Movie 1.

(related to Fig. 1). SCP migration on the primordial vein and caudal venous plexus formation Maximum projection and orthogonal transverse section reconstituted by Imaris software from the confocal time-lapse imaging of a Tg(Pax3a:GFP; kdrl:ras-mCherry) embryo from 26 to 35 hpf. Horizontal lines at the beginning of the movie indicate the correspondence between the lateral and orthogonal view. Endothelial cells are mCherry+; the caudal artery is overlaid by the somites, while the forming venous plexus lies ventral to the somites. Migrating SCPs ar GFP+; GFP++ cells migrating from the top (dorsal side) into the future CHT (ventral side) after the SCPs are neural crest cells that will differentiate in pigment cells.