Help:Plasmid backbones/Features/Antibiotic resistance marker

At the most basic level, function of the antibiotic resistance marker is to allow the cell to grow even in the presence of a particular antibiotic. Plasmid backbones include antibiotic resistance markers because the markers allow you to select for cells that contain your plasmid. When E. coli cells grow and divide, plasmids can inadvertently be lost from the cell. In some cases, cells without a plasmid can potentially grow faster than cells with the plasmid which means that cell cultures can quickly become dominated by plasmid-free cells. Since most BioBrick® parts are maintained on plasmid backbones, plasmid loss is problematic. To help avoid these problems, every plasmid backbone includes an antibiotic resistance marker. Thus, cells which don't have a copy of the plasmid are killed by antibiotic present. Common antibiotic resistance markers in BioBrick® plasmid backbones confer resistance to ampicillin ("Amp" or A), kanamycin ("Kan" or K), chloramphenicol ("Cm" or C) and tetracycline ("Tet" or T).