Movie 4.

Perfusion of the primitive pectoral artery. Time-lapse confocal imaging of a Tg(kdrl:egfp)^s843, Tg(gata1:dsred)^sd2Tg double transgenic zebrafish from 44–50 hpf, showing gata1:dsred marking active blood flow (left panel; pec fin flow colored red), Tg(kdrl:egfp)^s843 showing both lumenized and unlumenized vessels (center panel; ventral connection to the DA colored green), and a merged Tg(gata1:dsred)^sd2Tg (red)/ Tg(kdrl:egfp)^s843 (green) image (right panel). Flow initially shunts from the DA directly to the CCV, but then becomes re-routed through the full arc of the primitive pectoral artery. Each frame of the movie represents 20 minutes elapsed time. The movie shows the complete sequence for the images shown in Fig. 4J–U.