[Sleep genes].

INTRODUCTION: Sleep is a non-learned adaptive strategy that depends on the expression of several neurotransmitters and other molecules. The expression of some of these molecules depends on a number of different genes. Sleep disorders are associated with an inadequate expression of some molecules, which therefore indicates that these genes that code for these molecules participate in the regulation of normal sleep.

AIM: To discuss the evidence on gene regulation over the occurrence of sleep and its architecture, as well as of sleep disorders, which supports the participation of specific genes.

DEVELOPMENT: We describe the evidence on sleep in mammals, particularly in humans, in addition to studies with twins that demonstrate the influence of genes on sleep regulation. We also discuss several sleep disorders, which in this study only serves to emphasise how certain specific genes, under normal conditions, participate in the expression of sleep. Furthermore, evidence is also provided for other molecules, such as endocannibinoids, involved in sleep regulation. Lastly, we report on studies conducted with different strains of mice that show differences in the amount of sleep they express, possibly as an epiphenomenon of their different genetic loads.

CONCLUSIONS: A number of different genes have been described as those responsible for making us sleep, although sleeping also depends on our interaction with the environment. This interaction is what makes us express sleep at times that are best suited to favouring our survival.