The term Jet lag comprises a range of psycho- and physiopathological symptoms that arise from temporal misalignment of the endogenous circadian clock with external time. Repeated jet lag exposure, encountered by business travelers and airline personnel as well as shift workers, has been correlated with immune deficiency, mood disorders, elevated cancer risk and anatomical anomalies of the forebrain. Here we characterized the molecular response of the murine circadian system in an established experimental paradigm for jet lag. Unexpectedly, strong heterogeneity of entrainment kinetics was...