Single nucleotide substitution disrupting the splice acceptor site in the first intron.
An unspecified mutation in the splice acceptor site in the first intron. The splice site mutation has been arbitrarily mapped by a FlyBase curator to the first base of the splice acceptor site.
Mutants show premature loss of the optic lobe, with a swath of neuroblasts in the place of neuroepithelia and a fragmented neuropil in the third instar larval optic lobe.