Competition and the origins of novelty: experimental evolution of niche-width expansion in a virus
Competition and the origins of novelty: experimental evolution of niche-width expansion in a virus
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DOI：
10.1098/rsbl.2012.0616
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发表时间：
2013-02-23
期刊：
影响因子：
3.3
通讯作者：
Burch, Christina L.
中科院分区：
文献类型：
--
作者：
Bono, Lisa M.;Gensel, Catharine L.;Burch, Christina L.
长期以来，对资源的竞争一直被视为分歧选择的关键因素。理论认为，面临严重种内竞争的种群将倾向于使用更广泛的资源，甚至可能使用需求较少的全新资源。然而，对这些想法的实验测试却很少。利用细菌病毒（噬菌体）phi 6作为模型系统，我们研究了对宿主资源的竞争是否促进了新的资源利用的进化。在实验室中，phi 6表现出狭窄的宿主范围，但很容易产生能够感染新型细菌宿主的突变体。在这里，我们表明，当phi 6群体受到激烈的种内竞争，以获得标准的实验室宿主时，它们迅速进化出新的多面手形态，感染新的宿主。因此，我们的研究结果表明，对宿主资源的竞争可能会推动病毒宿主范围扩展的进化。更一般地说，我们的研究结果表明，种内资源竞争确实可以促进新的资源利用表型的进化。
Competition for resources has long been viewed as a key agent of divergent selection. Theory holds that populations facing severe intraspecific competition will tend to use a wider range of resources, possibly even using entirely novel resources that are less in demand. Yet, there have been few experimental tests of these ideas. Using the bacterial virus (bacteriophage) phi 6 as a model system, we examined whether competition for host resources promotes the evolution of novel resource use. In the laboratory, phi 6 exhibits a narrow host range but readily produces mutants capable of infecting novel bacterial hosts. Here, we show that when phi 6 populations were subjected to intense intraspecific competition for their standard laboratory host, they rapidly evolved new generalist morphs that infect novel hosts. Our results therefore suggest that competition for host resources may drive the evolution of host range expansion in viruses. More generally, our findings demonstrate that intraspecific resource competition can indeed promote the evolution of novel resource-use phenotypes.