Exploration of Genes Responsible for Host-range Expansion

Viruses are often thought to be very selective in the hosts they can infect – a virus that infects one species often cannot infect a different species. We know however, that sometimes they can make such evolutionary leaps and infect additional hosts. Occasionally this occurs with devastating impacts such as with the Ebola or Corona viruses. The process by which viruses make these jumps can be safely studied in the laboratory by using bacteriophages, viruses that infect bacteria. We have identified two bacteriophages that are nearly 96% identical in their DNA yet differ in their abilities to infect the host Rhodobacter capsulatus B10. To determine the region of DNA responsible for this expanded host range, we have examined varying regions in their genomes and copy these segments from the bacteriophage that can infect B10 to the one that cannot. Because previous work focusing on larger areas of variability between these two was not able to uncover the region involved in this process, recent efforts have focused on the less variable tail protein genes involved in directly interfacing with the host cell. Understanding this process may allow for the creation of therapeutic viruses that infect multiple harmful bacteria strains