The cell pellet was re-suspended in a transposase-containing reaction mixture complete with 0.05% digitonin prior to tagmentation at 37oC with 1000 rpm agitation for 30 minutes. Next, transposed DNA was purified with a Qiagen PCR MinElute kit (Qiagen 28004). According to Fast-ATAC protocol, with Illumina Nextera kit transposase and custom Illumina adapters.