Mosaic animals in which the retina is homozygous for sd-323 (generated using the "EGUF/hid" system) have normal external eye morphology but show defects in a phototaxis assay. The electroretinogram of mosaic animals in which the retina is homozygous for sd-323 shows activity-dependent loss of the off transient only. Hemizygotes die as pupae.
Separable from: separable lethal mutation. The sd-323 chromosome probably carries a second site lethal mutation, since hemizygotes die as pupae, while homozygotes die as first instar larvae.