A phagemid or phasmid is a plasmid that contains an f1 origin of replication from an f1 phage. It can be used as a type of cloning vector in combination with filamentous phage M13. A phagemid can be replicated as a plasmid, and also be packaged as single stranded DNA in viral particles. Phagemids contain an origin of replication (ori) for double stranded replication, as well as an f1 ori to enable single stranded replication and packaging into phage particles. Many commonly used plasmids contain an f1 ori and are thus phagemids. Similarly to a plasmid, a phagemid can be used to clone DNA fragments and be introduced into a bacterial host by a range of techniques, such as transformation and electroporation. However, infection of a bacterial host containing a phagemid with a 'helper' phage, f