"What are Marathon Mice?" one might wonder when looking at the title of this essay. Marathon mice are mice that have been genetically engineered with the aim to increase their physical potential. These genetically engineered mice contain an enhanced protein that boots the number of slow twitch muscle fibers. The gene that the scientists altered, codes for a protein named PPAR- delta. This gene is considered to be "a master regulator of numerous genes" (www.sciencedaily.com). When the modified mouse is given "GW50116" (www.hhmi.org) the modified protein is activated. This experiment was conducted by Howard Hughes Medical Institute's investigator Ronald M. Evans in collaboration with several other scientists from Seoul National University in South Korea. Their findings were published on August 24, 2004 (www.sciencedaily.com).
There are many benefits to the engineered gene. The mice that are modified to contain this gene have lower levels of cholesterol, triglyceride, and have less of a chance of having high blood pressure. They also are resistant to weight gain even when fed a diet that causes other mice to become obese. These genetically engineered mice contain many more slow twitch muscle fibers than wild type mice. Slow twitch muscle fibers are fatigue resistant, while fast twitch fibers have lost of power, but not for extended period of time. This helps explain the marathon mice's resistance to weight gain. Slow twitch fibers directly use fat cells for their source of energy. Fast twitch fibers use glucose. The increase of slow twitch fibers was a surprise to the research scientists, "We thought that the enhanced PPAR-delta would just enable the muscle to bur more fat, but we didn't expect it would do so by increasing the population of slow twitch fibers," Evens.
There are many statistical differences between marathon mice and regular mice. Marathon mice can "run 1800meters and for 150minutes, while being resistant to weight gain and have lower levels of intramuscular triglycerides"(www.bbc.com). This is in contrast with the wild type of mouse which can run "900 meters, but for only 90 minutes" (Fox). With these obvious benefits, the potential for athletes to have an unfair advantage is a valid concern. If the use of using these findings becomes legal, the global sports arena we know today will be permanently altered. Another potential benefit humans will be able to gain from the modified protein in marathon mice is to receive the benefits of exercise without exercising. This could be used for people who are bed bound or are unable to exercise. It could potentially reduce cholesterol, triglycerides, high blood pressure, and excess weight in patients as well.
PPAR is an acronym that represents peroxisome proliferateor activated receptor. These receptors control how the body processes fat and sugar. There are four main types of PPAR: beta, alpha, gamma, and delta. The PPAR modified in the marathon mice is the delta type protein. PPAR- Beta "increases muscle mass and amount of fat being burned" (Harper). PPAR -- Alpha "lowers fat and cholesterol in the blood stream" (Harper), while PPAR-Gama "controls how cells use insulin to lower blood sugar"(Harper). Lastly, PPAR-Delta "plays a crucial role in heart disease"(Harper).
Because of the growing number of obese people throughout the world, I think that this modified protein could be a truly essential aspect of modern medicine. The protein and drug used to engineer Marathon Mice could vastly reduce the number of heart attacks and other heart problems. "These drugs… might help stave the toll of cardiovascular disease, the No. 1 killer in the developed world" (Harper). This is a realistic goal too. When the drug was given to mice that had not been genetically engineered, they wreaked the same benefits as the genetically engineered mice.