O'Fallon Brendan D, Adler Frederick R, Proulx Stephen R
Department of Biology, University of Utah, 257 South 1400 East, Salt Lake City, UT 84112, USA.
Proc Biol Sci. 2007 Dec 22;274(1629):3159-64. doi: 10.1098/rspb.2007.1228.
Most models of quasi-species evolution predict that populations will evolve to occupy areas of sequence space with the greatest concentration of neutral sequences, thus minimizing the deleterious mutation rate and creating mutationally 'robust' genomes. In contrast, empirical studies of the principal model of quasi-species evolution, RNA viruses, suggest that the effects of deleterious mutations are more severe than in similar DNA-based microbes. We demonstrate that populations divided into discrete patches connected by dispersal may favour genotypes where the deleterious effect of non-neutral mutations is maximized. This effect is especially strong in the absence of back mutation and when the amount of time spent in hosts prior to dispersal is intermediate. Our results indicate that RNA viruses that produce acute infections initiated by a small number of virions are expected to evolve fragile genetic architectures when compared with other RNA viruses.
大多数准种进化模型预测，种群将进化至占据中性序列浓度最高的序列空间区域，从而将有害突变率降至最低，并创造出具有突变“稳健性”的基因组。相比之下，对准种进化主要模型（RNA病毒）的实证研究表明，有害突变的影响比类似的DNA微生物更为严重。我们证明，通过扩散连接的离散斑块中的种群可能更青睐非中性突变有害效应最大化的基因型。在没有回复突变且扩散前在宿主中停留的时间处于中等水平时，这种效应尤为强烈。我们的结果表明，与其他RNA病毒相比，由少量病毒粒子引发急性感染的RNA病毒预计会进化出脆弱的遗传结构。
