Using ethylmethane sulfonate (.05M) several lethals linked to the
unc-22 mutant have been isolated (14 lethals in 320 tested fourth chromosomes within 5 map units i.e. 4.4%). Worms heterozygous for the mutant
unc-22 show a different behavior in a solution of 1% nicotine than do wild-type worms. This observation has allowed us to keep lethals linked to the
unc-22 mutant for further study. Ten of the lethals have been found to map within two map units either side of the twitcher gene. Several of these have now been given left/right positions. As well, the time of lethality for eight of these mutants has now been determined. All eight are post-embryonic lethals. One dies in the egg just prior to hatching. Six die during various larval stages. One grows to the adult size but it is sterile. The evidence of linkage data, complementation analysis, left/right positioning and time of lethality lead us to the conclusion that we have identified ten separate lethal genes around the
unc-22 gene. This work is supported by a grant from the National Research Council of Canada.