Department of Integrative Biology, University of Texas at Austin, Austin, Texas, United States of America.
PLoS One. 2011;6(6):e21541. doi: 10.1371/journal.pone.0021541. Epub 2011 Jun 28.
Dispersal is an important mechanism contributing to both ecological and evolutionary dynamics. In metapopulation and metacommunity ecology, dispersal enables new patches to be colonized; in evolution, dispersal counter-acts local selection, leading to regional homogenization. Here, I consider a three-patch metacommunity in which two species, each with a limiting quantitative trait underlain by gene networks of 16 to 256 genes, compete with one another and disperse among patches. Incorporating dispersal among heterogeneous patches introduces a tradeoff not observed in single-patch simulations: if the difference between gene network size of the two species is greater than the difference in dispersal ability (e.g., if the ratio of network sizes is larger than the ratio of dispersal abilities), then genetic architecture drives community outcome. However, if the difference in dispersal abilities is greater than gene network differences, then any adaptive advantages afforded by genetic architecture are over-ridden by dispersal. Thus, in addition to the selective pressures imposed by competition that shape the genetic architecture of quantitative traits, dispersal among patches creates an escape that may further alter the effects of different genetic architectures. These results provide a theoretical expectation for what we may observe as the field of ecological genomics develops.
扩散是促进生态和进化动态的重要机制。在集合种群和集合群落生态学中，扩散使新斑块得以殖民化；在进化过程中，扩散抵消了局部选择，导致区域同质化。在这里，我考虑了一个由三个斑块组成的集合群落，其中两个物种相互竞争，每个物种都有一个受 16 到 256 个基因的基因网络控制的定量特征，它们在斑块之间扩散。在异质斑块之间引入扩散，引入了在单斑块模拟中未观察到的权衡：如果两个物种的基因网络大小差异大于扩散能力的差异（例如，如果网络大小的差异大于扩散能力的差异），那么遗传结构决定群落结果。然而，如果扩散能力的差异大于基因网络差异，那么遗传结构提供的任何适应性优势都会被扩散所取代。因此，除了竞争施加的选择压力塑造了定量特征的遗传结构之外，斑块之间的扩散创造了一种逃避机制，可能会进一步改变不同遗传结构的影响。这些结果为我们在生态基因组学领域发展时可能观察到的情况提供了理论预期。
