Worm Breeder's Gazette 11(4): 82
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.
In the course of making N2/B0 recombinants for another reason, two spontaneous mutations popped up on successive days from a N2/RW7000 background. One was a new dpy-20 allele (e2480), the other a strong Unc(e2498). After 10 backcrosses to N2, the phenotype of the Unc remained strong (there is no new Tc1 band on a Southern blot of e2498). It mapped to LGIII, left of dpy-18, right of sma-2, inseparable from vab-7, was uncovered by eDf2, and complemented unc-25, -47, -49, -71 and -81. The phenotype did not change over eDf2. Since this data did not correspond to the position of any known Unc gene, I assigned e2498 to a new gene, unc-119. Since then, I have shown that e2498 is not complemented by eDp6.e2498 is a severe Unc, capable of very little body movement. It is slightly dumpier than wild-type, a coiler, assuming a 'J' shape on the plate. Pharyngeal pumping is normal, and the head seems to be capable of more movement than the rest of the body. e2498 is neither ts nor cs, not Egl, and the phenotype seems equally severe throughout development. e2498 maps very close to the breakpoint of both eDf6 and eDp2. Jonathan Hodgkin reminded me that the original strain carrying eDf2 and eDp6, both of which presumably resulted from the same acetaldehyde mutagenesis event, was isolated as a strong Unc with aberrant segregation (Hodgkin, Genetics 96:649, 1980). Possibly, the chromosomal breakpoint was in or near an Unc gene (generating a ring chromosome [Hunter and Wood WBG 10#2 p150]?). I found that the phenotypes of the two strains (e2498 and eDf2/eDf2;eDp6), were very similar, although eDf2/eDp6 may be slightly dumpier. There is no reason to think that e2498 is a large chromosomal lesion, but it seems surprising that a 'simple' allele of it has not been isolated before. Obviously if this is the lost eDf2/eDp6 Unc, it should be relatively easy to isolate by looking in the region for the chromosomal breakpoints.