Worm Breeder's Gazette 9(2): 99
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.
Last year we reported our early analyses of the long-lived mutant strains isolated in the DH26 background (fer-15(b26)) by Mike Klass. One of the longest-lived mutants, MK546 (age-1(hx546)), is also unc-31( z1) IV, male sterile and exhibits a decreased brood size (Brd). MK546 was backcrossed to N2 males and the F2 were subcloned to the F5 in the first experiment and to the F15 in a repeat experiment to establish homozygous age-1 reisolate stocks. age and unc do not cosegregate in the reisolates, nor is there a correlation between age and a decreased development rate (determined by measuring worm length) nor between age and the time at which 50% of the population is fecund. However, further tests have shown that both fer-15 and brd cosegregate with age. This is contrary to our initial report which we now believe to be incorrect based on the more complete repeat of the original experiment. The segregation of age and brd is consistent with a single nuclear gene. We have not, as yet, been able to separate the age or brd phenotypes conferred by the age-1 locus from fer-15. We are now using both brd and fer as predictors of age in homozygous reisolate stocks due to the relative ease of assay. Several complementation tests for life-span between the age (long- life) locus of MK546 and the age loci of MK31 and MK542 (also isolated by Klass) suggest that age-1(hx546) fails to complement age(hx542), but does complement age(hx31) to yield F1 which display non-age ( normal) life-span, although we are still confirming this last result. Two complementation tests for brd suggest that MK546, MK542 and MK31 are allelic for the locus. Both the age and brd complementation data are consistent with observations by Paul Fitzpatrick showing that age in MK31 does not cosegregate with the brd and fer phenotypes also found in that strain. The isolation of two new phenotypes (age and brd) tightly linked to fer-15 is unusual. Several events could explain this linkage. Models include mutations conferring a pleiotropic effect of the fer-15 locus, a polar Tc1 insertion and multiple tightly-linked mutational events or a chromosomal inversion. We have excluded Tc1 as a causative agent because we observe no new band(s) after probing genomic DNA from both age and non-age stocks with pCe2002(Tc1).