Fixation probability of beneficial mutations in a fluctuating population
Fixation probability of beneficial mutations in a fluctuating population
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DOI：
10.1017/s0016672308000013
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发表时间：
2009-02-01
影响因子：
1.5
通讯作者：
Saether, Bernt-Erk
中科院分区：
文献类型：
--
作者：
Engen, Steinar;Lande, Russell;Saether, Bernt-Erk
我们计算一个精确的近似固定的概率为一个有益的突变在一个群体波动与一个固定的分布人口规模。假设种群规模足够大，可以忽略人口统计学方差，种群动态由具有环境方差的theta-logistic模型描述。我们发现，人口规模的随机波动减少固定的概率。然而，造成这种减少的并不是人口波动的幅度本身。只有环境变量对固定的概率有实质性的影响。密度依赖的强度（或预期的恢复平衡时间）和密度调节的函数形式，由theta-logistic模型中的参数theta给出，对固定概率的影响很小。因此，基于调和平均群体规模的有效群体规模将低估波动群体中有益突变的预期固定率。
We compute an accurate approximation to the probability of fixation for a beneficial mutation in a population fluctuating with a stationary distribution Of Population size. The population dynamics are described by the theta-logistic model with environmental variance, assuming that the population size is large enough to ignore demographic variance. We show that stochastic fluctuations of population size reduce the probability of fixation. However, it is not the magnitude of the population fluctuations per se that creates this reduction. Only the environmental variance has a substantial effect on the probability of fixation. The strength of density dependence (or expected return time to equilibrium) and the functional form of density-regulation, given by the parameter theta in the theta-logistic model, have little effect on the fixation probability. Effective population size based on harmonic mean population size will therefore underestimate the expected fixation rate of beneficial mutations in fluctuating populations.