Prior to the development of cycle sequencing, phagemids were used to generate single stranded DNA template for sequencing purposes. Today phagemids are still useful for generating templates for site-directed mutagenesis. Detailed characterisation of the filamentous phage life cycle and structural features lead to the development of phage display technology, in which a range of peptides and proteins can be expressed as fusions to phage coat proteins and displayed on the viral surface. The displayed peptides and polypeptides are associated with the corresponding coding DNA within the phage particle and so this technique lends itself to the study of protein-protein interactions and other ligand/receptor combinations. References Cloning Molecular biology