title: Rearrangements of the 5S RNA gene cluster of Drosophila melanogaster associated with the insertion of a B104 element.
abstract: The organization of the 5S RNA gene cluster of Drosophila melanogaster is different in two Oregon R stocks that have been separated for a number of years. The Oregon R Yale population contains various different arrangements of the cluster. One of these is due to the insertion of a B104 element near one end of the cluster. Other arrangements lack the B104 insertion and have instead a variety of deletions originating in the vicinity of the B104 insertion site and removing from 0 to 60% of the 5S RNA genes without affecting nearby tRNA genes. In contrast, the Oregon R Heidelberg population has no B104 element in the 5S gene cluster and no heterogeneity in the arrangement of the cluster. We propose that transposable elements inserted at a genomic locus generate heterogeneity in a population at that locus due to excision of the element with and without accompanying deletions of flanking sequences. As a consequence, a fly population would accumulate a large number of deletions scattered throughout the genome in as many loci as contain transposable elements. We show further that D. melanogaster contains a large redundancy of 5S RNA genes since the 60% deletion of the cluster shows no visible phenotype when homozygous or when heterozygous against a total deletion of the entire 5S gene cluster.
authors.affiliation: European Molecular Biology Laboratory, Postfach 10.2209, D-6900 Heidelberg, FRG.
authors.forename: C
authors.initials: C
authors.lastname: Tschudi
authors.forename: V
authors.initials: V
authors.lastname: Pirrotta
authors.forename: N
authors.initials: N
authors.lastname: Junakovic