New Zealand Institute For Advanced Study, Massey University at Albany, Private Bag 102904, North Shore Mail Centre, Auckland 0745, New Zealand.
Biol Lett. 2011 Feb 23;7(1):98-100. doi: 10.1098/rsbl.2010.0547. Epub 2010 Jul 21.
Theoretical studies of adaptation emphasize the importance of understanding the distribution of fitness effects (DFE) of new mutations. We report the isolation of 100 adaptive mutants-without the biasing influence of natural selection-from an ancestral genotype whose fitness in the niche occupied by the derived type is extremely low. The fitness of each derived genotype was determined relative to a single reference type and the fitness effects found to conform to a normal distribution. When fitness was measured in a different environment, the rank order changed, but not the shape of the distribution. We argue that, even with detailed knowledge of the genetic architecture underpinning the adaptive types (as is the case here), the DFEs remain unpredictable, and we discuss the possibility that general explanations for the shape of the DFE might not be possible in the absence of organism-specific biological details.
适应性的理论研究强调了理解新突变适应度效应（DFE）分布的重要性。我们报告了从一个祖先基因型中分离出 100 个适应性突变体，这些突变体没有自然选择的偏向影响，而这个祖先基因型在衍生类型占据的小生境中的适应性非常低。每个衍生基因型的适应性都相对于一个单一的参考类型来确定，发现适应性效应符合正态分布。当在不同的环境中测量适应性时，等级顺序发生了变化，但分布的形状没有变化。我们认为，即使我们详细了解了支持适应性类型的遗传结构（就像这里的情况一样），DFE 仍然是不可预测的，我们还讨论了在没有特定于生物体的生物学细节的情况下，DFE 形状的一般解释可能是不可能的可能性。
