Daniel Forger, an NYU biologist and mathematician, and Charles Peskin, a professor at NYU's Courant Institute of Mathematical Sciences and Center for Neural Science, developed a mathematical model of the biological clock that replicates the hundreds of clock-related molecular reactions that occur within each mammalian cell.
Biological circadian clocks time daily events with remarkable accuracy--often within a minute each day. However, understanding how circadian clocks function has proven challenging to researchers. This is partly because the 24-hour rhythm is an emergent property of a complex network of many molecular interactions within a cell. Another complication is that molecular interactions are inherently random, which raises the question how a clock with such imprecise components can keep time so precisely. One way to combat molecular noise is to have large numbers of molecular interactions, but this is limited by the small numbers of molecules of some molecular species within the cell (for instance, there are only two copies of DNA).
To simulate the random nature of the biochemical interactions of the mammalian intra-cellular circadian clock, Forger and Peskin used the existing Gillespie method. The method tracks the changes in the integer numbers of each type of molecule of the system as these biochemical reactions occur. Modeling each type of molecule separately helped avoid mathematical assumptions in their model that may not be valid in real-life cells. Their mo
Contact: James Devitt
New York University