另外,减去,和双链RNA病毒都在自然界中发现。我们使用计算模型来研究这些策略的相对成功。我们考虑翻译,复制,和一个牢房内的病毒体组装,以及病毒体在细胞间的传播.对于没有在衣壳中掺入聚合酶的病毒,仅传输正股是默认策略,因为包含负股的病毒体没有传染性。如果每个细胞产生的RNA链的数量大于衣壳的数量,则仅包装加链具有显著的优势。在这种情况下,通过不包装负线,这种病毒会产生更多的正链病毒粒子。因此,在低感染复数下选择正链病毒。然而,在高感染复数下,最好包装两条链,因为当每个细胞有多个感染时,产生的额外的负病毒粒子是有帮助的。正链病毒很普遍,而包装两条链的病毒在自然界中却没有看到,这一事实表明RNA链确实比衣壳过量产生。并且感染的复数不足以促进两种病毒粒子的产生。对于双链病毒,我们表明,在细胞内只从双链产生正链是有利的,正如在真实病毒中观察到的那样。负链病毒成功的原因最初更令人困惑。对于在病毒体中掺入聚合酶的病毒,负号病毒体具有传染性。然而,这不足以解释负链病毒的成功,因为在这种情况下,包装两股的病毒胜过那些只包装的病毒。真正的负链病毒利用由核蛋白包被的可复制链,和单独的可平移加上未涂层的股线。在这里,我们展示了当存在不同的可复制和可翻译链时,选择负链病毒。
Plus, minus, and double-strand RNA viruses are all found in nature. We use computational models to study the relative success of these strategies. We consider translation, replication, and virion assembly inside one cell, and transmission of virions between cells. For viruses which do not incorporate a polymerase in the capsid, transmission of only plus strands is the default strategy because virions containing minus strands are not infectious. Packaging only plus strands has a significant advantage if the number of RNA strands produced per cell is larger than the number of capsids. In this case, by not packaging minus strands, the virus produces more plus-strand virions. Therefore, plus-strand viruses are selected at low multiplicity of infection. However, at high multiplicity of infection, it is preferable to package both strands because the additional minus virions produced are helpful when there are multiple infections per cell. The fact that plus-strand viruses are widespread while viruses that package both strands are not seen in nature suggests that RNA strands are indeed produced in excess over capsids, and that the multiplicity of infection is not sufficiently high to favor the production of both kinds of virions. For double-strand viruses, we show that it is advantageous to produce only plus strands from the double strand within the cell, as is observed in real viruses. The reason for the success of minus-strand viruses is more puzzling initially. For viruses that incorporate a polymerase in the virion, minus virions are infectious. However, this is not sufficient to explain the success of minus-strand viruses, because in this case, viruses that package both strands outcompete those that package only minus or only plus. Real minus-strand viruses make use of replicable strands that are coated by a nucleoprotein, and separate translatable plus strands that are uncoated. Here we show that when there are distinct replicable and translatable strands, minus-strand viruses are selected.