The duper mutation reveals previously unsuspected functions of in circadian entrainment and heart disease.

The ()-deficient duper mutant hamster has a short free-running period in constant darkness (τ) and shows large phase shifts in response to brief light pulses. We tested whether this measure of the lability of the circadian phase is a general characteristic of -null animals and whether it indicates resistance to jet lag. Upon advance of the light:dark (LD) cycle, both duper hamsters and mice re-entrained locomotor rhythms three times as fast as wild types.