Victoria University of Wellington, Wellington 6140, New Zealand.
Proc Biol Sci. 2013 May 15;280(1762):20130211. doi: 10.1098/rspb.2013.0211. Print 2013 Jul 7.
Ecological factors exert a range of effects on the dynamics of the evolutionary process. A particularly marked effect comes from population structure, which can affect the probability that new mutations reach fixation. Our interest is in population structures, such as those depicted by 'star graphs', that amplify the effects of selection by further increasing the fixation probability of advantageous mutants and decreasing the fixation probability of disadvantageous mutants. The fact that star graphs increase the fixation probability of beneficial mutations has lead to the conclusion that evolution proceeds more rapidly in star-structured populations, compared with mixed (unstructured) populations. Here, we show that the effects of population structure on the rate of evolution are more complex and subtle than previously recognized and draw attention to the importance of fixation time. By comparing population structures that amplify selection with other population structures, both analytically and numerically, we show that evolution can slow down substantially even in populations where selection is amplified.
生态因素对进化过程的动态产生了一系列影响。一个特别显著的影响来自于种群结构，它可以影响新突变达到固定的概率。我们感兴趣的是种群结构，如“星状图”所示，通过进一步增加有利突变的固定概率和降低不利突变的固定概率，放大选择的影响。星状图增加有益突变的固定概率这一事实导致了这样的结论，即在星状结构的种群中，与混合（无结构）种群相比，进化过程更快。在这里，我们表明，种群结构对进化速度的影响比以前认识到的更加复杂和微妙，并提请注意固定时间的重要性。通过比较分析和数值模拟，我们展示了在选择被放大的种群中，进化甚至可以大大减慢，即使在选择被放大的种群中也是如此。
