Department of Physics and Astronomy, McMaster University, 1280 Main St. West, Hamilton, ON L8M 4S1, Canada.
Viruses. 2023 May 10;15(5):1135. doi: 10.3390/v15051135.
RNA viruses may be monopartite (all genes on one strand), multipartite (two or more strands packaged separately) or segmented (two or more strands packaged together). In this article, we consider competition between a complete monopartite virus, A, and two defective viruses, D and E, that have complementary genes. We use stochastic models that follow gene translation, RNA replication, virus assembly, and transmission between cells. D and E multiply faster than A when stored in the same host as A or when together in the same host, but they cannot multiply alone. D and E strands are packaged as separate particles unless a mechanism evolves that allows assembly of D + E segmented particles. We show that if defective viruses assemble rapidly into separate particles, the formation of segmented particles is selected against. In this case, D and E spread as parasites of A, and the bipartite D + E combination eliminates A if the transmissibility is high. Alternatively, if defective strands do not assemble rapidly into separate particles, then a mechanism for assembly of segmented particles is selected for. In this case, the segmented virus can eliminate A if transmissibility is high. Conditions of excess protein resources favor bipartite viruses, while conditions of excess RNA resources favor segmented viruses. We study the error threshold behavior that arises when deleterious mutations are introduced. Relative to bipartite and segmented viruses, deleterious mutations favor monopartite viruses. A monopartite virus can give rise to either a bipartite or a segmented virus, but it is unlikely that both will originate from the same virus.
RNA 病毒可能是单链的（所有基因都在一条链上）、双链的（两条或更多条链分别包装）或分段的（两条或更多条链一起包装）。在本文中，我们考虑了一种完整的单链病毒 A，以及两种具有互补基因的缺陷病毒 D 和 E 之间的竞争。我们使用遵循基因翻译、RNA 复制、病毒组装以及细胞间传播的随机模型。当 D 和 E 与 A 储存在同一宿主中或在同一宿主中共存时，它们的繁殖速度比 A 快，但它们不能单独繁殖。D 和 E 链被包装成单独的颗粒，除非出现一种允许组装 D + E 分段颗粒的机制。我们表明，如果缺陷病毒迅速组装成单独的颗粒，那么组装分段颗粒的机制就会被淘汰。在这种情况下，D 和 E 作为 A 的寄生虫传播，并且如果传染性高，则双联体 D + E 组合会消除 A。或者，如果缺陷链不能迅速组装成单独的颗粒，那么组装分段颗粒的机制就会被选择。在这种情况下，如果传染性高，分段病毒可以消除 A。多余的蛋白质资源有利于双联体病毒，而多余的 RNA 资源有利于分段病毒。我们研究了当引入有害突变时出现的误差阈值行为。与双联体和分段病毒相比，有害突变有利于单链病毒。单链病毒可以产生双链或分段病毒，但两者不太可能来自同一病毒。
