Timelapse of dorsal yolk syncytial layer (YSL) nuclear movements during zebrafish gastrulation. A marginal band of YSL nuclei undergo epiboly toward the vegetal pole while internal-YSL (I-YSL) nuclei move away from the margin and toward the animal pole. Starting about mid-gastrulation (70% epiboly), YSL nuclei begin converging toward the dorsal midline and extending along the anteior/posterior axis. Note CIL 11801 and CIL 11802 are the same video. CIL 11802 is a 3D video that can be viewed with red blue colored glasses. Video made available by Mark Cooper through Zebrafish - The Living Laboratory.