Polytene chromosomes normal.
Point mutation.
Strong phenotype. Embryos almost completely lack cuticle: due to cell death in epidermal primordium. Morphogenetic abnormalities in the developing tracheal system result in few remaining aggregates of tracheal cells. Morphogenetic abnormalities and cell death were detected in the presumptive foregut and hindgut. Salivary glands also undergo cell death.
Strong crb allele.