STAT3 and scoliosis: Moreover, Alizarin Red staining at 15 dpf failed to reveal any structural abnormalities in stat3 mutants in the notochord or differentiating vertebrae (between the swim bladder and the cloaca) (Fig 2D), indicating that the scoliosis phenotype in stat3 mutant fish is likely not of congenital but of idiopathic type.