Wichman H A, Badgett M R, Scott L A, Boulianne C M, Bull J J
Department of Biological Sciences, University of Idaho, Moscow, ID 83844, USA.
Science. 1999 Jul 16;285(5426):422-4. doi: 10.1126/science.285.5426.422.
The molecular basis of adaptation is a major focus of evolutionary biology, yet the dynamic process of adaptation has been explored only piecemeal. Experimental evolution of two bacteriophage lines under strong selection led to over a dozen nucleotide changes genomewide in each replicate. At least 96 percent of the amino acid substitutions appeared to be adaptive, and half the changes in one line also occurred in the other. However, the order of these changes differed between replicates, and parallel substitutions did not reflect the changes with the largest beneficial effects or indicate a common trajectory of adaptation.
适应的分子基础是进化生物学的一个主要焦点，然而适应的动态过程仅得到了零星的探索。在强选择条件下对两个噬菌体品系进行的实验进化，导致每个重复实验中全基因组有十几个核苷酸发生变化。至少96%的氨基酸替换似乎是适应性的，并且一个品系中的一半变化也出现在另一个品系中。然而，这些变化的顺序在重复实验之间有所不同，平行替换既没有反映出具有最大有益效应的变化，也没有表明适应的共同轨迹。
