A bacterial artificial chromosome (BAC) ia a vector with a
large cloning capacity (up to 300 kb).
A BAC is constructed from a fertility plasmid (F factor) that enables conjugation.
A chloramphenicol resistance gene serves to screen for recombinants, while a polylinker contains several restriction enzyme recognition sites for inserting foreign DNA.
Promoter regions at T7 and Sp6 allow expression of inserted genes.