The hobo-related elements in the melanogaster species group.

The hobo-related sequences (hRSs) were considered as degenerate and inactive elements until recently, when one mobilizable copy was described. Using this sequence as the initial seed to search for homologous sequences in 12 available Drosophila genomes, in addition to searching for these sequences by PCR and Southern blot in nine other species, we found homologous sequences in every species of the Drosophila melanogaster species subgroup. Some evidence suggests that these non-autonomous sequences were kept mobilizable for at least 0.4 million years. Also, some very short sequences with miniature inverted-repeat transposable element (MITE) characteristics were found among these hRSs. These hRSs and their 'MITE-like' counterparts could provide a good example of the steps proposed in models that describe the MITEs origin.