Knockdown of genes required for cell fate specification and/or positioning leads to diverse, distinct phenotypes in the Germ Layer and Morphogenesis strains. Genes scored as having a defect in cell fate and/or positioning were partitioned into three classes based on analysis of nuclear counts: (1) genes whose inhibition leads to incomplete cell fate specification due to arrest prior to the completion of cell division, (2) genes whose inhibition leads to an abnormal nuclear pattern despite normal numbers of each type of nuclei and (3) bona fide genes cell fate specification genes. This movie shows side-by-side views of the phenotypes in the first two classes in the Germ Layer (top) and Morphogenesis (bottom) strains. See text for description of the plrg-1, arx-1, arx-3, gex-2 and die-1 knockdown phenotypes. APS-1, is an adaptin complex subunit involved in the formation of intracellular transport vesicles (Boehm and Bonifacino, 2001); aps-1(RNAi) embryos typically arrested without rupture, but with severe defects in epidermal and nervous system morphology. LET-19 is a component of the mediator complex previously shown to modulate the transcription of several genes involved in development (Wang et al., 2004; Yoda et al., 2005); let-19 knockdown led to defects in epidermal morphology that were frequently accompanied by rupture of the epidermis at the embryo anterior. Playback is 7200X real time.