(F-G') Lateral images of the cranial vessels in etv2:Kaede embryos, with unconverted tissue shown in green (F-G) while photoconverted tissue is shown in red (G'). The earliest visible form of the VA-L was photoconverted at 29 hpf (F), then followed through to 54 (G). G' is a higher magnification image of the box in G and is accompanied by a red channel only (traced photoconverted cells) image with the VA-L (dotted line) demarcated from the adjacent VA, and VA-L photoconverted cells indicated (arrowheads). 