IS LIFE SPAN IN C. ELEGANS DETERMINED BY A BIOLOGICAL CLOCK OR BY A CASCADE?
Pamela L. Larsen [1, 2], Mark Sundermeyer [1] and Donald L. Riddle [1] [1] Division of Biological Sciences, University of Missouri, Columbia, MO 65211 [2] Andrus Gerontology Center, University of Southern California, Los Angeles CA 90089-0191 Mutations in the daf-2 and daf-23 genes double adult life span, whereas mutations in four other dauer-constitutive genes positioned in a separate branch of the dauer larva formation pathway (daf-1, daf-4, daf-7 and daf-8) do not. Increased life spans of daf-2, daf-23, and age-1 are suppressed completely by a daf-16 mutation and partially in a daf-2; daf-18 double mutant. A genetic pathway for determination of adult life span will be presented. The adult life span is affected in daf-2; daf-12 double mutants in an allele-specific manner. Mutations in daf-12 do not extend adult life span, but certain combinations of daf-2 and daf-12 mutant alleles nearly quadruple it. This is the largest genetic extension of life span yet observed in a metazoan. The
