Monday, June 28, 2010

the youth pill

The Scientist | No scientific advances inspire more media hype than ones in gerontology, the study of aging. Even the crustiest editors have been known to turn giddy when new Justify Fulllight is shed on the topic and take to blowing raspberries at the Reaper with headlines suggesting immortality elixirs are just around the corner.

Biologists aren't so easily wowed, though, and before the mid-1990s they generally saw gerontology as a dismal bog where once-promising peers sank out of sight, or worse, re-emerged clutching beakers of snake oil. Compelling logic underlay the dismissiveness: Natural selection has sculpted our genes to care about getting to the next generation, not about keeping our bodies youthful for a long time. Thus, soon after we reach reproductive age, our genes' preservative influence fades, and escalating random damage sets in. Studying the details of this inexorable, chaotic decay seemed a waste of time to most life scientists. And attempting to block or slow it seemed utterly quixotic. In 1957, evolutionary biologist George Williams encapsulated the conventional wisdom by equating the anti-aging quest to the hunt for perpetual motion.

Then in 1988 a miracle happened -- the University of Colorado's Thomas Johnson reported that a gene mutation in nematodes could more than double their life spans. Five years later, Cynthia Kenyon at the University of California, San Francisco, nailed a similar worm "gerontogene" dubbed daf-2. These flabbergasting discoveries revealed that not everything about aging is intractable chaos -- worms, at least, apparently possessed gene-encoded modules poised to oppose the ravages of advancing age when activated by a single mutation. Optimists soon speculated that similar modules exist in mammals.

But for several years after the discovery of worm gerontogenes, it wasn't at all clear that mammals possess such modules. After all, daf-2 and related genes were known to work by activating a semblance of the "dauer phase," a kind of suspended animation that enables nematode larvae to ride out food shortages, and there's a lack of evidence that we warm-blooded types similarly turn into living mummies when the larder is bare. But then two remarkably persistent scientists settled the burning issue -- and solved a murine murder mystery in the process.