Fig. 4. Correspondence between parapineal and habenular laterality. (A) In the majority of wild-type 4 d larvae, the parapineal (black arrowhead, otx5 expression) is on the left, beside the habenula with high lov expression (red). (B) LR reversal of parapineal and habenular laterality is sometimes observed in wild type (n=20/395). (C) Paired parapineal organs and bilateral lov expression in the habenulae is found infrequently (n=1/395). (D) Almost half of rescued MZoep larvae show the wild-type pattern, while the other half (E) show a LR reversal in laterality. (F) Bilateral expression of lov in rescued MZoep mutants also occurs when two parapineals form (partially obscured by intense otx5-expressing pineal). (G) flh mutants have a greatly reduced pineal anlage (Masai et al., 1997). The majority of otx5-expressing cells in flh mutants are presumed to be parapineal because of their lack of flh expression (Gamse et al., 2002). In half of flh mutants, the parapineal and stronger lov expression are found on the left side, and (H) in the other half, laterality is reversed. (I) The parapineal is sometimes found medially, adjacent to both habenulae (5/84). In these flh mutants, lov is expressed strongly in both habenulae. Scale bar: 50 µm. See also Table 2.