Living Longer

TIME magazine for February 23 / March 2 focused on longevity. (Unfortunately, their website doesn't allow non-subscribers to read entire articles, only short teasers.) The caption on the cover proclaims, "This baby could live to be 142 years old." They base that estimate on an experiment with mice; an antibiotic called rapamycin extends the lifespan of a mouse by about 20 percent. The longer-lived mice suffered some undesirable side effects, though, such as an increased tendency to develop cataracts and diabetes (not to mention loss of testicular function in males—begins to sound like the immortals in the third book of GULLIVER'S TRAVELS, who don't die but keep aging). So the hyped-up headline on the front of the magazine proves to be a bit misleading. We have a long way to go for an elixir of youth and immortality. The article itself, however, does contain interesting information about how cell division and growth relate to aging, such as an explanation of telomeres, "the timekeepers of a cell's life." Other articles in the issue expound on such topics as the best locations for old people to live in, which parts of the body typically wear out at what ages and how we can delay those effects, and how brain exercise and the right attitudes help to keep people "young."

The articles, or at least the headlines, seem to conflate two different things: Enabling more people to survive in good health to the human maximum age of a bit over 100 and extending the maximum lifespan. The former seems more likely than the latter. In Heinlein's METHUSELAH'S CHILDREN, TIME ENOUGH FOR LOVE, and TO SAIL BEYOND THE SUNSET, the Howard Family project extends human life by breeding together people with genes for longevity in their family trees. But, contrary to what the first book seems to assume, it doesn't appear likely that this method would produce offspring with super-long lives. To select for an age span of 150 years, human DNA would have to include genes for living to the age of 150. We've seen no evidence of such genes. In Heinlein's series, Lazarus Long is an exception. He carries a unique mutation that allows him to live a phenomenally long time before needing rejuvenation treatments. And, as you may recall from the novels, even Howards eventually die of old age unless they get those treatments—which ordinary Earth-human scientists developed because they imagined the Howards were hoarding the "secret" of longevity and tried to duplicate it.

Margaret L. Carter

Carter's Crypt