THE MARINER TRANSPOSABLE ELEMENT IN NATURAL-POPULATIONS OF DROSOPHILA-TEISSIERI

The mariner transposable elements of several natural populations of Dr osophila teissieri, a rain-forest species endemic to tropical Africa, were studied. Natural populations trapped along a transect from Zimbab we to the Ivory Coast were analyzed by Southern blotting, in situ hybr idization, cloning, and sequencing of PCR products. The Brazzaville po pulation had some full-length elements, while the remaining population s had mainly deleted elements. The main class of deleted elements lack ed a 500-bp segment. A mechanism is proposed that could generate such elements rapidly. In situ hybridizations showed that there are no Mari ner elements in pericentromeric heterochromatin. Finally, the phylogen y of the Mos1-like mariner full-length elements is consistent with ver tical transmission from the ancestor of the melanogaster subgroup.