Neisseria species are known to undergo both phase and antigenic variation. Define phase versus antigenic variation and describe how each might occur. What advantage do they provide for a pathogen?...

Neisseria species are known to undergo both phase and antigenic variation. Define phase versus antigenic variation and describe how each might occur. What advantage do they provide for a pathogen?

Some researchers have tried to identify the PAIs in Salmonella by comparing the E. coli K-12 genome with that of S. enterica serovar Typhimurium. What are the advantages and disadvantages of this approach?