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

Previously we described highly unstable mutations in the yellow locus, induced by the chimeric element and consisting of sequences from a distally located 1A unique genomic region, flanked by identical copies of an internally deleted 1.2-kb P element. Here we show that a sequence, which is part of the yellow 1A region, can be transmitted to the AS-C by successive inversion and reinversion generated by yellow- and AS-C-located P elements. The chimeric element contains a regulatory element from the 1A region that specifically blocks yellow wing and body enhancers and simultaneously stimulates yellow expression in bristles. These results suggest that P-element-generated chimeric elements may play a certain role in rapid changes of regulatory regions of genes during evolution.