Circadian clock genes, role

Zheng B, Albrecht U, Kaasik K et al 2001 Nonredundant roles of the mPerl and mPer2 genes in the mammalian circadian clock. Cell 105 683-694... 

Circadian clocks are molecular time-keeping mechanisms found in a broad range of cell types from a variety of organisms. The primary roles of these clocks are to maintain their own 24 hour molecular rhythm and to drive the rhythmic expression of genes that control output processes in physiology, metabohsm and behaviour. Core features of the clock are its ability to synchronize to daily environmental speitgehers (e.g. hght—dark or temperature cycles), and then maintain rhythmic function when placed in constant conditions. 

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