Fig. 5. Distribution of different cell types in the dorsal aorta in different categories of clone. (A) The numbers of labelled endothelial (E), periendothelial (P) and vascular smooth muscle (vSM) cells in different categories of clones, at E10.5. (B) Schematic diagram showing progenitors for the myotome (My) and dorsal aorta (summarizing all cell types observed) for each category of clone. The progenitors of long clones and short clones give rise to endothelial cells (E), as well as mural smooth muscle cells. The predominant cell type - periendothelial (P) or vascular smooth muscle (vSM) - in the dorsal aorta is indicated in heavy type. (C) The same as A, at E9.5. DA, dorsal aorta only. (D) At E9.5, a similar lineage tree to those in B, is shown for the category of single somite clones.