Bradley Timothy J, Folk Donna G
Department of Ecology and Evolutionary Biology, University of California, Irvine, CA 92697, USA.
Physiol Biochem Zool. 2004 Jan-Feb;77(1):1-9. doi: 10.1086/381466.
Selection studies are useful if they can provide us with insights into the patterns and processes of evolution in populations under controlled conditions. In this context it is particularly valuable to be able to analyze the limitations of and constraints on evolutionary responses to allow predictions concerning evolutionary change. The concept of a selection pathway is presented as a means of visualizing this predictive process and the constraints that help define the population's response to selection. As pointed out by Gould and Lewontin, history and chance are confounding forces that can mask or distort the adaptive response. Students of the evolutionary responses of organisms are very interested in the effects of these confounding forces, since they play a critical role not only in the laboratory but also in natural selection in the field. In this article, we describe some methods that are a bit different from those used in most studies for examining data from laboratory selection studies. These analytical methods are intended to provide insights into the physiological mechanisms by which evolutionary responses to the environment proceed. Interestingly, selection studies often exhibit disparate responses in replicate populations. We offer methods for analyzing these disparate responses in replicate populations to better understand this very important source of variability in the evolutionary response. We review the techniques of Travisano et al. and show that these approaches can be used to investigate the relative roles of adaptation, history, and chance in the evolutionary responses of populations of Drosophila melanogaster to selection for enhanced desiccation resistance. We anticipate that a wider application of these techniques will provide valuable insights into the organismal, genetic, and molecular nature of the constraints, as well as the factors that serve to enhance or, conversely, to mask the effects of chance. Such studies should help to provide a more detailed understanding of the processes producing evolutionary change in populations.
如果选择研究能够让我们在可控条件下洞察种群进化的模式和过程，那么它就是有用的。在这种情况下，能够分析进化响应的局限性和限制因素，以便对进化变化进行预测，就显得尤为重要。选择路径的概念被提出，作为一种可视化这种预测过程以及有助于定义种群对选择反应的限制因素的方法。正如古尔德和列万廷所指出的，历史和偶然性是混淆因素，会掩盖或扭曲适应性反应。研究生物进化响应的学者对这些混淆因素的影响非常感兴趣，因为它们不仅在实验室中，而且在野外的自然选择中都起着关键作用。在本文中，我们描述了一些方法，这些方法与大多数用于检验实验室选择研究数据的方法略有不同。这些分析方法旨在深入了解进化对环境的响应所通过的生理机制。有趣的是，选择研究在重复种群中常常表现出不同的反应。我们提供了分析这些重复种群中不同反应的方法，以便更好地理解进化反应中这个非常重要的变异性来源。我们回顾了特拉维萨诺等人的技术，并表明这些方法可用于研究适应、历史和偶然性在黑腹果蝇种群对增强抗干燥能力选择的进化反应中的相对作用。我们预计，这些技术的更广泛应用将为限制因素的生物体、遗传和分子本质，以及增强或相反掩盖偶然性影响的因素提供有价值的见解。此类研究应有助于更详细地理解种群中产生进化变化的过程。
