Early 1997 International Worm Meeting abstract 20 The daf-12 nuclear receptor advances life stages and specifies the dauer diapause. C. elegans has six recognized stages, embryo, larval stages L1-L4, and adult, with options for the dauer diapause at the L3 stage. A handful of heterochronic loci specify developmental age in the various tissues. Mutants generally fail to express programs of L3 and later larval stages on schedule, often repeating cell lineage, pathfinding, and molting programs of the previous stage. Mutants also inappropriately choose between continuous and dauer development, as revealed by dauer defective and dauer constitutive alleles.
Alleles fall into six classes based on somatic, gonadal and dauer phenotypes.
Correlatively, alleles within a class molecularly cluster within DNA or ligand binding domains of the predicted protein. Interestingly, this gene belongs to an ancient branch of the nuclear receptor family, suggesting a conserved role in insects and perhaps other phyla.