Cells were centrifuged and cell pallets were resuspended in 100ul of lysis buffer (TrisHCl 10mM, NaCl 10mM, MgCl2 3mM, Igepal 0.1%) and centrifuged at 500g for 25 minutes at 4ºC. Supernatant was carefully discarded and nuclei were resuspended in 50ul of reaction buffer (Tn5 transposase 2.5ul, TD buffer 22.5ul, from Nextera DNA sample preparation kit, Illumina, and 25ul H20). The reaction was performed at 37ºC for 30min and was stopped by addition of 5ul of clean up buffer (NaCl 900mM, EDTA 300mM). DNA was purified using the MiniElute purification kit (QIAGEN) following manufacturer protocol. DNA libraries were PCR amplified (Nextera DNA Sample Preparation Kit, Illumina), and size selected from200 to 800bp (BluePippin, Sage Sciences), following manufacturer ́s recommendations.