This article describes GFP-based fluorescence in vivo assays that separately quantify homologous recombination and nonhomologous end joining in mammalian cells.
Seluanov, A., Mao, Z., Gorbunova, V. Analysis of DNA Double-strand Break (DSB) Repair in Mammalian Cells. J. Vis. Exp. (43), e2002, doi:10.3791/2002 (2010).