"It's an elaborate, very pretty dance, but it's absolutely critical because when this goes wrong, that's what cancer is all about, right? The cell division cycle isn't working right, you get cancer," Harer said.
The circadian clock, which is largely impacted by light and darkness, has similar mechanisms. Together, the biological clocks present a challenge - a mathematical one - to scientists trying to create models of what is happening and how the various systems work together.
"That's where you get to the possibility of explaining things, like why is it that people who have bad sleep patterns maybe are more likely to get certain kinds of diseases, like cancer," Harer said. "Maybe there's a coupling between the circadian clocks and the cell-cycle clocks. Or why is it that people who have sleep problems, also have metabolism problems?"
Accurate models would, in turn, guide the work of biologists looking for ways to restore, repair or enhance biological clocks.
DARPA says that could be key to helping soldiers in battle, improving trauma care and unraveling mechanisms of and treatments for disease.