Chromosomal mapping of a middle-repetitive DNA sequence in a cluster of five species of Hawaiian Drosophila.

We describe the properties of a repetitive transposable element isolated from a chromosomal site close to the Adh (alcohol dehydrogenase gene) region of the Hawaiian Drosophila species, D. heteroneura. The cloned element is less than 2 kilobases in length. Although its polytene chromosome sites are constant in an individual, it shows a pattern of in situ hybridization that varies both within and between five species of the D. planitibia subgroup. These species are closely related, having diverged at various times from 0.5 to 5 million years ago. The distribution of the element appears to reflect the evolutionary relationships of the species except that the differences between D. planitibia and D. differens are ambiguous. Evidence of ragged excision of the element is found in one species.