Distribution of the retrotransposable element 412 in Drosophila species

Copy numbers of sequences homologous to the Drosophila melanogaster retrotr ansposable element 412, their distribution between the chromosome arms and the chromocenter, and whether they contain full-size copies were analyzed f or 55 species of the Drosophila genus. Element 412 insertion sites were det ected on the chromosome arms of D. melanogaster, Drosophila simulans, and a few species of the obscura group, but the chromocenter was labeled in almo st all species. The presence of element 412 sequences in the majority of sp ecies shows that this element has a long evolutionary history in Drosophili dae, although it may have recently invaded the chromosomes in some species, such as D. simulans. Differences in copy number between species may be due to population size or specific endogenous or environmental factors and may follow the worldwide invasion of the species. Putative full-length copies were detected in the chromocenters of some species with no copies on the ch romosome arms, suggesting that the chromocenter may be a shelter for such c opies and not only for deleted ones.