Researchers at Case Western University have genetically-altered mice to make a remarkable alteration in energy metabolism due to the over-expression of the gene for the enzyme phosphoenolypyruvate carboxykinases (PEPCK-C).
These genetically engineered mice also eat 60 percent more than controls, but remain fitter, trimmer and live and breed longer than wild mice in a control group. Some female PEPCK-C mice have had offspring at 2.5 years of age, an amazing feat considering most mice do not reproduce after they are one year old … The PEPCK-C mice ran an average of 31.9 minutes, compared to 19 minutes for the control animals.
The PEPCK-C mouse ran six kilometres at 20 metres per minute. You can watch a video at Skycast and I recommend you do – they play the Rocky theme tune and it’s awesome.
ADDENDUM: Story from BBC.