The pBC vectors were derived from the pBluescript II phagemid. The ampicillin-resistance gene has been replaced with the chloramphenicol resistance gene. pBC phagemids (plasmids with a phage origin) are cloning vectors designed to simplify commonly used cloning and sequencing procedures, including the construction of nested deletions for DNA sequencing, generation of RNA transcripts in vitro and site-specific mutagenesis and gene mapping. Convenient selection when subcloning from ampicillin-resistant cloning vectors. With a large and versatile polylinker in Sac-->Kpn orientation and f1 origin in either (-) orientation.