Clock Gene, Melatonin, and the Sleep–Wake Cycle

The review examines the role of the Clock gene and melatonin as participants in human circadian rhythms. The results of studies on the association of the Clock gene polymorphisms and the sleep–wake cycle, as well as circadian rhythms of melatonin secretion in different chronotypes and insomnia, are presented. A hypothesis about the role of the Clock 3111T/C gene polymorphism in the formation of insomnia in Caucasian women living in Eastern Siberia is considered.