Cells were harvested and frozen in culture media containing FBS and 5% DMSO. Cryopreserved cells were thawed in a 37oC water bath, pelleted, washed with cold PBS. Cell pellets were resuspended in lysis buffer, pelleted, and tagmented using the enzyme and buffer provided in the Nextera Library Prep Kit (Illumina) Tagmented DNA was purified using the MinElute PCR purification kit (Qiagen), amplified with 10 cycles of PCR, and purified using Agencourt AMPure SPRI beads (Beckman Coulter)