Isolation and characterization of Df(2L)BSC810 Stacey Christensen, Kim Cook and Kevin Cook Bloomington Stock Center Indiana University Df(2L)BSC810 was isolated as a FLP recombinase-induced recombination event involving PBac{WH}nompCf00642 and P{XP}d04336. The deletion was isolated as a chromosome lacking miniwhite markers in progeny of P{hsFLP}1, y1 w1118; PBac{WH}nompCf00642/P{XP}d04336 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.WH5}BSC810 from the segment of PBac{WH}nompCf00642 to the left of its FRT site and the segment of P{XP}d04336 to the right of its FRT site. Its presence was verified using the PCR methods and primers described in Parks et al. The breakpoints of Df(2L)BSC810 predicted from the Release 5 genomic coordinates of the transposable element insertion sites are 2L:5352777 ;5547113 and the cytological breakpoints predicted from these coordinates are 25D6;25E6. Df(2L)BSC810 failed to complement CG7277KG03584 and Hel25Ek11511.