Omni-ATAC-seq was performed according to Corces et al., Nature Methods 14, 959-962, 2017 with minor modifications. Prior to transposition dead cells were removed by centrifugation (800 rpm, 4 min, 4°C). The transposition reaction was with 7.5 µl Tagment DNA Enzyme 1 (TDE1) for 60 min at 37°C. Pre-amplification was with NEBNext Ultra II Q5 Master Mix and Nextera PCR Primers (5 cycles). Quantitative PCR amplification was with NEBNext Ultra II Q5 Master Mix, Nextera PCR Primer and SYBR Gold to determine the number of additional cycles. PCR amplification of additional cycles was as for pre-amplification. PCR fragments were purified with Qiagen MinElute PCR Purification Kit and library concentration and quality were determined by Agilent High Sensitive DNA Kit and Bioanalyzer, respectively.