SCALLOPED WINGS IS THE LUCILIA-CUPRINA NOTCH HOMOLOG AND A CANDIDATE FOR THE MODIFIER OF FITNESS AND ASYMMETRY OF DIAZINON RESISTANCE

The Scalloped wings (Scl) gene of the Australian sheep blowfly, Lucili a cuprina, is shown to be the homologue of the Drosophila melanogaster Notch gene by comparison at the DNA sequence and genetic levels. A L. cuprina genomic fragment, which shows strong identity with the Notch (N) gene at the molecular level, hybridizes to the location of the Scl gene on polytene chromosomes. The two genes are functionally homologo us; the dominant and recessive Notch-like phenotypes produced by mutat ions in the Scl gene allow these alleles to be classed as N-like or Ab ruptex-like. The Scl gene is under investigation as a candidate for th e fitness and asymmetry Modifier (M) of diazinon resistance. We show t hat M affects the penetrance of wing and bristle phenotypes associated with two Scl alleles in a manner consistent with the M being an allel e of Scl. In addition, we report a phenotypic interaction between the diazinon-resistance mutation, Rop-1, and the same alleles of Scl. We p ropose that the product of Rop-1, an esterase, may be involved in cell adhesion in developmental processes involving the Scl gene product.