Biological Clocks Animations
Biological Clocks: Animations (Howard Hughes Medical Institute)
From the 2000 Holiday Lectures — Clockwork Genes: Discoveries in Biological Time
The existence of biological clocks has been suspected for centuries, but for most of human history little was known about how they worked. In the last few decades — with enormous advances in molecular biology and genetics — the detailed chemical workings of biological clocks have begun to be understood. This exhibit explores the inputs, outputs, and mechanisms of biological clocks with a primary focus on circadian rhythms—circadian being a term that biologists use to describe biological mechanisms on the scale of a day, from the Latin meaning "about a day."
The Drosophila Molecular Clock Model (Howard Hughes Medical Institute)
Watch these animations display the dynamic orchestration of the molecular events of the Drosophila biological clock.
The Human Suprachiasmatic Nucleus (Howard Hughes Medical Institute)
In mammals, the controlling clock component that generates a 24-hour rhythm is the suprachiasmatic nucleus (SCN), located in a part of the brain called the hypothalamus. The SCN produces a signal that can keep the rest of the body on an approximately 24-hour schedule. This animation illustrates the location of the SCN in the human brain.
The Mammalian Molecular Clock Model (Howard Hughes Medical Institute)
This animation shows the molecular interactions involved in the negative feedback loop responsible for circadian rhythms in mammals.
Measuring Circadian Activity in Drosophila (Howard Hughes Medical Institute)
This animation series shows four experiments that compare the activity patterns of a wild-type fly keeping a normal schedule with those of a mutant fly apparently following a 19-hour internal clock.