Genomic imprinting and the control of sleep in mammals

Recent epigenetic studies suggest that genomic imprinting is crucial in the biology of sleep. Sleep is a physiological process that is governed by homeostatic and circadian mechanisms, and here we review evidence that both mechanisms are influenced by imprinted regulatory processes. A growing number of imprinted genes are being associated to direct and indirect control of sleep, and in some cases, thermoregulation represents an important metabolic component for the interplay between imprinted mechanisms and sleep physiology. Moreover, it is a new striking phenomenon that we discovered that sleep traits follow parent-of origin inheritance. Parental genome is important to the extent that it can determine whether a gene is either homeostatically regulated or not, in response to sleep loss. Therefore, it is now clear that the association between genomic imprinting and sleep exists. However, the experimental work towards the link between sleep and imprinting is just at its early stages, the next years will be pivotal to fully understand whether the genomic imprinting hypothesis of sleep can lead to major discoveries and, perhaps, to unravel the mysteries of sleep.