Rate of novel host invasion affects adaptability of evolving RNA virus lineages

Although differing rates of environmental turnover should be consequential for the dynamics of adaptive change, this idea has been rarely examined outside of theory. In particular, the importance of RNA viruses in disease emergence warrants experiments testing how differing rates of novel host invasion may impact the ability of viruses to adaptively shift onto a novel host. To test whether the rate of environmental turnover influences adaptation, we experimentally evolved 144 Sindbis virus lineages in replicated tissue-culture environments, which transitioned from being dominated by a permissive host cell type to a novel host cell type. The rate at which the novel host ‘invaded’ the environment varied by treatment. The fitness (growth rate) of evolved virus populations was measured on each host type, and molecular substitutions were mapped via whole genome consensus sequencing. Results showed that virus populations more consistently reached high fitness levels on the novel host when the...

尽管环境更替速率的差异本应对适应性变化的动态产生重要影响，但这一观点除理论研究外鲜有实证检验。尤其，RNA病毒在疾病涌现中的重要性，亟需开展实验以探究新型宿主入侵速率的差异如何影响病毒向新型宿主适应性转移的能力。为验证环境更替速率是否影响适应性，我们在重复的组织培养环境中对144个辛德毕斯病毒谱系进行了实验进化；该环境从以允许性宿主细胞类型为主，向新型宿主细胞类型转变。新型宿主“入侵”环境的速率因处理方式而异。我们测定了进化后病毒群体在每种宿主类型上的适合度（生长速率），并通过全基因组一致性测序绘制了分子替换图谱。结果表明，当...时，病毒群体在新型宿主上更稳定地达到了高适合度水平。