AN EMBRYOLOGICAL STUDY OF VENTRALIZATION OF DORSAL STRUCTURES IN THE TAIL OF MEDAKA (ORYZIAS-LATIPES) DA MUTANTS

In adult Da (double anal fin) mutants of medaka (Oryzias latipes), str uctures such as the dorsal fin and the dorsal half of the caudal fin a re ventralized in adult fish. However, there have been few embryologic al studies of the development of mutant phenotypes except those of the caudal fin. in this study, development of mutant phenotypes of the ta il where they typically develop was examined morphologically at variou s stages of embryogenesis. The arrangement of melanocytes along the do rsal midline, the shape of the dorsal fin fold, and the shape of the d orsal myotome exhibited a ventral pattern in the tail al various embry onic stages in Da mutants.