Many animals, including humans, have internal clocks and
calendars to help them regulate behavior, physiological functions and
biological processes. Although scientists have extensively studied the
timekeeping mechanisms that inform daily functions (circadian rhythms), they
know very little about the timekeeping mechanisms that inform seasonal functions.
New research to be published this week in the online early
edition of the Proceedings of the National Academy of Sciences shows, for the
first time, that this measurement of seasonal time has an epigenetic component.
Epigenetics refers to an alteration in gene expression that occurs without a
change in the sequence of DNA molecules.