Pepin Kim M, Wichman Holly A
Department of Biological Sciences, University of Idaho, Moscow, Idaho 83844, USA.
Evolution. 2007 Jul;61(7):1710-24. doi: 10.1111/j.1558-5646.2007.00143.x.
Epistatic interactions between mutations are widespread. Theoretical investigations have shown that variability in epistatic effects influences fundamental evolutionary processes, yet few empirical studies have identified causes or the extent of this variation. We examined variation in epistatic effects of mutations at two host recognition sites in phiX174 bacteriophage. We calculated epistatic effects from the sum of fitness effects (log scale) of two single mutants and their corresponding double mutant for five combinations of mutations in six conditions. We found that epistatic effects differed in sign, degree, and variability across conditions. The data highlight that even between single mutations at the same two sites the sign and variability of epistatic effects are affected by environment. We discuss these findings in the context of studying the role of epistasis in evolution.
突变之间的上位性相互作用广泛存在。理论研究表明，上位性效应的变异性会影响基本的进化过程，但很少有实证研究确定这种变异的原因或程度。我们研究了φX174噬菌体两个宿主识别位点突变的上位性效应变异。我们针对六种条件下五种突变组合，通过两个单突变体及其相应双突变体的适合度效应（对数尺度）之和计算上位性效应。我们发现，上位性效应在不同条件下的符号、程度和变异性存在差异。这些数据突出表明，即使是同一两个位点的单突变之间，上位性效应的符号和变异性也会受到环境的影响。我们在研究上位性在进化中的作用的背景下讨论了这些发现。
