FlyBase curator comment: this entry is used to capture phenotypic information when the particular allele (or allele combination) used by the author could not be determined but the context of the experiment suggests that the phenotype being described is some kind of loss of function.
The brain lobes remain exposed in mutant embryos instead of being internalised, indicating a failure of the dorsal ridge to migrate and enclose the brain in epidermis.
yrtunspecified mutant embryos have a dorsal posterior hole.