Mitotic double-strand breaks (DSBs) are repaired by recombination with a homologous donor duplex. This process involves the exchange of single DNA strands between the broken molecule and the repair template, giving rise to regions of heteroduplex DNA (hetDNA). The creation of a defined DSB coupled with the use of a sequence-diverged repair template allows the fine-structure mapping of hetDNA through the sequencing of recombination products. A high-throughput method is described that capitalizes on the single-molecule real-time (SMRT) sequencing technology developed by PacBio. This method allows simultaneous analysis of the hetDNA contained within hundreds of recombination products.