Practice question

Aardvark locus encodes beta-catenin homologue interacting with alpha-catenin to link cadherin-like adhesion protein DdCAD-1 to actin cytoskeleton. During culmination, coordination of prestalk cell movement down stalk requires intact adherens junctions and single organizer tip. Aar null mutants fail to maintain tip integrity; tip fragments generating multiple ectopic stalk tubes rising from basal mass, phenotype termed multiple tipped mounds or multiple stalk formation. SmlA controls aggregate size, aca controls early aggregation, ACG controls germination, therefore none produce multiple stalks. Aar function illustrates conservation of beta-catenin role in maintaining organizing centers and suppressing secondary axis formation parallels vertebrate embryo development.