Isolation and characterization of Df(2R)BSC659 Stacey Christensen, Kim Cook and Kevin Cook Bloomington Stock Center Indiana University Df(2R)BSC659 was isolated as a FLP recombinase-induced recombination event involving P{XP}aptd01747 and PBac{WH}Nxt1f04855. The deletion was isolated as a chromosome lacking miniwhite markers in progeny of P{hsFLP}1, y1 w1118; P{XP}aptd01747/PBac{WH}Nxt1f04855 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}BSC659 from the segment of P{XP}aptd01747 to the left of its FRT site and the segment of PBac{WH}Nxt1f04855 to the right of its FRT site. Its presence was verified using the PCR methods and primers described in Parks et al. The cytological breakpoints of Df(2R)BSC659 predicted from the Release 5 genomic coordinates of the transposable element insertions sites are 59F1;60A2. Df(2R)BSC659 failed to complement Df(2R)BSC136 and retn02535.