Optimal Strategy for Competence Differentiation in Bacteria
Optimal Strategy for Competence Differentiation in Bacteria
复制标题
细菌能力分化的最佳策略
作者：
C. Scott Wylie;Aaron D. Trout;David A. Kessler;H. Levine
细菌物种的遗传多样性子集天然地能够通过DNA转化。转化需要不同谱系之间的基因重组，这代表了一种增加遗传变异的细菌性别形式。我们首先评估是否同源重组的转化是有利于进化。使用随机群体遗传计算机模拟，其中有益和有害的突变发生在整个基因组的许多位点，我们发现，转换可以增加适应性进化的速度和平衡水平的健身。其次，受枯草芽孢杆菌的实验观察的启发，我们假设感受态另外需要弱持久表型，即，这些细胞的出生率和死亡率降低。因此，坚持者比非坚持者进化得更慢。我们通过模拟表明，菌株的stochemical开关进入和退出的主管表型是进化上的优势，只表达一个单一的表型的菌株。我们的模型的简单性使我们能够推导出并数值求解一个描述进化动力学的有限确定性方程系统。观察到的重组的好处和持久性的成本之间的权衡可以解释以前神秘的观察，只有一个小部分的亚群B。subtilis细胞表达感受态。更一般地说，这项工作表明，即使在一个不变的和同质的环境中，群体遗传力也可以引起表型多样性。
A phylogenetically diverse subset of bacterial species are naturally competent for transformation by DNA. Transformation entails recombination of genes between different lineages, representing a form of bacterial sex that increases standing genetic variation. We first assess whether homologous recombination by transformation is favored by evolution. Using stochastic population genetic computer simulations in which beneficial and deleterious mutations occur at many loci throughout the whole genome, we find that transformation can increase both the rate of adaptive evolution and the equilibrium level of fitness. Secondly, motivated by experimental observations of Bacillus subtilis, we assume that competence additionally entails a weak persister phenotype, i.e., the rates of birth and death are reduced for these cells. Consequently, persisters evolve more slowly than non-persisters. We show via simulation that strains which stochastically switch into and out of the competent phenotype are evolutionarily favored over strains that express only a single phenotype. Our model's simplicity enables us to derive and numerically solve a system of finite- deterministic equations that describe the evolutionary dynamics. The observed tradeoff between the benefit of recombination and the cost of persistence may explain the previously mysterious observation that only a fractional subpopulation of B. subtilis cells express competence. More generally, this work demonstrates that population genetic forces can give rise to phenotypic diversity even in an unchanging and homogeneous environment.
影响因子：
2
作者：
KEPLER, TB;PERELSON, AS
通讯作者：
PERELSON, AS
DOI：
10.1073/pnas.98.1.182
发表时间：
2001-01-02
影响因子：
11.1
作者：
Feil, EJ;Holmes, EC;Spratt, BG
通讯作者：
Spratt, BG