ATAC-seq Assay for transposase-accessible chromatin sequencing (ATAC-seq) has been used extensively in a wide range of organisms to map functional elements using Tn5 transposase’s ability to enrich for open (actively regulated) chromatin regions irrespective of the unique aspects of the organism’s genome. ATAC-seq can identifyactive regulatory elements including but not limited to gene promoters, enhancer elements, and insulators. ATAC-seq operates on minimal cell input (<50K cells), is a simple assay (~2 hrs), and does not suffer from many of the issues present in other genome-wide epigenomic assays (RNA-degradation, target specific affinity reagents, etc.).