Imprecise excision of the P{EPgy2}TrehEY06982 progenitor insertion. There is no deletion of genomic Treh sequence and at least 38bp of the original element remains at the insertion site.
Homozygotes die at the late third larval instar or pupal stages, with 6% escaping to adulthood.
The outer proliferation center neuroepithelium is largely disintegrated in the brains of late third instar homozygous larvae.