ChIP was performed as previously described (Thillainadesan et al. 2008) using an antibody for γH2AX. Ths library was built using the NEB ChIP-Seq Library Prep kit for the Illumina platform. Through the use of Illumina v3 chemistry, sequencing of the library was then performed on a lane of an Illumina HiSeq 2500 instrument using the multiplex paired end protocol (2x100-bases).