Df(2R)BSC879 was isolated as a FLP recombinase-induced recombination event involving P{XP}Ef1alpha48Dd10427 and PBac{RB}CG8378e02998. The deletion was isolated as a chromosome lacking miniwhite markers in progeny of P{hsFLP}1, y1 w1118; P{XP}Ef1alpha48Dd10427/PBac{RB}CG8378e02998 males crossed to w1118; P{hs-hid}2, wgSp-1/SM6a females. These males were heat shocked as larvae as described in Parks et al., Nature Genetics 36: 288-292, 2004 (FBrf0175003). This cross and crosses in preceding and succeeding generations maintained the original genetic background of the Exelixis insertion stocks (Thibault et al., Nature Genetics 36: 283-287, 2004; FBrf0175002). The recombination event generated the genetic element P+PBac{XP5.RB3}BSC879 from the segment of P{XP}Ef1alpha48Dd10427 to the left of its FRT site and the segment of PBac{RB}CG8378e02998 to the right of its FRT site. Its presence was verified using the PCR methods and primers described in Parks et al. with the substitution of the primer 5’-GCTTCTAAACGCTTACGCATAAACGATG-3’ for the RB3’ plus or RB3’ minus primer in the Hybrid PCR protocol in the Supplementary Methods. The breakpoints of Df(2R)BSC879 predicted from the Release 5 genomic coordinates of the transposable element insertion sites are  2R:7779605 ;8029867 and the cytological breakpoints predicted from these coordinates are 48C5;48E2. Df(2R)BSC879 failed to complement jebk05644.