title: Characterization of mutations that enhance position-effect variegation in Drosophila melanogaster.
abstract: Several mutants that enhance the gene inactivation associated with position-effect variegation [E(var) mutants] have been characterized. These include three ethyl methanesulfonate (EMS)-induced lesions and a second chromosome duplication. Each of the EMS mutations maps to a discrete euchromatic site on the third chromosome. One is located within the chromosomal region occupied by a cluster of Su(var) mutations. All four E(var) mutants enhance the inactivation of several different variegators and therefore they appear to influence position-effect variegation generally. However, the enhancement caused by the single site E(var) mutations is less striking than that caused by the duplication or by loss of the Y chromosome. The interaction between the E(var) mutants and selected Su(var) mutations, as well as the effects of extra Y heterochromatin on E(var) expression, have also been investigated. Based on the results of these studies, various hypothetical functions of the E(var)+ products are suggested.
authors.affiliation: Department of Zoology, University of British Columbia, Vancouver, Canada.
authors.forename: D A
authors.initials: DA
authors.lastname: Sinclair
authors.forename: V K
authors.initials: VK
authors.lastname: Lloyd
authors.forename: T A
authors.initials: TA
authors.lastname: Grigliatti
mesh_terms: D000483:Alleles; D000818:Animals; D002874:Chromosome Mapping; D004331:Drosophila melanogaster / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D005260:Female; D006570:Heterochromatin / Q000235:genetics; D008297:Male; D009154:Mutation; D010641:Phenotype; D010858:Pigmentation / Q000235:genetics; D014998:Y Chromosome
chemical_list: D006570:Heterochromatin