Homozygous embryos become abnormal during gastrulation; the germband twists and extends laterally rather than extending dorsally as in wild-type embryos. Near the completion of germband extension, the embryos show a distinct separation between the mesodermal and ectodermal tissue layers. The cuticle often has a dorsal hole. There are often fewer pericardial cells than in wild-type embryos, resulting in distinct gaps in the heart tube. The pericardial cells appear to dissociate randomly and the heart tube often appears to curve off towards the lateral side of the embryo. Significant gaps are seen in the dorsal trunk of the trachea. Somatic myotubes are often not attached to target epidermal attachment sites. This defect is most commonly seen in the ventral oblique muscles located in the anterior most segments of the embryo. Random disorganisation of myotubes and areas without myotubes are also occasionally seen. The number of photoreceptor cells is not altered in homozygous clones in the eye, but they appear disorganised.