Transgenic construct that contains a Ecol\lacZarm.PV reporter flanked on each side by an insulator (scs' and scs respectively) to mitigate any chromosome position effects. A 6.2kb EcoRI fragment from cosmid p11E3 (chromosomal location 1B) has been inserted (upstream of the arm promoter of the lacZ reporter) to test whether the fragment has a role in dosage compensation.