Sackman Andrew M, Reed Danielle, Rokyta Darin R
Department of Biological Science, Florida State University , Tallahassee, FL , United States of America.
PeerJ. 2015 Oct 22;3:e1320. doi: 10.7717/peerj.1320. eCollection 2015.
Horizontal gene transfer and recombination occur across many groups of viruses and play key roles in important viral processes such as host-range expansion and immune-system avoidance. To have any predictive power regarding the ability of viruses to readily recombine, we must determine the extent to which epistasis restricts the success of recombinants, particularly as it relates to the genetic divergence between parental strains. In any hybridization event, the evolutionary success or failure of hybrids is largely determined by the pervasiveness of epistasis in the parental genomes. Recombination has previously been shown to incur steep fitness costs in highly divergent viruses as a result of disrupted epistatic interactions. We used a pair of bacteriophages of the family Microviridae to demonstrate that epistasis may evidence itself in the form of fitness costs even in the case of the exchange of alleles at a locus with amino acid divergence as low as 1%. We explored a possible biophysical source of epistasis in the interaction of viral coat and scaffolding proteins and examined a recovery mutation that likely repairs interactions disrupted by recombination.
水平基因转移和重组发生在许多病毒群体中，并在宿主范围扩大和免疫系统逃避等重要病毒过程中发挥关键作用。为了对病毒易于重组的能力具有任何预测能力，我们必须确定上位性在多大程度上限制了重组体的成功，特别是与亲本菌株之间的遗传差异相关的情况。在任何杂交事件中，杂种的进化成功或失败在很大程度上取决于亲本基因组中上位性的普遍程度。先前已证明，由于上位性相互作用的破坏，重组在高度分化的病毒中会产生巨大的适应性代价。我们使用一对微小病毒科的噬菌体来证明，即使在氨基酸差异低至1%的位点上进行等位基因交换的情况下，上位性也可能以适应性代价的形式表现出来。我们探索了病毒衣壳蛋白和支架蛋白相互作用中上位性的一种可能的生物物理来源，并研究了一个可能修复因重组而破坏的相互作用的恢复突变。
