Part of the wg first exon has been deleted and replaced with the following reintegrated sequence: 1. a recombined attP/B site, 2. a single FRT site, 3: sequence encoding a QF driver (which is expressed under the control of the endogenous wg regulatory sequences) and 4: a loxP cassette containing a Disc\RFPmCherry.3xP3 marker. This allele is generated by excision of an FRT cassette from either of two progenitor alleles - wgKO.FRT.wg.FRT.QF or wgKO.FRT.NRT-wg.FRT.QF. Excision of the FRT cassette from either of these progenitor alleles results in an allele with an identical structure.