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.
btlunspecified is an enhancer of larval intersegmental nerve phenotype of gcmunspecified
The addition of btlunspecified enhances the ISNb bypass phenotype seen in gcmunspecified animals. ISNb still defasciculate properly in a large fraction of hemisegments.