Deterministic and stochastic regimes of asexual evolution on rugged fitness landscapes
Deterministic and stochastic regimes of asexual evolution on rugged fitness landscapes
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DOI：
10.1534/genetics.106.067165
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发表时间：
2007-03-01
期刊：
影响因子：
3.3
通讯作者：
Krug, Joachim
中科院分区：
文献类型：
--
作者：
Jain, Kavita;Krug, Joachim
我们研究了一个初始不适应的无性种群的适应动态，该种群的基因类型由长度为L的二进制序列表示。该种群在一个具有大量局部最优解的最大粗糙适应度环境中进化。我们发现，进化轨迹是确定性的还是随机性的，取决于种群在基因空间中传播的有效突变距离d(Ef)。对于d(Ef)=L，确定性准物种理论适用，而对于d(Ef)<；1，演化是完全随机的。在这两种极限情况下，在交叉时间T-X以下用局部准物种理论描述动态，而在T-X以上种群被困在局部适应度峰值，并通过随机隧穿或双突变设法找到更好的峰值。在随机区域d(Ef)<；1中，我们分别识别了与克隆干扰和上坡自适应行走相关的两个子区域。我们认为，我们的发现与对微生物种群进化实验的解释有关。
We study the adaptation dynamics of an initially maladapted asexual Population with genotypes represented by binary sequences of length L. The population evolves in a maximally rugged fitness landscape with a large number of local optima. We find that whether the evolutionary trajectory is deterministic or stochastic depends on the effective mutational distance d(eff) up to which the population can spread in genotype space. For d(eff) = L, the deterministic quasi-species theory operates while for d(eff) < 1, the evolution is completely stochastic. Between these two limiting cases, the dynamics are described by a local quasi-species theory below a crossover time T-X while above T-X the population gets trapped at a local fitness peak and manages to find a better peak via either stochastic tunneling or double mutations. In the stochastic regime d(eff) < 1, we identify two subregimes associated with clonal interference and uphill adaptive walks, respectively. We argue that our findings are relevant to the interpretation of evolution experiments with microbial populations.