Plasticity of Fitness and Diversification Process During an Experimental Molecular Evolution
Plasticity of Fitness and Diversification Process During an Experimental Molecular Evolution
复制标题
实验分子进化过程中适应度的可塑性和多样化过程
DOI：
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发表时间：
2001
影响因子：
3.9
通讯作者：
T. Yomo
中科院分区：
文献类型：
--
作者：
A. Kashiwagi;Wataru Noumachi;M. Katsuno;M. Alam;I. Urabe;T. Yomo
抽象的。设计了一个包含自然进化本质的简化实验进化，试图理解其中的机制。在我们的系统中，分子进化观察到通过三个连续的周期的连续随机诱变的谷氨酰胺合成酶基因和恒化培养的转化大肠杆菌细胞含有突变的基因。选择压力只施加在谷氨酰胺合成酶基因的突变基因的品种竞争时，在一个非结构化的环境恒化器。从每个恒化器运行中分离的基因的核苷酸序列推导出分子遗传学和种群动力学。每个周期的初始突变群体由多种紧密相关的基因组成，最终以多种突变体共存的状态结束。在第一个周期的最终群体中两个突变基因之间的竞争确定了所观察到的共存状态不是偶然事件，并且通过环境营养物质的细胞相互作用是共存的可能机制。此外，在上一代中曾经灭绝的突变基因被发现具有再入侵的能力，并构成了分子进化后期周期的基因库。这些结果，包括纯化的野生型和突变型谷氨酰胺合成酶的系统发育树中的动力学特征，揭示了酶活性的分化，而不是优化，在进化过程中的最佳值。在这里，我们提出，可塑性的基因适应性的结果，通过环境的细胞相互作用是一个重要的机制，管理分子进化。
Abstract. A simplified experimental evolution encompassing the essence of natural one was designed in an attempt to understand the involved mechanism. In our system, molecular evolution was observed through three serial cycles of consecutive random mutagenesis of the glutamine synthetase gene and chemostat culture of the transformed Escherichia coli cells containing the mutated genes. Selection pressure was imposed solely on the glutamine synthetase gene when varieties of mutant genes compete in an unstructured environment of the chemostat. The molecular phylogeny and population dynamics were deduced from the nucleotide sequences of the genes isolated from each of the chemostat runs. An initial mutant population in each cycle, comprised of diversified closely-related genes, ended up with several varieties of mutants in a state of coexistence. Competition between two mutant genes in the final population of the first cycle ascertained that the observed coexisting state is not an incidental event and that cellular interaction via environmental nutrients is a possible mechanism of coexistence. In addition, the mutant gene once extinct in the previous passage was found to have the capacity to reinvade and constitute the gene pool of the later cycle of molecular evolution. These results, including the kinetic characteristics of the purified wild-type and mutant glutamine synthetases in the phylogenetic tree, revealed that the enzyme activity had diverged, rather than optimized, to a fittest value during the course of evolution. Here, we proposed that the plasticity of gene fitness in consequence of cellular interaction via the environment is an essential mechanism governing molecular evolution.
影响因子：
3.3
作者：
R. Helling;Christopher N. Vargas;Julian Adams
通讯作者：
R. Helling;Christopher N. Vargas;Julian Adams
影响因子：
3.3
作者：
D. Hartl;D. Dykhuizen;A. Dean;A. Dean
通讯作者：
D. Hartl;D. Dykhuizen;A. Dean;A. Dean
DOI：
10.1101/gr.2.1.28
发表时间：
1992-08-01
期刊：
PCR methods and applications
影响因子：
--
作者：
Cadwell, R C;Joyce, G F
通讯作者：
Joyce, G F