The Relationship between Spatial Structure and the Maintenance of Diversity in Microbial Populations
The Relationship between Spatial Structure and the Maintenance of Diversity in Microbial Populations
复制标题
DOI：
10.1086/701799
复制
发表时间：
2019-04-01
影响因子：
2.9
通讯作者：
Forney, Larry J.
中科院分区：
文献类型：
--
作者：
France, Michael T.;Forney, Larry J.
空间结构在微生物世界中普遍存在，但我们对其如何影响微生物种群的进化知之甚少。人们认为，空间结构限制了竞争互动的规模，延长了选择性扫荡的时间。这可能允许微生物群体同时探索多条进化路径。但在实现这一效应之前，微生物种群必须有怎样的结构尚不清楚。我们采用实证研究和模拟研究相结合的方法来探讨空间结构与多样性维持之间的关系。大肠杆菌集合种群经历的空间结构程度是通过改变其组成亚群之间的迁移率来操纵的。每个亚群接种相同数量的两种等值基因，并在150代的进化过程中测定了它们在12个亚群中的频率。我们观察到，随着亚种群间迁移率的增加，“失败者”基因型的频率呈指数下降，而在结构化集合种群中，失败者基因型的频率保持较高的频率。这些结果表明，即使在亚种群之间的迁移率相对较高的情况下，结构化微生物种群也可以沿着多种进化轨迹进化。
Spatial structure is pervasive in the microbial world, yet we know little about how it influences the evolution of microbial populations. It is thought that spatial structure limits the scale of competitive interactions and protracts selective sweeps. This may allow microbial populations to simultaneously explore multiple evolutionary paths. But how structured a microbial population must be before this effect is realized is not known. We used empirical and simulation studies to explore the relationship between spatial structure and the maintenance of diversity. The degree of spatial structure experienced by Escherichia coli metapopulations was manipulated by varying the migration rate between its component subpopulations. Each subpopulation was inoculated with an equal number of two equally fit genotypes, and their frequencies in 12 subpopulations were determined during 150 generations of evolution. We observed that the frequency of the "loser" genotypes decreased exponentially as the migration rate between the subpopulations was increased and that higher frequencies of the loser genotypes were maintained in structured metapopulations. These results demonstrate that structured microbial populations can evolve along multiple evolutionary trajectories even when migration rates between the subpopulations are relatively high.