Worm Breeder's Gazette 10(2): 37

These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.

Long Life and Low Fertility: Mating Effects on Life Span

Norma Foltz, Tom Johnson and Jo Ellen Shoemaker

Mutations in the age-1 gene effect substantial (age-1 mutants live 
40% longer than N2 at 20 C) extensions in life span (Friedman and 
Johnson, 1988, Genetics 118:7586).  Because age-1 hermaphrodites also 
have reduced fertility (at 20 C, age-1 hermaphrodites produce about 50 
self progeny), we are performing a series of mating experiments to 
find out if life extension in age-1 mutants directly results from low 
We have measured progeny production and life span in virgin and 
mated TJ412 [age-1;fer-15(b26ts)] hermaphrodites to determine if mean 
life span is reduced when mean progeny production is increased.  
Individual hermaphrodites were cultured first on agar to measure 
fertility, and then from 8 days until death in liquid microtiter wells 
to measure life span.
Mean progeny production was increased five- to ten-fold in age-1 
hermaphrodite by wild type (N2) male crosses.  All trials showed 
significantly lower (P values 0.04, 0.002, <0.001) mean life span for 
age-1 hermaphrodites when mated to N2 males.  Life spans for mated 
groups were 22, 14, and 16 days, respectively, compared to 31, 22, and 
28 days for virgin age-1 hermaphrodites.  In these experiments, age-1 
hermaphrodites mated to N2 males had life spans indistinguishable from 
Mated and virgin N2 hermaphrodites were compared to determine if 
mating itself has an effect on life span.  N2 by N2 crosses increased 
total progeny about two-fold, but did not change life span of 
hermaphrodites in two trials.  Mated N2 also showed significantly 
lowered life span in one trial.
In one trial, TJ412 by TJ412 crosses increased total progeny more 
than three-fold and showed life span reduction (28 days for unmated; 
25 days for mated) that was marginally significant (P value 0.05).  
TJ412 hermaphrodites mated by TJ412 males were significantly (P = 0.01)
longer lived than N2 virgins (21 days).
We are currently repeating the experiments with TJ412 and N2 males 
to find out if the apparent influence of male genotype on life span of 
mated age-1 hermaphrodites is real.  We also are mating age-1 
hermaphrodites with BA713 which contains fer-15(b26ts), a gene closely 
linked to age-1 and present in TJ412, to see if this sperm defect 
interacts with life span.  Correlations between life span and total 
progeny production in T1412 hermaphrodites mated to N2 or TJ412 males 
tended to be negative, and repeats will firm up this observation.