The SPO11 protein generates programmed DNA double-strand breaks (DSBs) that initiate meiotic recombination. Endonucleolytic cleavage 3′ to the DSB sites releases SPO11 from DNA, leaving SPO11 covalently associated with an oligonucleotide. This chapter describes detection of the release product, SPO11-oligonucleotide complexes, from mouse testis lysates. The method for determining the size of SPO11-associated oligonucleotides is also provided.
