Transgenic construct used to study the Mcp boundary element from the regulatory region of the Abd-B gene. Consists of the y body and wing enhancers, a FRT cassette containing the 1.5kb UbxPRE, a loxP cassette containing a 340bp insulator from the Mcp boundary element of Abd-B, the y gene (including the bristle enhancer), two tandem copies of the w eye enhancer and a mini-w gene.