Department of Biology, College of Charleston, Charleston, South Carolina 29401, USA.
Evolution. 2012 Jul;66(7):2335-9. doi: 10.1111/j.1558-5646.2012.01583.x. Epub 2012 Feb 21.
Despite the fundamental importance of mutation to the evolutionary process, we have little knowledge of the direct consequences of specific spontaneous mutations to the fitness of the organism. Combining results of whole-genome sequencing with repeated field assays of survival and reproduction, we quantify the combined effects on fitness of spontaneous mutations identified in Arabidopsis thaliana. We demonstrate that the effects are beneficial, deleterious, or neutral depending on the environmental context. Some lines, bearing mutations disrupting known loci, differ strongly in fitness from the founder or premutation genotype. Those effects vary across environments, for example, a line with a major deletion spanning a transcription factor gene expressed lower fitness than the founder under most conditions but exceeded the founder's fitness in one environment. The large contribution of genotype by environment interaction (G × E) to mutation effects on fitness implies spatial and/or temporal variation in selection on new mutations and could contribute to the maintenance of standing genetic variation.
尽管突变对进化过程至关重要，但我们对特定自发突变对生物体适应性的直接后果知之甚少。通过将全基因组测序的结果与生存和繁殖的重复野外试验相结合，我们量化了在拟南芥中鉴定出的自发突变对适应性的综合影响。我们证明，这些影响是有益的、有害的还是中性的，这取决于环境背景。一些携带破坏已知基因座突变的品系，其适应性与原始品系或前突变基因型有很大差异。这些影响在不同环境中有所不同，例如，一个跨越转录因子基因表达的主要缺失的品系在大多数情况下比原始品系的适应性低，但在一种环境中超过了原始品系的适应性。基因型与环境互作（G×E）对突变适应性的影响的巨大贡献意味着对新突变的选择在空间和/或时间上存在差异，这可能有助于维持遗传变异。
