Section of Integrative Biology, The University of Texas at Austin, Austin, TX, USA.
Mol Biol Evol. 2012 Aug;29(8):2001-18. doi: 10.1093/molbev/mss069. Epub 2012 Feb 15.
Molecular evolution is simultaneously paced by mutation rate, genetic drift, and natural selection. Life history traits also affect the speed of accumulation of nucleotide changes. For instance, small body size, rapid generation time, production of reactive oxygen species (ROS), and high resting metabolic rate (RMR) are suggested to be associated with faster rates of molecular evolution. However, phylogenetic correlation analyses failed to support a relationship between RMR and molecular evolution in ectotherms. In addition, RMR might underestimate the metabolic budget (e.g., digestion, reproduction, or escaping predation). An alternative is to test other metabolic rates, such as active metabolic rate (AMR), and their association with molecular evolution. Here, I present comparative analyses of the associations between life history traits (i.e., AMR, RMR, body mass, and fecundity) with rates of molecular evolution of and mitochondrial loci from a large ectotherm clade, the poison frogs (Dendrobatidae). My results support a strong positive association between mass-specific AMR and rates of molecular evolution for both mitochondrial and nuclear loci. In addition, I found weaker and genome-specific covariates such as body mass and fecundity for mitochondrial and nuclear loci, respectively. No direct association was found between mass-specific RMR and rates of molecular evolution. Thus, I provide a mechanistic hypothesis of the link between AMRs and the rate of molecular evolution based on an increase in ROS within germ line cells during periodic bouts of hypoxia/hyperoxia related to aerobic exercise. Finally, I propose a multifactorial model that includes AMR as a predictor of the rate of molecular evolution in ectothermic lineages.
分子进化同时受到突变率、遗传漂变和自然选择的影响。生活史特征也会影响核苷酸变化的积累速度。例如，较小的体型、快速的世代时间、活性氧（ROS）的产生和较高的静息代谢率（RMR）被认为与分子进化的更快速度有关。然而，系统发育相关分析未能支持 RMR 与变温动物分子进化之间的关系。此外，RMR 可能低估了代谢预算（例如消化、繁殖或逃避捕食）。另一种方法是测试其他代谢率，如主动代谢率（AMR）及其与分子进化的关系。在这里，我提出了对生活史特征（即 AMR、RMR、体重和繁殖力）与大型变温动物类群——毒蛙（箭毒蛙科）的线粒体基因座的分子进化速率之间关联的比较分析。我的结果支持了质量特异性 AMR 与线粒体和核基因座的分子进化速率之间的强烈正相关。此外，我发现了较弱的、基因组特异性的协变量，如体重和繁殖力，分别与线粒体和核基因座有关。质量特异性 RMR 与分子进化速率之间没有直接关联。因此，我提出了一个基于与有氧运动相关的周期性缺氧/富氧期中线粒体细胞内 ROS 增加的机制假说，来解释 AMR 与分子进化速率之间的联系。最后，我提出了一个多因素模型，该模型将 AMR 作为预测变温动物谱系分子进化速率的一个指标。
