Mutant Clouds and Bottleneck Events in Plant Virus Evolution

Plant viruses can develop high levels of variation in their populations, but this is not always the case. The level of diversity in single plant infections varies dramatically with different viruses and different hosts. Recent studies on diversity in the DNA geminivurses indicate that they have variation levels that are comparable to RNA viruses, in spite of their replication by the host DNA polymerase. Genetic bottlenecks occur during systemic infection of plant viruses and transmission events. Bottlenecks can have important effects on plant virus evolution due to genetic drift, and can ultimately result in isolation and evolution of new variants and speciation events.