Isolation and characterization of Df(2L)BSC100 Jennifer Deal and Kevin Cook Bloomington Stock Center Indiana University Df(2L)BSC100 was isolated as a FLP recombinase-induced recombination event involving PBac{WH}f00023 and P{XP}d04701. The deletion was isolated as a chromosome lacking miniwhite markers in progeny of P{hsFLP}1, y1 w1118; PBac{WH}f00023/ P{XP}d04701 males crossed to w1118; P{w+mC=hs-hid}2, wgSp-1/CyO 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}BSC100 from the segment of PBac{WH}f00023 to the left of its FRT site and the segment of P{XP}d04701 to the right of its FRT site. Its presence was verified using the PCR methods and primers described in Parks et al. Exelixis, Inc. determined the insertion site of PBac{WH}f00023 to be at Release 3 genomic coordinate 21697703 on chromosome arm 2L and the insertion site of P{XP}d04701 to be at Release 3 genomic coordinate 21732645 on arm 2L. The Gene Disruption project determined the insertion site of PBac{WH}f00023 to be at Release 3 genomic coordinate 21697945 on arm 2L. The cytological breakpoints of Df(2L)BSC100 predicted from these coordinates are 40B1;40B3. Df(2L)BSC100 failed to complement Df(2L)Exel6049.