ATAC-seq (Assay for Transposase-Accessible Chromatin using sequencing) is a technique used in molecular biology to assess genome-wide chromatin accessibility. In 2013, the technique was first described as an alternative advanced method for MNase-seq (sequencing of micrococcal nuclease sensitive sites), FAIRE-Seq and DNase-Seq. ATAC-seq is a faster and more sensitive analysis of the epigenome than DNase-seq or MNase-seq. (Wikipedia)