For the nvyΔ mutation, the deletion extends from -132bp to +381bp relative to the first nucleotide of the nvy coding sequence (the 'A' of the ATG start codon of nvy-RB and nvy-RC). The 20bp of sequence flanking the nvyΔ deletion are - 5': acttgatgttttcgtctatc-(beginning of deletion) - 3': (end of deletion)-aataggcattgttaggatta