Fig. 3. Whole mount in situ hybridization of pigment cell specific genes. In situ hybridization with antisense RNA DIG-labeled probe for the SpPks gene (A-D), SpFmo1 gene (E-H) and SpSult gene (I-L) on embryos at different developmental stages: hatched blastula side view (A,E,I) and vegetal view (B,F,J); gastrula side view (C,G) and apical view (K); pluteus oral view (D,H,L). In situ hybridization for SpFmo2 and SpFmo3 were also carried out (data not shown). All the genes examined are expressed in pigment cell precursors at the blastula stage and their expression is maintained in pigment cells throughout the gastrula and pluteus stages.