The evolution of bet-hedging adaptations to rare scenarios
The evolution of bet-hedging adaptations to rare scenarios
复制标题
DOI：
10.1016/j.tpb.2007.08.006
复制
发表时间：
2007-12-01
影响因子：
1.4
通讯作者：
Masel, Joanna
中科院分区：
文献类型：
--
作者：
King, Oliver D.;Masel, Joanna
当面对多变的环境时，生物可能会根据一定的概率规律在不同的策略之间切换。在一个无限的种群中，人们认为进化会倾向于使几何平均适应度最大化的规则。如果某些环境很少遇到，选择可能不够强大，无法进化出最优切换概率。本文通过分析指定切换规则的等位基因的固定概率，计算有限种群中切换概率的演化。我们计算了作为一种下注对冲形式的表型切换进化所需的条件，作为种群规模N的函数，遇到稀有环境的速率theta，以及与稀有环境中的切换相关的选择优势s。我们考虑了一个简化模型，其中环境切换和表型切换是单向过程，突变是对称的，相对于固定事件的时间尺度很少。在这种情况下，对至少为R的比率有利的押注对冲的近似要求是sN > log(R)和N > root R (c) 2007 Elsevier Inc。版权所有。
When faced with a variable environment, organisms may switch between different strategies according to some probabilistic rule. In an infinite population, evolution is expected to favor the rule that maximizes geometric mean fitness. If some environments are encountered only rarely, selection may not be strong enough for optimal switching probabilities to evolve. Here we calculate the evolution of switching probabilities in a finite population by analyzing fixation probabilities of alleles specifying switching rules. We calculate the conditions required for the evolution of phenotypic switching as a form of bet-hedging as a function of the population size N, the rate theta at which a rare environment is encountered, and the selective advantage s associated with switching in the rare environment. We consider a simplified model in which environmental switching and phenotypic switching are one-way processes, and mutation is symmetric and rare with respect to the timescale of fixation events. In this case, the approximate requirements for bet-hedging to be favored by a ratio of at least R are that sN > log(R) and N theta > root R. (c) 2007 Elsevier Inc. All rights reserved.