Orlenko Alena, Hermansen Russell A, Liberles David A
Department of Biology and Center for Computational Genetics and Genomics, Temple University, Philadelphia, PA, 19122, USA.
Department of Molecular Biology, University of Wyoming, Laramie, WY, 82071, USA.
J Mol Evol. 2016 Mar;82(2-3):146-61. doi: 10.1007/s00239-016-9731-2. Epub 2016 Feb 26.
Biochemical thought posits that rate-limiting steps (defined here as points of flux control) are strongly selected as points of pathway regulation and control and are thus expected to be evolutionarily conserved. Conversely, population genetic thought based upon the concepts of mutation-selection-drift balance at the pathway level might suggest variation in flux controlling steps over evolutionary time. Glycolysis, as one of the most conserved and best characterized pathways, was studied to evaluate its evolutionary conservation. The flux controlling step in glycolysis was found to vary over the tree of life. Further, phylogenetic analysis suggested at least 60 events of gene duplication and additional events of putative positive selection that might alter pathway kinetic properties. Together, these results suggest that even with presumed largely negative selection on pathway output on glycolysis, the co-evolutionary process under the hood is dynamic.
生化理论认为，限速步骤（在此定义为通量控制节点）作为途径调控和控制的关键节点会被强烈选择，因此预计在进化过程中会保持保守。相反，基于途径水平上突变 - 选择 - 漂变平衡概念的群体遗传学理论可能表明，通量控制步骤在进化时间内会发生变化。糖酵解作为最保守且特征最明确的途径之一，被用于研究其进化保守性。研究发现，糖酵解中的通量控制步骤在生命之树上存在差异。此外，系统发育分析表明至少有60次基因复制事件以及可能改变途径动力学特性的推定正选择事件。这些结果共同表明，即使假定对糖酵解途径输出的选择在很大程度上是负向的，其背后的共同进化过程也是动态的。
