A mutation in the age-1 gene in Caenorhabditis elegans lengthens life and reduces hermaphrodite fertility
Friedman, D.B.; Johnson, T.E.
Genetics 118(1): 75-86
1988
ISSN/ISBN: 0016-6731 PMID: 8608934 Document Number: 311229
Age-1(hx546) is a recessive mutant allele in C. elegans that results in an increase in mean lifespan averaging 40% and in maximal lifespan averaging 60% at 20 degrees C; at 25 degrees C age-1(hx546) averages a 65% increase in mean lifespan (25.3 days vs. 15.0 days) and a 110% increase in maximum lifespan (46.2 days vs. 22.0 days for wild-type hermaphrodites). Mutant males also show extended lifespans. Age-1(hx546) is associated with a 75% decrease in hermaphrodite self-fertility as compared to the age-1+ allele at 20 degrees C. Using 2 novel strategies for following the segregation of age-1, evidence is presented to show that longer life results from a mutation in a single gene that increases the probability of survival at all chronological ages. The long-life and reduced-fertility phenotypes cosegregate and are tightly linked to fer-15, a locus on linkage group II. Age-1(hx546) did not affect the timing of larval moults, the length of embryogenesis, food uptake, movement or behaviour. Although age-1(hx546) lowered hermaphrodite self-fertility, it did not markedly affect the length of the reproductive period with all the increase in life expectancy due to an increase in the length of postreproductive life. This mutant in age-1 is the only known instance of a well-characterized genetic locus in which the mutant form results in lengthened life. It is likely that the action of age-1 in lengthening life results not from eliminating a programmed aging function, but rather from reduced hermaphrodite self-fertility or from some other unknown metabolic or physiologic alteration.