title: The zeste-white interaction: induction and genetic analysis of a novel class of zeste alleles.
abstract: The recovery and analysis of a novel class of zeste mutations is described. z and z do not require two w genes for their expression unless the z gene is present. Analysis of genetic interactions among zeste alleles proved that z mutations are strong antagonists of the z gene product. z is readily reverted by X-rays or by ethylmethane sulphonate to a range of intermediate zeste alleles and thus it is considered to be an insertional mutation. We suggest that z and op mutations arose as a result of insertions in a presumptive control region, and two alternative models for the structure of the zeste locus are evaluated.
authors.affiliation: Department of Biology, TECHNION-Israel Institute of Technology, Haifa, Israel.
authors.forename: E
authors.initials: E
authors.lastname: Lifschytz
authors.forename: M M
authors.initials: MM
authors.lastname: Green