title: Magnification in Drosophila: evidence for an inducible rDNA-specific recombination system.
abstract: An experiment is described that provides evidence for an exchange mechanism to explain the increase in ribosomal gene number that occurs during bobbed magnification. We show that bobbed and bobbed-lethal alleles do not magnify in closed X chromosomes, but that a spontaneous ring opening restores normal magnification. The results provide strong evidence that the elementary magnifying event is unequal sister chromatid exchange, and can be interpreted in the framework of an inducible rDNA-specific recombination system as the basis of ribosomal gene magnification.
authors.affiliation: Department of Microbiology, Duke University Medical Center, Durham, NC 27710.
authors.forename: D J
authors.initials: DJ
authors.lastname: Komma
authors.forename: K C
authors.initials: KC
authors.lastname: Atwood
mesh_terms: D000483:Alleles; D000818:Animals; D004275:DNA, Ribosomal / Q000235:genetics*; D004331:Drosophila melanogaster / Q000235:genetics*; D005260:Female; D005784:Gene Amplification; D008297:Male; D011995:Recombination, Genetic; D012270:Ribosomes; D012303:Ring Chromosomes; D012854:Sister Chromatid Exchange
chemical_list: D004275:DNA, Ribosomal