Scientific American has a lengthy article that goes into detail about unlocking the secrets of longevity genes:
A handful of genes that control the body's defenses during hard times can also dramatically improve health and prolong life in diverse organisms. Understanding how they work may reveal the keys to extending human life span while banishing diseases of old age.
And in the longer term, we expect that unlocking the secrets of longevity genes will allow society to go beyond treating illnesses associated with aging and prevent them from arising in the first place. It may seem hard to imagine what life will be like when people are able to feel youthful and live relatively free of today's diseases well into their 90s. Some may wonder whether tinkering with human life span is even a good idea. But at the beginning of the 20th century, life expectancy at birth was around 45 years. It has risen to about 75 thanks to the advent of antibiotics and public health measures that allow people to survive or avoid infectious diseases. Society adapted to that dramatic change in average longevity, and few people would want to return to life without those advances. No doubt, future generations accustomed to living past 100 will also look back at our current approaches to improving health as primitive relics of a bygone era.
Before you ask yourself whether tinkering with our biology, ask yourself if you'd like to back in time a hundred or two hundred years.
As Ray Kurzweil writes in one of his books... We didn't stick to land. Instead we went sailing and flying, and even travelled into outer space. We won't stick with our biology. Going past our own limits is part of what defines us as humans.
(inaccurately quoted from memory, but the essence is correct)
Anybody interested in detailed talk about longevity related genes, should definately read the source article.