ATAC-seq libraries were constructed using the Nexterra kit (Illumina) and then subjected to 8 rounds of amplification with index-specific primers. The ATAC-seq libraries were quantified by both Bioanalyzer and Qubit measurements and pooled in equimolar ratios. They were sequenced on an Illumina HiSeq 4000 sequencer with paired-end 100bp reads on 6 lanes.