Data from: Multiplicity of infection does not accelerate infectivity evolution of viral parasites in laboratory microcosms

Coinfection with multiple parasite genotypes (multiplicity of infection) creates within-host competition and opportunities for parasite recombination, and is therefore predicted to be important for both parasite and host evolution. We tested for a difference in the infectivity of viral parasites (lytic phage Φ2) and resistance of their bacterial hosts (Pseudomonas fluorescens SBW25) under both high and low multiplicity of infection (MOI) during coevolution in laboratory microcosms. Results show that MOI has no effect on infectivity and resistance evolution during coevolution over approximately 80 generations of host growth, and this is true when the experiment is initiated with wild-type viruses and hosts, or with viruses and hosts that have already been coevolving for ~330 generations. This suggests that MOI does not have a net effect of accelerating parasite adaptation to hosts through recombination, or retarding adaptation to hosts through between-parasite conflict in this system.多重寄生虫基因型共感染（即感染复数，multiplicity of infection, MOI）会引发宿主内竞争，并为寄生虫重组提供契机，因此被认为对寄生虫与宿主的演化均具有重要意义。本研究在实验室微宇宙共演化实验中，设置高、低两种感染复数（MOI）条件，检测病毒性寄生虫（裂解性噬菌体Φ2）的感染性与其宿主细菌（荧光假单胞菌SBW25）的抗性是否存在差异。结果显示，在宿主生长约80代的共演化过程中，感染复数对病毒感染性与宿主抗性演化均无显著影响；无论实验初始使用野生型病毒与宿主，还是已完成约330代共演化的病毒与宿主，该结论均成立。这表明，在本实验系统中，感染复数并未通过重组途径加速寄生虫对宿主的适应性演化，也未通过寄生虫间的冲突途径延缓其适应性演化。