Southpaw (Spaw) regulates the direction of epithalamic asymmetry. Spaw MO-depleted larvae show either a WT (sinistral; A,C,E,G,H) or reversed (dextral; B,D,F,I,J) pattern of epithalamic laterality. (A,B) Dorsal view of fluorescently labeled pineal complex in foxD3:GFP transgenic larvae at 2 days. Position of the parapineal is indicated (white arrowhead). (C,D) Dense neuropil in the habenular nuclei is revealed by confocal imaging of anti-acetylated tubulin immunofluorescence in a 4-day larva. (E,F) Asymmetric expression pattern of the lov gene at 4 days. (G-J) Whole-mount in situ hybridization to detect lov habenular expression (open arrowhead) and insulin transcripts in the pancreas (black arrowhead) reveals the four major classes of larvae obtained following spaw MO injection. The direction of habenular asymmetry and L-R positioning of the pancreas are randomized, but in an independent manner. All images are dorsal views, anterior to the top. Scale bar: 8 mm (A,B); 20 mm (C,D).