Homozygous somatic clones in the wing lead to a number of defects, including notched wing margins and ectopic vein material. Clones of mutant cells in the intervein regions also alter the hair polarity of the surrounding wild-type cells. In the notum, mutant clones cause notal clefts. In the eye, mutant clones cause small and rough eye. Incorrect rotational direction is seen in wild-type ommatidia adjacent to the clone. Furthermore, both ommatidia rotation and organisation within the mutant eye clone becomes disorganised, with some ommatidia missing outer photoreceptor cells, while others contain extra cells or abnormally shaped rhabdomeres. In embryos lacking maternal Gug, about half fail to develop, all those that do develop have missing and misshaped ventral denticle belts, about 2/3 have holes and patches of naked cuticle. Amongst the embryos with at least one complete ventral denticle belt (just over half) a quarter have obviously widened belts. Hyperplasia of neuronal tissue is also seen in these embryos.