Interaction between mutation type and gene pleiotropy drives parallel evolution in the laboratory

What causes evolution to be repeatable is a fundamental question in evolutionary biology. Pleiotropy, i.e. the effect of an allele on multiple traits, is thought to enhance repeatability by constraining the number of available beneficial mutations. Additionally, pleiotropy may promote repeatability by allowing large fitness benefits of single mutations via adaptive combinations of phenotypic effects. Yet, this latter evolutionary potential may be reaped solely by specific types of mutations able to realize optimal combinations of phenotypic effects while avoiding the costs of pleiotropy. Here, we address the interaction of gene pleiotropy and mutation type on evolutionary repeatability in a meta-analysis of experimental evolution studies with Escherichia coli. We hypothesize that single-nucleotide polymorphisms are principally able to yield large fitness benefits by targeting highly pleiotropic genes, whereas indels and structural variants provide smaller benefits and are restricted to..., ,进化可重复的成因是进化生物学领域的一个根本性科学问题。多效性（pleiotropy），即单个等位基因对多种性状的影响，被认为可通过限制可用有益突变的数量来提升进化可重复性。此外，多效性还可通过表型效应的适应性组合，使单个突变获得较高的适合度收益，进而促进进化可重复性。然而，这一后一种进化潜力，仅能被那些能够实现最优表型效应组合且规避多效性代价的特定突变类型所利用。本研究通过对大肠杆菌（Escherichia coli）的实验进化研究开展荟萃分析，探讨了基因多效性与突变类型对进化可重复性的交互影响。我们提出假说：单核苷酸多态性（single-nucleotide polymorphisms）主要可通过靶向高多效性基因，获得较高的适合度收益；而插入缺失变异（indels）与结构变异（structural variants）则仅能带来较低的适合度收益，且其作用范围受限……