Patterned nuclei movements in the dorsal yolk syncytial layer( YSL) after mid-gastrulation. Anterior is up. Timelapse includes Nomarski images (left panel), fluorescence (right panel) and overlay (middle panel). The timelapse begins at shield stage and ends at bud stage, 4.7 hours later. Nuclei initially located under the shield extend along the dorsal side by the end of gastrulation. Nuclei initially located at the animal pole are displaced towards the ventral and lateral domains by dorsal nuclei flowing up through the animal pole region. Concurrently, lateral nuclei converge toward the dorsal midline and intercalate between dorsal midline nuclei. Sphere is approximately 700 microns in diameter. Video made available through Mark Cooper and Zebrafish The Living Laboratory.