Coinfection and the Consequences for RNA Virus Evolution

Yale University, New Haven CT

Investigators

Abstract

Most natural infections contain multiple viruses, and this has important consequences for virus evolution. On the one hand, viruses can swap genes during co-infection, creating variability that allows rapid virus evolution. On the other hand, increased competition between viruses can occur during co-infection, slowing the rate of virus evolution. This suggests a compromise where viruses evolve to restrict the numbers that enter a cell (to decrease competition) without reducing the number to one (to achieve gene exchange). Given the widespread occurrence of virus co-infection, it is surprising that the costs and benefits of this phenomenon are virtually unexplored. The focus of this project is to address the question using viruses that infect bacteria. Laboratory experiments will examine the evolution of virus traits that control co-infection numbers, and molecular analyses will determine the genetic changes responsible. The results of this project can be applied to several systems because viruses are important disease agents in animals, plants, and bacteria. Because the life cycle of the project virus is similar to that of many human viruses (such as influenza and HIV), the project data should contribute greatly to a better understanding of the generalized role of virus co-infection in human illnesses.