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.