The PBac{RB5.WH5} transgene represents a hybrid element produced by FLP-mediated recombination between an insertion of a PBac{RB} element and an insertion of a PBac{WH} element. PBac{RB5.WH5} consists of: terminus derived from the Tni\piggyBac 5' end - w^+mC marker - single FRT site - 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) - terminus derived from the Tni\piggyBac 5' end. PBac{RB5.WH5} 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 PBac{RB} and a PBac{WH} insertion can result in either a PBac{RB5.WH5} or a PBac{RB3.WH3} hybrid element, depending on the relative genomic locations and orientations of the original insertions.