Isolation and characterization of Df(3R)BSC141 Rachel Andrade, Jill Gresens, and Kevin Cook Bloomington Stock Center Indiana University Df(3R)BSC141 was isolated as a FLP recombinase-induced recombination event involving P{XP}d05753 and PBac{RB}e02721. The deletion was isolated as a chromosome lacking miniwhite markers in progeny of w1118; P{hs-hid}3, Dr1/TM6B females crossed to P{hsFLP}1, y1 w1118; P{XP}d05753/PBac{RB}e02721 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}BSC141 from the segment of P{XP}d05753 to the left of its FRT site and the segment of PBac{RB}e02721 to the right of its FRT site. The cytological breakpoints of Df(3R)BSC141 predicted from the transposable element insertions sites using release 4 coordinates are 92F2;93A1. Df(3R)BSC141 failed to complement cdc2c3 and CG1783803806.