In ageing research, the key breakthrough will be the elucidation of the molecular pathways that render cells from long-lived animals 鈥� whales, people, bats, porcupines 鈥� resistant to many forms of injury. Studies in worms have shown that mutations that extend lifespan do so by making them resistant not merely to one kind of stress (DNA damage, say, or oxidative injury) but to multiple forms of harm. Biologists are gradually showing that similar protective pathways also slow ageing in flies and mice, and that these cellular circuits date back further than the evolutionary branch point between yeast and us.
Figuring out how this 鈥渋njury protection package鈥� is turned on by evolution in long-lived animals, and by ultra-low-calorie diets and dwarfing mutations in mice, dogs, horses and probably people, will be the key step towards development of authentic anti-ageing pharmaceuticals that turn the same trick. It is now routine, in laboratory mammals, to extend lifespan by about 40 per cent. Turning on the same protective systems in people should, by 2056, be creating the first class of centenarians who are as vigorous and productive as today鈥檚 run-of-the-mill sexagenarians.