Embryos that lack maternal cos function (derived from females carrying homozygous germ line clones) have a weak abdominal segmentation defect (fused segments). Embryos that lack both maternal and zygotic cos function (derived from females carrying homozygous germ line clones mated to mutant males) have a strong segment polarity phenotype. Few embryos hatch. Homozygotes do not survive to adulthood.
Embryos derived from females carrying homozygous germline clones have a segment polarity phenotype.