 The artificial repressilator is a milestone of synthetic biology which shows that genetic regulatory networks can be designed and implemented to perform novel functions.However, it was found that the cells' oscillations drifted out of phase after a period of time and the artificial repressilator's activity was influenced by cell growth.The initial experiment therefore gave new appreciation to the circadian clock found in many organisms, as endogenous repressilators are significantly more robust than implanted artificial repressilators.