Environmental heterogeneity enhances clonal interference
Environmental heterogeneity enhances clonal interference
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DOI：
10.1111/j.1558-5646.2008.00380.x
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发表时间：
2008-06-01
期刊：
影响因子：
3.3
通讯作者：
Gordo, Isabel
中科院分区：
文献类型：
--
作者：
Campos, Paulo R. A.;Neto, Pedro S. C. A.;Gordo, Isabel
克隆干扰（CI）是几种无性微生物中可能很重要的现象。当种群规模较大，新的有益等位基因的突变率显著时，就会发生这种情况。本文探讨了基因流和空间异质性在无性动物适应中选择强度的作用。我们考虑的是一个细分的个体群体，它们正在适应，通过新的有益的突变，并在不同的补丁之间迁移。每个突变的适应度效应取决于补丁，并且假设所有考虑的突变都是无条件有益的。研究发现，选择压力的空间变异影响着适应进化的速度，其质量效应取决于基因流的水平。特别是，我们发现低迁移和高异质性都会导致CI增强。相反，对于高水平的迁移，当环境异质性存在时，适应性突变的固定率更高。此外，我们观察到适应度变异水平更高，在低迁移率和高异质性的情况下，多个突变的同时固定往往发生。
Clonal interference (CI) is a phenomenon that may be important in several asexual microbes. It occurs when population sizes are large and mutation rates to new beneficial alleles are of significant magnitude. Here we explore the role of gene flow and spatial heterogeneity in selection strength in the adaptation of asexuals. We consider a subdivided population of individuals that are adapting, through new beneficial mutations, and that migrate between different patches. The fitness effect of each mutation depends on the patch and all mutations considered are assumed to be unconditionally beneficial. We find that spatial variation in selection pressure affects the rate of adaptive evolution and its qualitative effects depend on the level of gene flow. In particular, we find that both low migration and high levels of heterogeneity lead to enhanced CI. In contrast, for high levels of migration the rate of fixation of adaptive mutations is higher when environmental heterogeneity is present. In addition, we observe that the level of fitness variation is higher and simultaneous fixation of multiple mutations tends to occur in the regime of low migration rates and high heterogeneity.