N sequence in which the opa nucleotide repeats of the eighth exon encode a shorter than normal polyQ tract of 23 amino acid residues (Q13-Q10) in which the histidine that normally interrupts the polyQ tract is not present.
The Nopa23 allele is likely deleterious, resulting in increased embryonic failure (failure to hatch) in many genomic backgrounds. The Nopa23 allele is associated with classic N mutant phenotypes including defects in patterning of the macrochaetae and wing notching.
