Mutumi Gregory L, Jacobs David S, Winker Henning
Animal Evolution and Systematics Group (AES) Department of Biological Sciences University of Cape Town Cape Town South Africa.
Department of Biology University of Massachusetts Amherst 221 Morrill Science Center Amherst MA 01003 USA.
Ecol Evol. 2017 May 9;7(12):4299-4311. doi: 10.1002/ece3.2966. eCollection 2017 Jun.
Natural selection and drift can act on populations individually, simultaneously or in tandem and our understanding of phenotypic divergence depends on our ability to recognize the contribution of each. According to the quantitative theory of evolution, if an organism has diversified through neutral evolutionary processes (mutation and drift), variation of phenotypic characteristics between different geographic localities () should be directly proportional to the variation within localities (), that is, ∝. Significant deviations from this null model imply that non-neutral forces such as natural selection are acting on a phenotype. We investigated the relative contributions of drift and selection to intraspecific diversity using southern African horseshoe bats as a test case. We characterized phenotypic diversity across the distributional range of (101) and ( 125) using several traits associated with flight and echolocation. Our results suggest that geographic variation in both species was predominantly caused by disruptive natural selection ( was not directly proportional to ). Evidence for correlated selection (co-selection) among traits further confirmed that our results were not compatible with drift. Selection rather than drift is likely the predominant evolutionary process shaping intraspecific variation in traits that strongly impact fitness.
自然选择和遗传漂变可以单独、同时或相继作用于种群，而我们对表型分化的理解取决于我们识别每种因素贡献的能力。根据进化的定量理论，如果一个生物体通过中性进化过程（突变和遗传漂变）实现了多样化，那么不同地理区域（）之间表型特征的变异应该与区域内的变异（）成正比，即 ∝。与这个零模型的显著偏差意味着诸如自然选择等非中性力量正在作用于一种表型。我们以南非菊头蝠为测试案例，研究了遗传漂变和选择对种内多样性的相对贡献。我们使用与飞行和回声定位相关的几个特征，对 （101 只）和 （125 只）分布范围内的表型多样性进行了表征。我们的结果表明，两个物种的地理变异主要是由破坏性自然选择引起的（与 不成正比）。性状间相关选择（共选择）的证据进一步证实我们的结果与遗传漂变不相符。选择而非遗传漂变可能是塑造对适应性有强烈影响的性状种内变异的主要进化过程。
