Spatial Structure of Ecological Opportunity Drives Adaptation in a Bacterium
Spatial Structure of Ecological Opportunity Drives Adaptation in a Bacterium
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DOI：
10.1086/666609
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发表时间：
2012-08-01
影响因子：
2.9
通讯作者：
Kassen, Rees
中科院分区：
文献类型：
--
作者：
Bailey, Susan F.;Kassen, Rees
丰富的生态机会被认为是推动适应和多样化的动力。多个机会的存在导致了不同的选择，当特定的利基有益突变具有拮抗的多效性效应时，这可能会减缓适应。另一方面，对多个机会的竞争可能会产生不同的选择，从而导致高适应性差异化。结果如何，可能取决于这些生态机会的空间结构。在混合资源中，对多个机会的竞争可以驱动不同的选择；然而，如果每个资源在空间上不同的斑块中可用，则不可能同时发生对多个机会的竞争。我们报道了生态机会的程度和空间结构对1000代荧光假单胞菌种群进化动态的影响。我们通过改变糖资源(甘露糖、葡萄糖和木糖)的数量来改变生态机会的程度，我们通过提供混合或空间上不同的斑块来改变空间结构。我们看到，一种特别新颖的资源(木糖)在混合提供时推动了适应速度，但对多样性没有影响。相反，我们看到了单一适应战略的演变，这种战略在表型和专业化程度方面有所不同，取决于生态机会的程度和空间结构。
Abundant ecological opportunity is thought to drive adaptation and diversification. The presence of multiple opportunities leads to divergent selection, which can slow adaptation when niche-specific beneficial mutations have antagonistically pleiotropic effects. Alternately, competition for multiple opportunities can generate divergent selection, which leads to high rates of adaptive differentiation. Which outcome occurs may depend on the spatial structure of those ecological opportunities. In a mixture of resources, competition for multiple opportunities can drive divergent selection; however, if each resource is available in a spatially distinct patch, simultaneous competition for multiple opportunities cannot occur. We report the effects of the extent and spatial structure of ecological opportunity on the evolutionary dynamics of populations of Pseudomonas fluorescens over 1,000 generations. We varied the extent of ecological opportunity by varying the number of sugar resources (mannose, glucose, and xylose), and we varied spatial structure by providing resources in either mixtures or spatially distinct patches. We saw that a particularly novel resource (xylose) drove the rate of adaptation when provided in a mixture but had no effect on diversity. Instead, we saw the evolution of a single adaptive strategy that differed with respect to phenotype and degree of specialization, depending on both the extent and the spatial structure of ecological opportunity.