Drosdel Deficiencies Deficiencies listed below were donated by the DrosDel Project. They have molecularly defined breakpoints and are in an isogenic background. DrosDel starter stocks are also available. Primary reference for these deficiencies: Ryder et al. 2004 See also Cook et al. 2012 and Roote & Russell 2012 DrosDel Project maps of deletion coverage may be viewed here.