Worm Breeder's Gazette 2(2): 10a
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.
A series of mutants affected in dauer larva formation is being used to determine the nature of the genetic program for this aspect of development. Mutant genes have been ordered with respect to one another in a genetic pathway based on analysis of epistatic relationships. The genes already characterized apparently specify a signal pathway (or pathways) for dauer formation. One class of mutant is non-chemotactic and exhibits abnormal sensory ultrastructure. A search for mutants which are temperature-sensitive in their ability to recover from the dauer state was based on selection of SDS- resistant larvae in populations recovering from starvation. As expected, this selection turned out to be a good method for obtaining dauer-constitutive mutants, since slow recovery is often associated with constitutive entry into the dauer state. Furthermore, starved plates usually contain F3 dauers, so that constitutive mutants with maternal effects are readily detected. Four new alleles of a previously characterized dauer-constitutive gene, daf 1, have been obtained. All mutant alleles of this gene exhibit a maternal effect except for one allele which is lethal. The only recovery-defective mutants isolated were non-ts, but extremely leaky. This result is consistent with other genetic evidence suggesting that the process of recovery shares common steps with the entry process. Good recovery mutants probably cannot be found by direct selection because many of these mutants are, in fact, dauer-defectives. When dauer-defective mutants are forced to enter the dauer state by the introduction of an epistatic ts dauer- constitutive mutation the dauers formed are unable to recover even at the permissive temperature. This strongly suggests that the genes normally required for entry are required for recovery as well.