The P+PBac{XP3.WH3} transgene represents a hybrid element produced by FLP-mediated recombination between an insertion of a P{XP} element and an insertion of a PBac{WH} element. P+PBac{XP3.WH3} consists of terminus derived from the P-element 3' end - UAS regulatory sequences (oriented so that in the presence of a GAL4 driver, transcription from UAS is directed outwards from the end of the element) - gypsy insulator sequence - w^+mC marker - single FRT site - w^+mC marker - gypsy insulator sequence - terminus derived from the Tni\piggyBac 3' end. P+PBac{XP3.WH3} is typically generated as part of a deletion-generation strategy; when the two insertions are in trans and are in the appropriate relative orientation, FLP-mediated recombination can result in deletion of the genomic region between the two original insertions along with production of the hybrid element at the recombination point. FLP-mediated recombination between a P{XP} and a PBac{WH} insertion can result in either a P+PBac{XP5.WH5} or a P+PBac{XP3.WH3} hybrid element, depending on the relative genomic locations and orientations of the original insertions.