P element-mediated duplications of genomic regions in Drosophila melanogaster

Abstract

Previously we have described highly unstable yellow mutations induced by chimeric elements that consist of genomic sequences originating from different regions of the X chromosome flanked by identical copies of an internally deleted 1.2 kb P element. To study further the origin and the mechanism of formation of chimeric mobile elements, we analyzed complex y-sc mutations, induced by inversions between P elements located in the neighboring yellow and scute loci. The breakpoints of the inversions are flanked by two P elements in head-to-head orientation on one side and by one P element on the other side. Such an arrangement of P elements leads to frequent duplication into the site between the two P element copies located in head-to-head orientation of the yellow sequences adjacent to the single P element. The duplicated yellow sequences either partly replace the sequence of one of the P elements or are inserted between the conserved head-to-head oriented P elements. In some cases two copies of the yellow sequence are duplicated between the P elements in inverted tail-to-tail orientation. The structure of the P elements at the place of duplication and of the P element- yellow junction suggests that the described duplications, which form chimeric mobile elements, are generated through the previously proposed synthesis-dependent strand annealing mechanism.

Transposition of Regulatory Elements by P-Element-Mediated Rearrangements in Drosophila melanogaster

“…Hereafter, the Pfry 1 D2-3g99B construction is referred to as D2-3. The highly unstable mutations in the yellow locus used in this work have been described (Georgiev et al 1997;Golovnin et al 2002). All other mutant alleles and chromosomes as well as balancer chromosomes have been described in Lindsley and Zimm (1992).…”

“…The mutations were large in number for all the genes, with a full spectrum of phenotypes. Some highly unstable mutations in the yellow gene were molecularly characterized (Georgiev et al 1997;Golovnin et al 2002). These mutations were generated by insertion of a chimeric element at ÿ69 bp relative to the yellow transcription start site.…”

Properties of re-arranged P elements in Drosophila melanogaster

“…Golovnin et al (2002) found numerous insertions and inversions in a region containing three P elements. Comparable events have also been analysed in other eukaryotes, including Ac in maize (Zhang and Peterson, 1999) and a Tc1-mariner element, impala, in the fungus Fusarium (Hua- Van et al, 2002).…”