Telomere repeats within the neo-Y-chromosome of Drosophila miranda

The clone Dmir1098, isolated from a genomic lambda library of Drosophila miranda labels exclusively the tips of the giant chromosomes in the highly polytenized nuclei of the female larval salivary glands. However, the in situ hybridizations to male metaphase plates, using the same probe, reveal a massive labeling block within the neo-Y-chromosome in addition to the labeling blocks at both chromosome ends. From the comparison with the Y chromosome labeling pattern of D. pseudoobscura, a sibling species to D. miranda, an end-to-end fusion mechanism involving the telomere repeats would be the most straightforward explanation for the karyotype change in D. miranda.