Immigration-induced phase transition in a regulated multispecies birth-death process
Immigration-induced phase transition in a regulated multispecies birth-death process
复制标题
DOI：
10.1088/1751-8121/aadcb4
复制
发表时间：
2018-08
期刊：
影响因子：
--
通讯作者：
Song Xu;T. Chou
中科院分区：
文献类型：
--
作者：
Song Xu;T. Chou
指数分布的物种数或克隆数存在于许多生物环境中，如多物种细胞种群、种群遗传学和生态学。由k个个体代表的物种数量ck的比例为k的负幂，这一经验观察也得到了一系列理论出生-死亡-移民(BDI)模型的支持，该模型一致地预测了许多低种群物种、少数中等种群物种和非常高种群物种。然而，我们展示了在中立的BDI模型中，一个简单的全球人口依赖的监管是如何破坏幂函数分布的。对受管制的BDI模型的模拟表明，观察到主导总种群的高种群物种的可能性很高。进一步的分析表明，这种破裂的起源与预期物种丰度分布的平均场近似失败有关。我们通过将问题映射到较低维的Moran过程来找到预期分布的准确估计，从而允许我们也直接计算协方差。最后，我们利用与能量景观相关的概念来解释平均场假设的失败，方法是识别由迁移率下降引发的准稳态物种计数中的相变。
Power-law-distributed species counts or clone counts arise in many biological settings such as multispecies cell populations, population genetics, and ecology. This empirical observation that the number of species ck represented by k individuals scales as negative powers of k is also supported by a series of theoretical birth–death–immigration (BDI) models that consistently predict many low-population species, a few intermediate-population species, and very high-population species. However, we show how a simple global population-dependent regulation in a neutral BDI model destroys the power law distributions. Simulation of the regulated BDI model shows a high probability of observing a high-population species that dominates the total population. Further analysis reveals that the origin of this breakdown is associated with the failure of a mean-field approximation for the expected species abundance distribution. We find an accurate estimate for the expected distribution by mapping the problem to a lower-dimensional Moran process, allowing us to also straightforwardly calculate the covariances . Finally, we exploit the concepts associated with energy landscapes to explain the failure of the mean-field assumption by identifying a phase transition in the quasi-steady-state species counts triggered by a decreasing immigration rate.