Gloor, G.B., Nassif, N.A., Johnson-Schlitz, D.M., Preston, C.R., Engels, W.R. (1991). Targeted gene replacement in Drosophila via P-element-induced gap repair.  Science 253(): 1110--1117.

FBrf0055056

Research paper

Transposable elements of the P family in Drosophila are thought to transpose by a cut-and-paste process that leaves a double-strand gap. The repair of such gaps resulted in the transfer of up to several kilobase pairs of information from a homologous template sequence to the site of P element excision by a process similar to gene conversion. The template was an in vitro-modified sequence that was tested at various genomic positions. Characterization of 123 conversion tracts provided a detailed description of their length and distribution. Most events were continuous conversion tracts that overlapped the P insertion site without concomitant conversion of the template. The average conversion tract was 1379 base pairs, and the distribution of tract lengths fit a simple model of gap enlargement. The conversion events occurred at sufficiently high frequencies to form the basis of an efficient means of directed gene replacement.