Excision of copia element in a revertant of the white-apricot mutation of Drosophila melanogaster leaves behind one long-terminal repeat.

The spontaneous mutation white-apricot (wa) in Drosophila melanogaster has a considerably lighter eye colour than the wild-type, and is caused by the insertion of a copia transposable element into a small intron of the white gene. We have analyzed an X-ray induced wa revertant (waR59K1), whose eye pigmentation is incompletely restored, by in situ hybridization, Southern blotting and sequencing analysis. At the site where copia had originally inserted, we found one long terminal repeat of copia, flanked by a 5 bp duplication with the same polarity as the direction of transcription of the white locus. These results suggest that the wa reversion is due to homologous recombination between the two long terminal repeats of copia.