Aging: A Biological Perspective
A variety of techniques extend the lives of model organisms, and similar approaches might help human beings stay healthy longer
People spend more time trying to avoid aging than trying to understand it. We deny aging at first and then—seeing its reality in the mirror—grudgingly accept it. For some reason, the biology of aging attracted my attention early on, during my graduate-student days. At that time, most other scientists regarded the study of aging as a somewhat misdirected and not quite respectable activity, and so I studied other topics. In the past two decades, though, biological investigations of aging grew into cutting-edge science. Unfortunately, little of that intellectual excitement reaches the larger society.
I realized the complicated job of explaining the biology of aging after one conversation with my mother-in-law, who was a pragmatic country woman, well rooted in her time and place. She had apparently made her peace with the fact that one of her sons-in-law made his living by playing around with flies. But in 1979, I told her that I was changing my research focus from studying fly development to studying how to make flies live longer. She looked at me for a long minute with an expression that told me she was reconsidering her daughter's taste in men. Finally, she leaned over and said to me in a very tolerant way, "Bob, we don't want flies to live longer." I had no good reply at the time, but today I could tell her in exhaustive detail that she was partly wrong. We do want flies to live longer, at least in the laboratory, for only then will we be able to make ourselves live longer, too.
As we learn more about aging, we will think more deeply about the consequences of our increasing ability to alter this biological process. To provide an overview of this field, this article defines aging in modern biological terms, describes our current understanding of the biological mechanisms that underlie aging, reviews successful cases of longevity intervention in laboratory animals and discusses the implications for humans. Taken together, this information makes an intriguing tale.