The Doubletime Homolog Mainly Regulates Independently of Its Effects on the Period Homolog in .

The () heterochronic pathway, which regulates developmental timing, is thought to be an ancestral form of the circadian clock in other organisms. An essential member of this clock is the Period protein whose homolog, , in is an important heterochronic gene. functions as a transcriptional repressor of multiple genes including the conserved and microRNAs.