Molina Chai, Earn David J D
Department of Mathematics and Statistics, McMaster University, 1280 Main Street West, Hamilton, ON, L8S 4K1, Canada.
J Math Biol. 2018 Feb;76(3):645-678. doi: 10.1007/s00285-017-1151-4. Epub 2017 Jun 29.
Two major forces shaping evolution are drift and selection. The standard models of neutral drift-the Wright-Fisher (WF) and Moran processes-can be extended to include selection. However, these standard models are not always applicable in practice, and-even without selection-many other drift models make very different predictions. For example, "generalised Wright-Fisher" models (so-called because their first two conditional moments agree with those of the WF process) can yield wildly different absorption times from WF. Additionally, evolutionary stability in finite populations depends only on fixation probabilities, which can be evaluated under less restrictive assumptions than those required to estimate fixation times or more complex population-genetic quantities. We therefore distill the notion of a selection process into a broad class of finite-population, mutationless models of drift and selection (including the WF and Moran processes). We characterize when selection favours fixation of one strategy over another, for any selection process, which allows us to derive finite-population conditions for evolutionary stability independent of the selection process. In applications, the precise details of the selection process are seldom known, yet by exploiting these new theoretical results it is now possible to make rigorously justifiable inferences about fixation of traits.
塑造进化的两大主要力量是漂变和选择。中性漂变的标准模型——赖特-费希尔（WF）模型和莫兰过程——可以扩展到包含选择。然而，这些标准模型在实际中并非总是适用，而且——即使没有选择——许多其他漂变模型也会做出非常不同的预测。例如，“广义赖特-费希尔”模型（之所以这样称呼是因为它们的前两个条件矩与WF过程的相同）可能会产生与WF模型大不相同的吸收时间。此外，有限种群中的进化稳定性仅取决于固定概率，与估计固定时间或更复杂的种群遗传数量所需的假设相比，固定概率可以在限制较少的假设下进行评估。因此，我们将选择过程的概念提炼为一类广泛的有限种群、无突变的漂变和选择模型（包括WF模型和莫兰过程）。对于任何选择过程，我们都刻画了选择何时有利于一种策略而非另一种策略的固定，这使我们能够得出与选择过程无关的有限种群进化稳定性条件。在应用中，选择过程的确切细节很少为人所知，但通过利用这些新的理论结果，现在有可能对性状的固定做出严格合理的推断。
