Fig. 2. Examples of -cardiac actin^nlaacZ1.1/+ embryos with ß-gal⁺ cells in the dorsal aorta. (A) The different categories of clones at E10.5 are shown, with right and left lateral views to reveal cells in the myotomes (^*) of the somites on either side of the neural tube and a ventral view (centre) to reveal cells (delimited by arrowheads) in the dorsal aorta. An enlargement of this region is shown as an inset (indicated by arrow). The position (not precise number) of labelled cells (black dots) in each clone is shown schematically on the right of the figure. Right (R) and left (L) somites (1-34) are presented on either side of the dorsal aorta. The hypaxial (H) and epaxial (E) extremities of the somites are indicated. (B) The different categories of clones at E9.5 are shown, with ß-gal⁺ cells in the dorsal aorta. Right and left lateral views reveal cells in the myotome (^*) of somites on either side of the neural tube. A ventral view (centre) shows the dorsal aorta where ß-gal⁺ cells are delimited by black arrowheads. An enlargement of this region is shown as an inset (indicated by arrow). The position (not precise number) of labelled cells is shown schematically on the right of the figure. Right (R) and left (L) somites (1-25) are presented on either side of the dorsal aorta, which has not yet fused anteriorly.