Mutations or deletions of clock gene in mice have demonstrated the importance of body clocks to ensure the proper timing of cellular/metabolic events; clock-mutant mice are hyperphagic and obese, and have altered glucose metabolism. In mice, deletion of the Rev-ErbA alpha clock gene facilitates diet-induced obesity and changes the balance between glucose and lipid utilization predisposing to diabetes. However, it is not clear whether there is a strong association between clock gene polymorphisms in humans and the susceptibility to develop the metabolic syndrome.
What is the body clock gene in animals necessary to ensure? What do mice without the clock gene become? Beside obesity, how else does the lack of a circadian clock effect   the mice? How certain is it that these circadian clock  effects are the same in humans? What gene needs to be deleted to cause obesity in mice?