[
1990]
Caenorhabditis elegans is a short-lived species that has been widely used in the genetic dissection of development. This species is becoming important in the genetic analysis of aging because strains with mean life spans more than 70% longer than wild type have been identified both through the use of recombinant inbred lines and by the induction of single-gene mutants. Its unique hermaphroditic mode of reproduction leads to a lack of inbreeding depression and simplifies genetic analyses of quantitative traits such as length of life or behavior. Aging in this organism is composed of at least three independent processes: that specifying length of life, that specifying reproductive senescence, and that specifying senescence of the general motor system. These data suggest that aging is not a unitary process but that many different processes or independent components may be involved in various aspects of aging. Most importantly, an apparent single-gene mutation has been mapped to the middle of linkage group II; this mutation lengthens mean and maximum life span 60-110% and also decreases fertility about five-fold.