CLOCK and diabetes mellitus: Indeed, genetic ablation of the circadian clock in different tissues can lead to divergent pathologies, such as diabetes in pancreas-specific Bmal1 knockout (KO) and fasting hypoglycemia in liver-specific Bmal1 KO, suggesting that the clock interweaves with tissue-specific transcriptional programs (Bass and Lazar 2016), but how diurnal and tissue-dependent regulatory landscapes interact to generate tissue-specific rhythms is poorly understood.