- Gabriel Wu 17:30, 4 March 2013 (EST): On a practical note, ampicillin (amp), kanamycin (kan), and chloramphenicol (cam) are the most used antibiotic selection markers in synthetic biology. Amp in my experience is convenient, but somewhat "fragile" (relative to kan and cam). Convenient: typically "rescuing" your cells post-transformation is unnecessary when using amp. "Rescuing" is necessary for kan and cam. Cam and kan are useful for long time course experiments (longer than 24 hours) because amp generally breaks down (or is broken down) over time.