Datensatz

Zusammenfassung

Characterizing how viruses evolve expands our understanding of the underlying fundamental processes, such as mutation, selectionand drift. One group of viruses whose evolution has not yet been extensively studied is thePhycodnaviridae, a globally abundant familyof aquatic large double-stranded (ds) DNA viruses. Here we studied the evolutionary change ofParamecium bursariachlorella virus 1during experimental coevolution with its algal host. We used pooled genome sequencing of six independently evolved populations tocharacterize genomic change over five time points. Across six experimental replicates involving either strong or weak demographicfluctuations, we found single nucleotide polymorphisms (SNPs) at sixty-seven sites. The occurrence of genetic variants was highlyrepeatable, with just two of the SNPs found in only a single experimental replicate. Three genesA122/123R, A140/145RandA540Lshowed an excess of variable sites, providing new information about potential targets of selection duringChlorella–Chlorovirus coevo-lution. Our data indicated that the studied populations were not mutation-limited and experienced strong positive selection. Ourinvestigation highlighted relevant processes governing the evolution of aquatic large dsDNA viruses, which ultimately contributes to abetter understanding of the functioning of natural aquatic ecosystems.