Viva the worm

Like yin and yang, good things usually come at a cost. If you live longer, then you give up reproductive fitness in return. The merits of this model—termed antagonistic pleiotropy—have been argued by evolutionary biologists for half a century. Some believe that the effort of reproduction is necessarily linked to deterioration characteristic of aging. But now Andrew Dillin (Salk Institute for Biological Studies, La Jolla, CA), Douglas Crawford, and Cynthia Kenyon (University of California, San Francisco, CA) have challenged the idea by uncoupling reproduction and aging.

They focused their studies on worms, in which the insulin pathway controls both reproduction and aging. Mutations in the DAF-2 insulin-like receptor prolong the lifespan of a worm, but reduce its fertility. The new data indicate that...