BAC ( Bacterial artificial chromosome)

BAC are simply plasmids desigened for the cloing of very segments of DNA. They generally includes selecatable markers such as chloramphenicol resistance (MR), as well as a very replication origin (ori) that maintains the plasmid at one or two copies per cell. DNA framents several hundred base pairs in the lenght are cloned into the BAC vectors. The bacterial used as host for recombinnat BAC have mutation that comprises the structure of the bacteria cell wall, facilitating the uptake of these large DNA molecules.