Biological clocks

Circadian rhythms describe biological phenomena that oscillate with an appr oximate to 24-hour cycle. These rhythms include blood pressure, body temper ature, hormone levels, the number of immune cells in blood, and the sleep-w ake cycle, In this paper, we will focus on common genes between species tha t are responsible for determining the circadian behavior, especially some t ranscription factors (i.e., switch genes) that serve to regulate many circa dian rhythm genes. The intent of this summary is to introduce the common mo lecular mechanism of biological clocks between flies and humans and then to describe the research from three laboratories that was presented in the se ssion.