Bennett A F, Dao K M, Lenski R E
Department of Ecology and Evolutionary Biology, University of California, Irvine 92717.
Nature. 1990 Jul 5;346(6279):79-81. doi: 10.1038/346079a0.
Temperature is an important environmental factor affecting all organisms, and there is ample evidence from comparative physiology that species and even conspecific populations can adapt genetically to different temperature regimes. But the effect of these adaptations on fitness and the rapidity of their evolution is unknown, as is the extent to which they depend on pre-existing genetic variation rather than new mutations. We have begun a study of the evolutionary adaptation of Escherichia coli to different temperature regimes, taking advantage of the large population sizes and short generation times in experiments on this bacterial species. We report significant improvement in temperature-specific fitness of lines maintained at 42 degrees C for 200 generations (about one month). These changes in fitness are due to selection on de novo mutations and show that some biological systems can evolve rapidly in response to changes in environmental factors such as temperature.
温度是影响所有生物体的重要环境因素，比较生理学有充分证据表明，物种甚至同种生物种群都能在基因上适应不同的温度环境。但这些适应性对适合度的影响及其进化速度尚不清楚，它们在多大程度上依赖于预先存在的基因变异而非新突变也不清楚。我们利用大肠杆菌实验中种群数量大且世代时间短的特点，开始了对大肠杆菌适应不同温度环境的进化研究。我们报告称，在42摄氏度下维持200代（约一个月）的品系，其特定温度下的适合度有显著提高。适合度的这些变化是由于对新生突变的选择，表明一些生物系统能够迅速进化以应对温度等环境因素的变化。
