The rare inversion with a P element at the breakpoint maintained in a natural population of Drosophila melanogaster.

We found a rare inversion which is superimposed on the In(2R) NS chromosome. It has been maintained for several years in the Raleigh, N.C., USA population and possibly for more than ten years in the southern populations of the USA. Both the breakpoint of the rare inversion and the corresponding site of the In(2R) NS chromosome have P elements and therefore, the rare inversion might be induced by P element activity in a natural population.