The Department of Molecular Biosciences, University of Kansas, Lawrence, United States.
Elife. 2020 Oct 28;9:e58931. doi: 10.7554/eLife.58931.
Hosts and viruses are constantly evolving in response to each other: as a host attempts to suppress a virus, the virus attempts to evade and suppress the host's immune system. Here, we describe the recurrent evolution of a virulent strain of a DNA virus, which infects multiple Drosophila species. Specifically, we identified two distinct viral types that differ 100-fold in viral titer in infected individuals, with similar differences observed in multiple species. Our analysis suggests that one of the viral types recurrently evolved at least four times in the past ~30,000 years, three times in Arizona and once in another geographically distinct species. This recurrent evolution may be facilitated by an effective mutation rate which increases as each prior mutation increases viral titer and effective population size. The higher titer viral type suppresses the host-immune system and an increased virulence compared to the low viral titer type.
当宿主试图抑制病毒时，病毒会试图逃避并抑制宿主的免疫系统。在这里，我们描述了一种感染多种果蝇物种的烈性 DNA 病毒的反复进化。具体来说，我们发现了两种截然不同的病毒类型，它们在感染个体中的病毒滴度相差 100 倍，在多个物种中也观察到了类似的差异。我们的分析表明，其中一种病毒类型在过去的 30000 年中至少反复进化了四次，其中三次发生在亚利桑那州，一次发生在另一个地理上不同的物种中。这种反复进化可能是由一种有效的突变率促成的，这种突变率随着每次先前的突变增加病毒滴度和有效种群大小而增加。与低病毒滴度类型相比，高病毒滴度病毒类型抑制宿主免疫系统并具有更高的毒力。
