Fruit flies and life spans: how long do they live?
Widely used in fundamental genetic research because of their short life spans, relatively simple chromosomal structure, and the fact that their entire genome has been mapped since 1998, research by Dr Michael Rose, an evolutionary biologist at the University of California at Irvine, fruit flies can have their lifespans extended many times over by accelerating the process of evolution in the laboratory. The process is relatively simple: evolution will allow a species to live as long as it can reproduce, so extending the life span of fruit flies means denying them the ability to reproduce until later in their lives. Fruit flies that reproduce, and thereby contribute to the continuation of the species, have fulfilled their evolutionary "role" and evolution will not select for genes that allow the organism to live past that point.
This is how his experiments worked: his researchers would discard eggs laid by females until day 50 of their lifecycle. If they were still alive (fruit flies' typical life span is about 2 weeks) and still able to reproduce, then that would suggest they have some sort of genetic mutation allowing them to live longer. They would reproduce and leave their long-life genes to their children. Subsequent selections would leave a large pool of flies with the ability to live much longer than the typical 14 days or so, because, if they didn't, they would have become extinct.
What does this mean for us? After all, we have to make do with the genes we have. Dr Rose's research says that evolution is generally only concerned with keeping us healthy until the point that we reproduce-after that, we're on our own. Evolution has no interest in making sure we live longer or shorter after that. The processes by which we age and deny do not fit one general pattern or predestination. As Dr Rose says, "Aging isn't some general breakdown process, like the way cars rust. Aging is an optional feature of life. And it can be slowed or postponed."
Going on, Dr Rose argues that evolutionary biology teaches us that postponing aging does not violate basic scientific laws. Things we do can extend-or shorten-our life spans. However, he argues there is no one "magic bullet" that will do the trick. The more that science discovers and proves, the more we can incorporate into our lives and increase our life span one step at a time.
We know now, rather conclusively, that regular exercise extends our lives. So does a healthy, balanced diet. These may seem obvious now, but they were not widely known or understood even 50 years ago. The same goes for supplementation, which Dr Rose argues in his new book, The Long Tomorrow : How Advances in Evolutionary Biology Can Help Us Postpone Aging, have the capacity to incrementally add years to our lives, as new discoveries of nutritional and pharmaceutical therapies become available.