环境变化？--一个人的进化史 环境条件或适应新事物的能力 环境？--是否对特定环境进行适应 或者有很多解决方案， 事件？ 本研究涉及的具体问题包括： 在不同的热环境中的适应率和限制， 在适应性进化过程中的权衡程度， 历史环境的进一步适应， 在类似环境中进化过程中的机械适应， 以及环境对突变过程的影响。

Long-term evolutionary adaptation to temperature will be measured experimentally in the bacterium Escherichia coli. Originally the founding experimental line (the ancestor) was maintained at 37 C. Subsequently, groups of replicated lines were obtained after 2000 generations of exposure to 32 C, 42 C, and a daily alternation between them, as well as control lines which were maintained at 37 C. These experiments will determine the mechanisms by which each of these groups adapted to their respective temperatures. Measured variables will include changes in synthetic and transport capacities, stress resistance, and population growth performance. Lines will also be selected at higher (42 C) temperatures to determine whether the upper thermal limit can be extended and the correlated changes responsible for increased temperature tolerance. The research proposes to address the following questions: --How rapidly can biological systems respond evolutionarily to environmental change? --Does prior evolutionary history in one environment condition or predispose ability to adapt to novel environments? --Does adaptation to a particular environment proceed by similar mechanisms or are there as many solutions as adaptive events? Specific issues addressed by this research include the rate and limits of adaptation in diverse thermal environments, the extent of trade-offs during adaptive evolution, the effect of historical environment on further adaptation, the concordance of mechanistic adaptations during evolution in similar environments, and environmental effects on mutational processes.