Deletion removing all Yp2 coding region and 5' flanking region, leaving Yp1 coding region and 5' sequences to position -321 with respect to start of Yp1 transcription. A fragment of bacteriophage M13 DNA has been inserted into the transcription unit to allow the transcript produced by this construct to be distinguished from endogenous Yp1 transcripts.
Yp1 5' sequence to -321 with respect to start of transcription is sufficient for directing female-specific expression.