Circadian rhythm and melatonin · Lab experiment

Why are some mammals awake by day and others by night?

Paper: A cellular basis for the mammalian nocturnal-diurnal switch
Beale et al. · Science 2026 · doi.org/10.1126/science.ady2822

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Why are some mammals awake by day and others by night? Early mammals were nocturnal. In cells from day-active mammals, key processes are less sensitive to temperature than in nocturnal ones. And inhibiting one signalling pathway shifted nocturnal mice toward daytime.

AI-assisted summary with an AI voice, not reviewed by the authors. Made from the paper under its CC BY licence. Read the paper before relying on a finding. Keywords: circadian clock, temperature sensitivity, protein synthesis, protein phosphorylation, mTOR signaling, Cretaceous-Paleogene mass extinction.