MS2,f2 and Qβ ssRNA Phages

MS2,f2 and Qβ ssRNA Phages

	MS2,f2 and Qβ ssRNA Phages - The ssRNA coliphages fall into three, or possibly four serological subgroups. The group I ssRNA phages are quite similar to each other and include f2, MS2, R17, M12, fr and FH5. These differ from each other by only a few amino acids. They adsorb only to bacteria carrying the sex factor (P).
The RNA phages are specific for the F pili, and are unable to infect cells carrying I or N pili. On the other hand both Pf and If ssDNA phages have been identified. The Qβ phage is a member of group III, and differs considerably from the f2 group of phages