Lethal phase is during embryogenesis/larval stages. 40% of geminink14019/Df(2R)ST1 animals die before hatching and the rest die during larval development (third instar larvae are occasionally seen). 100% of stage 12 geminink14019/geminink09107 ovaries show strong BrdU labeling in 4 amplification foci in all follicle cells (wild-type ovaries at this stage mostly have only one focus of DNA amplification per cell). By stage 14, all follicle cells of wild-type ovaries have ceased DNA amplification, but many follicle cells from 50% of mutant ovaries still continue DNA amplification.
Lethality occurs during third instar larval or pupal stages. Mutants exhibit visible disc abnormalities: very small or no discs. Clones cannot be induced in wild type discs. In tergites, clones with normal size and but lower than expected frequency are recovered. Clones cannot be recovered in the wing disc.