PRODUCTION OF DOMINANT FEMALE STERILITY IN DROSOPHILA-MELANOGASTER BYINSERTION OF THE OVO(D1) ALLELE ON AUTOSOMES - USE OF TRANSFORMED STRAINS TO GENERATE GERMLINE MOSAICS

We have cloned a 7 kb genomic fragment containing the dominant female- sterile mutation ovo(D1). This fragment confers to transgenic females a sterility phenotype, the severity of which depends both on the genet ic background and the ratio of ovo(D1) product to ovo(+) product. Fema les containing two copies of the ovo(D1) transgene, or those containin g one recessive null allele at the ovo locus, are about as sterile as ovo(D1) females. Twenty transformed strains were obtained and five of them were tested and shown to be excellent tools for identifying a ger mline clone of cells sustaining mitotic recombination on the autosomes . One of the tested strains carries an insert on chromosome 4, which e nabled us to show that mitotic recombination on that chromosome is not a rare event: it is in fact frequent enough for the maternal effects of the zygotic lethal mutations cubitus interruptus Dominant (ci(D)) a nd l(4)29 to be studied.