The term "clock gene" refers to any of the numerous genes that play a role in the regulation of circadian rhythms or the internal timing system of living organisms. Synonymous terms for clock gene include circadian gene, biological clock gene, and rhythm gene. These genes help control various aspects of behavior, physiology, and metabolism as well as sleep and wake cycles. The study of these genes has significant implications in healthcare as well as agriculture, since many crops exhibit daily rhythms that determine their growth and development patterns. Researchers continue to explore the mechanisms involved in clock gene function to better understand how it affects health and disease.