Genomic sequence has been inserted into the attP site in TI{TI}witattP, reconstituting a wit locus in which 21bp of the witZ enhancer at the 5' end of the locus (this 21bp fragment contains a brk/P-Mad/Med site in D. melanogaster) has been replaced with the corresponding sequence from D. virilis. Sequence encoding a loxP site, a wGMR.PHb marker, a loxP site, the Disc\RFPDsRed.3xP3.cUa marker and a loxP site is present downstream of the reconstituted locus.