Transgenic construct used in a study to characterize a pairing-sensitive element in the eve 3' boundary region. A 300bp fragment ('PRE300') containing an active portion of a pairing-sensitive element near eve (fragment extends from +8.9kb to +9.2kb relative to the eve transcription start site), with a of the pho protein-binding site (GCCATCTT to ACAGGCGA), has been inserted upstream of the gl binding sites present in w+mCG.