High mutation rates, bottlenecks, and robustness of RNA viral quasispecies
High mutation rates, bottlenecks, and robustness of RNA viral quasispecies
复制标题
DOI：
10.1016/j.gene.2004.12.033
复制
发表时间：
2005-03-14
期刊：
影响因子：
3.5
通讯作者：
Lázaro, E
中科院分区：
文献类型：
--
作者：
Manrubia, SC;Escarmís, C;Lázaro, E
种群瓶颈是一种随机事件，它强烈地制约着自然种群的结构和进化。它们的影响在高度异质的种群中很容易观察到，例如RNA病毒，因为瓶颈导致突变的快速积累。考虑到大多数突变都是有害的，预计频繁使用瓶颈将产生无法复制的种群。然而。体外和体内系统通过瓶颈进化呈现出显著的抗灭绝能力。这一观察结果揭示了RNA病毒的健壮性，并指出存在内部机制，必须赋予对快速突变群体的高度适应性。在这篇文章中，我们回顾了关于RNA病毒在实验室实验和自然种群中存活的实验观察。通过一个简单的进化理论模型，其中包含了种群大小的强烈减少，我们探索了单个创始粒子在应用下一个瓶颈之前经历的复制轮数与特定环境中的突变率之间的关系。我们的数值结果表明，突变率与由创始粒子产生的种群所达到的优化程度是一致的。我们假设这种机制在自然种群中产生了一种突变选择平衡，在保持其结构的同时最大化适应性。(c) 2004 Elsevier b.v.版权所有
Population bottlenecks are stochastic events that strongly condition the structure and evolution of natural populations. Their effects are readily observable in highly heterogeneous populations, such as RNA viruses, since bottlenecks cause a fast accumulation of mutations. Considering that most mutations are deleterious, it was predicted that the frequent application of bottlenecks would yield a population unable to replicate. However. in vitro as well as in vivo systems evolving through bottlenecks present a remarkable resistance to extinction. This observation reveals the robustness of RNA viruses and points to the existence of internal mechanisms which must confer a high degree of adaptability to fast mutating populations. In this contribution, we review experimental observations regarding the survival of RNA viruses, both in laboratory experiments and in natural populations. By means of a simple theoretical model of evolution which incorporates strong reductions of the population size, we explore the relationship between the number of replication rounds that a single founder particle undergoes before the next bottleneck is applied, and the mutation rate in a particular environment. Our numerical results reveal that the mutation rate has evolved in a concerted way with the degree of optimization achieved by the population originated from the founder particle. We hypothesize that this mechanism generates a mutation-selection equilibrium in natural populations that maximizes adaptability while maintaining their structure. (c) 2004 Elsevier B.V All rights reserved.