MORTALITY-RATES IN A GENETICALLY HETEROGENEOUS POPULATION OF CAENORHABDITIS-ELEGANS

Age-specific mortality rates in isogenic populations of the nematode C aenorhabditis elegans increase exponentially throughout life. In genet ically heterogeneous populations, age-specific mortality increases exp onentially until about 17 days and then remains constant until the las t death occurs at about 60 days. This period of constant age-specific mortality results from genetic heterogeneity. Subpopulations differ in mean life-span, but they all exhibit near exponential, albeit differe nt, rates of increase in age-specific mortality. Thus, much of the obs erved heterogeneity in mortality rates later in life could result from genetic heterogeneity and not from an inherent effect of aging.