title: Histone gene deficiencies and position--effect variegation in Drosophila.
mesh_terms: D000483:Alleles; D000818:Animals; D002872:Chromosome Deletion; D004331:Drosophila melanogaster / Q000235:genetics*; D005796:Genes; D008040:Genetic Linkage; D006570:Heterochromatin; D006579:Heterozygote; D006657:Histones / Q000235:genetics*
chemical_list: D006570:Heterochromatin; D006657:Histones