Chapter 10: Gene Expression and Regulation

Regular exercise and avoiding smoking and alcohol will reduce your risk of heart disease and increase the odds that you’ll live to see your 70s or 80s, but how do you survive to be 100 or older? Restrict your food intake. Mice kept on calorie-restricted diets—20% to 30% fewer calories—live longer than their normal-calorie cagemates. But going through life in a state of near-starvation doesn’t sound like a lot of fun, so what other options exist?

Changing the function of a single gene may be mimicking this near-starvation without the hard work. The partial loss-of-function mutation, Indy, has created a strain of fruit flies (Drosophila melanogaster) that live, on average, twice as long as normal flies. Indy flies develop and reach maturity at the same rate as normal flies, and are just as fertile and produce just as many offspring. However, Indy flies produce offspring for a longer time period, so this mutation doesn’t just permit old flies to live longer, it seems to truly extend the "productive" life span.

Indy, as in "I'm not dead yet" from the movie Monty Python and the Holy Grail, is a mutant form of a gene important for fuel metabolism. The scientists who isolated Indy believe that it slows down metabolism similar to the way calorie-restricted diets slow metabolism. Although we are still a long way from an anti-aging pill, understanding how Indy works to change the rate of metabolism may give us some insight into the relationship of energy production and use and aging.