GENETIC CHARACTERIZATION OF THE 87C REGION OF THE THIRD CHROMOSOME OF <i>DROSOPHILA MELANOGASTER</i>

Abstract

Ethyl methanesulphonate (EMS) was used to induce 39 lethal and 13 karmoisin mutations within Df(3R)kar(3J), a nine-band deficiency extending from 87C1 to 87C9 (inclusive). Five complementation groups (four lethal and one visible) were identified and cytologically mapped between 87C4-5 and 87C9, one complementation group per band, with the exception of complementation group A, which is localized to 87C4-5. These positions were determined using a set of overlapping deficiencies, each having at least one breakpoint in the 87C1-9 region. Mutations within a single complementation group have similar lethal phases or subvital phenotypes, consistent with the notion that each complementation group represents a single functional locus. No mutations localized to 87C1-C3. The inability to induce mutations in the 87C1 heat-shock puff locus is consistent with the current interpretation of a duplication of coding sequences at the 87A7 and 87C1 heat-shock puffs.