Characterizing a 12 hour biological clock.
Physiology A mathematical analysis of changes in gene expression in mouse liver, designed to detect oscillations of various frequencies, showed more than 3500 genes whose expression cycled with a 12 hour period. This is distinct from circadian gene expression, which is coupled to the 24 hour light cycle, and has been noted before in marine animals, perhaps because of a need to synch with 12 hour tidal changes. Zhu et al. found that gene products associated with 12 hour cycles are particularly related to metabolic function, endoplasmic reticulum stress, and the unfolded protein response. The 12 hour clock appears to be distinct from the well known circadian oscillator and was evident in nematodes and crustaceans, as well as mammals. Cell Metab. 10.1016/j.cmet.2017.05.004 (2017)
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