Evolution of host specificity drives reproductive isolation among RNA viruses
Evolution of host specificity drives reproductive isolation among RNA viruses
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DOI：
10.1111/j.1558-5646.2007.00226.x
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发表时间：
2007-11-01
期刊：
影响因子：
3.3
通讯作者：
Turner, Paul E.
中科院分区：
文献类型：
--
作者：
Duffy, Siobain;Burch, Christina L.;Turner, Paul E.
生态物种形成假说认为，选择性交配是重要生态特征的不同自然选择的结果。生殖隔离预计特别有可能通过这种机制进化，例如在它们吃的栖息地交配的植食性昆虫。我们通过监测一种RNA病毒的生殖隔离进化来验证这一预期，这种病毒只有在多种病毒基因型共同感染同一宿主时才会进行遗传交换。我们将四个群体的RNA噬菌体phi 6在一个新的宿主上进行了150代的自然选择。虽然在我们的实验中没有直接选择作用于宿主范围，但四个种群中有三个失去了感染一个或多个替代宿主的能力。在最极端的情况下，其中一个种群进化出了一个宿主范围，其中不包含任何可被野生型phi 6感染的宿主。全基因组测序证实，由此产生的生殖隔离是由于单个核苷酸的变化，突出表明新兴RNA病毒可以轻松地将其进化命运与其祖先的进化命运分离开来。我们的结果独特地证明了生殖隔离在异源实验群体中的演变。此外，我们的数据证实了选型交配的简单“无基因”机制的生物学可信度，其中这种特性是由负责生态适应的基因的多效性效应引起的。
Ecological speciation hypotheses claim that assortative mating evolves as a consequence of divergent natural selection for ecologically important traits. Reproductive isolation is expected to be particularly likely to evolve by this mechanism in species such as phytophagous insects that mate in the habitats in which they eat. We tested this expectation by monitoring the evolution of reproductive isolation in laboratory populations of an RNA virus that undergoes genetic exchange only when multiple virus genotypes coinfect the same host. We subjected four populations of the RNA bacteriophage phi 6 to 150 generations of natural selection on a novel host. Although there was no direct selection acting on host range in our experiment, three of the four populations lost the ability to infect one or more alternative hosts. In the most extreme case, one of the populations evolved a host range that does not contain any of the hosts infectible by the wild-type phi 6. Whole genome sequencing confirmed that the resulting reproductive isolation was due to a single nucleotide change, highlighting the ease with which an emerging RNA virus can decouple its evolutionary fate from that of its ancestor. Our results uniquely demonstrate the evolution of reproductive isolation in allopatric experimental populations. Furthermore, our data confirm the biological credibility of simple "no-gene" mechanisms of assortative mating, in which this trait arises as a pleiotropic effect of genes responsible for ecological adaptation.