We have generated a life-extending mutation,
yw23, tl Caenorhabditis elegans The mutation is in what appears to be a new aging gene, which we have designated
age-2. When homozygous,
yw23 produces an increase of mean and maximum life span of about 20% over that of the wild-type strain, N2. Strain HG23 [
age-2(
yw23)] was obtained by screening for longer life spans among 430 lines of nematodes two generations after exposure to the mutagen ethylmethanesulfonate. Strain HG231 [
age-2(
yw23)] was obtained after a single oat-crossing of HG23 to NZ. When compared with N2, HG231 exhibits normal motility, slightly higher swimming rates, reduced fertility (especially at higher temperatures), somewhat longer development times, and a slightly larger size at the time of first egg laying. A Gompertz analysis suggests that HG231 extends life span by reducing the initial mortality rate. In generic crosses,
yw23 complements other known aging mutants in C. elegans genes-
age-1,
daf-2,
spe-26,
clk-1,
clk-2,
clk-3, and
gro-1. A double-mutant strain, HG284, combining mutations in
age-1 and
age-2, fires longer than animals with individual mutations in either
age-1 or
age-2, and exhibits a longer life span at 25 degrees C than at 20 degrees C.