ATAC-seq was performed as previously described (Buenrostro et al., 2013) with minor modifocations in the tagmentation step where we used a homemade Tn5 enzyme and assembeld the Tn5-adapter tagmentation mix ourselves. However, the adapter sequences and primers used for library amplification are the same as in the Buenrostro et al. protocol. transposed DNA was amplified with RT-qPCR monitoring to avoid oveamplification and the libraries were purified with AMPure XP beads.