Isolation and characterization of Df(3L)BSC576 Stacey Christensen, Kim Cook and Kevin Cook Bloomington Stock Center Indiana University Df(3L)BSC576 was isolated as a FLP recombinase-induced recombination event involving PBac{RB}CG32048e04063 and P{XP}CG8177d00052. The deletion was isolated as a chromosome lacking miniwhite markers in progeny of w1118; P{hs-hid}3, Dr1/TM6C,Sb1 females crossed to P{hsFLP}1, y1 w1118; PBac{RB}CG32048e04063/P{XP}CG8177d00052 males. The 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}BSC576 from the segment of PBac{RB}CG32048e04063 to the left of its FRT site and the segment of P{XP}CG8177d00052 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'-CCAATGCGTTTATTTCAGGTCACG-3' for the RB3' plus or RB3' minus primer in the Hybrid PCR protocol in the Supplementary Methods. The cytological breakpoints of Df(3L)BSC576 predicted from the Release 5 genomic coordinates of the transposable element insertions sites are 67C1;67C7. Df(3L)BSC576 failed to complement alphaTub67C1.