FlyBase curator comment: this entry is used to capture phenotypic information when the particular allele (or allele combination) used by the author could not be determined but the context of the experiment suggests that the phenotype being described is some kind of loss of function.
Homozygous embryos do not show muscles crossing the ventral midline at stages 13-15 or inner Fas2-positive axons crossing the midline at stages 16 and 17.