Grubaugh Nathan D, Rückert Claudia, Armstrong Philip M, Bransfield Angela, Anderson John F, Ebel Gregory D, Brackney Doug E
Department of Microbiology Immunology and Pathology, College of Veterinary Medicine and Biomedical Sciences, Fort Collins, CO, USA.
The Connecticut Agricultural Experiment Station, Center for Vector Biology and Zoonotic Diseases, New Haven, CT, USA.
Virus Evol. 2016 Oct 26;2(2):vew033. doi: 10.1093/ve/vew033. eCollection 2016 Jul.
Arthropod-borne RNA viruses exist within hosts as heterogeneous populations of viral variants and, as a result, possess great genetic plasticity. Understanding the micro-evolutionary forces shaping these viruses can provide insights into how they emerge, adapt, and persist in new and changing ecological niches. While considerable attention has been directed toward studying the population dynamics of mosquito-borne viruses, little is known about tick-borne virus populations. Therefore, using a mouse and tick transmission model, we examined Powassan virus (POWV; ) populations in and between both the vertebrate host and arthropod vector. We found that genetic bottlenecks, RNAi-mediated diversification, and selective constraints collectively influence POWV evolution. Together, our data provide a mechanistic explanation for the slow, long-term evolutionary trends of POWV, and suggest that all arthropod-borne viruses encounter similar selective pressures at the molecular level (i.e. RNAi), yet evolve much differently due to their unique rates and modes of transmission.
节肢动物传播的RNA病毒在宿主内以病毒变体的异质群体形式存在，因此具有很大的遗传可塑性。了解塑造这些病毒的微观进化力量可以深入了解它们如何在新的和不断变化的生态位中出现、适应和持续存在。虽然人们对研究蚊媒病毒的种群动态给予了相当多的关注，但对蜱传病毒种群却知之甚少。因此，我们使用小鼠和蜱传播模型，研究了脊椎动物宿主和节肢动物媒介体内及之间的波瓦桑病毒（POWV）种群。我们发现，遗传瓶颈、RNAi介导的多样化和选择性限制共同影响POWV的进化。总之，我们的数据为POWV缓慢的长期进化趋势提供了一个机制性解释，并表明所有节肢动物传播的病毒在分子水平上（即RNAi）都面临类似的选择压力，但由于它们独特的传播速率和模式，进化方式却大不相同。
