ATAC-Seq uses the Tn5 transposome to detect nucleosome-free regions of the genome. The method is commonly used, and optimized protocols are available for tissues, such as blood (Fast-ATAC)1, neurons2, biobank specimens3, and single cells (scATAC-seq4 and single-cell ATAC-seq5).
In this method, gDNA is incubated with Tn5 transposomes, which fragments it and adds adapters simultaneously, in open chromatin regions. Deep sequencing of the purified regions provides base-pair resolution of nucleosome-free regions in the genome.