The zeste-white interaction: induction and genetic analysis of a novel class of zeste alleles

摘要

The recovery and analysis of a novel class of zeste mutations is described. z^op6 and z^op11 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^op mutations are strong antagonists of the z⁺ gene product. z^op6 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 z¹ 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.