Bari-1, a new transposon-like family in Drosophila melanogaster with a unique heterochromatic organization.

We have identified a new middle repetitive DNA family in Drosophila melanogaster. This family is composed of a 1.7-kb element, called Bari-1, that shows common characteristics with many transposable elements. Bari-1 is present in a few euchromatic sites that vary in different stocks. However, it is peculiar in that most copies are homogeneously clustered with a unique location in a specific heterochromatic region close to the centromere of the second chromosome. The molecular analysis of different copies coming from the euchromatin and the heterochromatin has revealed that, independent of their location, all possess the same open reading frame. The putative protein encoded by Bari-1 shares similarity with the transposase of the Tc1 transposon of Caenorhabditis elegans. We compare the Bari-1 organization with other mobile DNA families and discuss the possibility of some functional role for the heterochromatic cluster.