Abstract
The deletion-fusion fragment of the Drosophila melanogaster X-chromosome deficiency Df(1)N5419 was cloned in a lambda phage vector. DNA on the genetic left side of the fusion contains sequences homologous to the roo family of transposable repetitive elements. Restriction mapping data are consistent with the right end of the roo element being situated near the breakpoint. The deficiency is of spontaneous origin, and it is possible that transposition of the roo element was involved in the deletion event.
