TheDrosophila circadian clock
The circadian rhythm in the process of eclosion of the fruitflyDrosophila is the best investigated with regards to properties such as entrainment, freerun and phase shifts. The system has been the basis of an important coupled oscillator model, several hypotheses, landmark papers and a monograph. ThePRC for this rhythm has been extensively used in experiments designed to test the kinetics of the basic clock. The singularity point, signifying a stimulus that can ’stop’ the clock, was also predicted and discovered in this rhythm. Fittingly the first clock mutant was also discovered inDrosophila.