Order of sequences 5'-3': an Act5C promoter, a truncated fragment of the DsRed2 coding region, an RS(I-SceI) site, a second truncated DsRed2 coding region fragment that begins with a 147bp duplication of the end of the first DsRed2 fragment, and the Drs 3' control region. The Act5C promoter drives expression of the first truncated DsRed2 coding region fragment, which produces a non-functional product. Designed to study the relative usage of alternative pathways of double-strand break repair in D. melanogaster.