Transposition of P{lacW} gammaCop057302 into the germline of Drosophila melanogaster correlates with retaining of the original insertion

We performed a genetic and molecular screening in Drosophila melanogaster in order to investigate the mobilization pattern of P{lacW} gammaCop057302 , a lethal transposon insertion located in 5'UTR of gammaCop gene from 100C chromosomal region. New mutant lines, with modified levels of eye pigmentation, were obtained consequent to transposition in both male and female germline. A total of 153 founder individuals were preliminary screened, 68 of them descending from dysgenic males and 85 from dysgenic females. From a total of 114 reinsertion events occurring within the third chromosome, 98 were associated with an apparent conservation of the original insertion. A consistent tendency towards retaining of the original insertion has been also noticed in an older collection of 40 mutant lines harboring transposition events that also affect the third chromosome. Our data show a strong correlation between transposition and the retaining of P{lacW} gammaCop057302 original insertion, a phenomenon that may unravel functional aspects of the P element's mobilization pattern. Conservation of the starting element may also represent an useful marker in genetic screenings aiming to detect local reinsertions of the P element.