Retains seven IGS repeats.
Deletion derivative that retains a segment of the 5' and 3' intergenic spacer (IGS) but deletes the bb transcription unit.
Improves neither recovery of reciprocal products from Df(1)X-1/Dp(1;Y)BSYy+ males nor male fertility. Increases fertility of Df(1)X-1; T(Y;2)B80 from 0 to 22.6%.