library_construction_protocol: After isolation of nuclei, transposition was performed using the kit (Illumina, #FC-121-1030). DNA was then amplified using NEBNext High Fidelity 2X PCR Master Mix (New England Biolabs, #M0541S) for 5 cycles. DNA quantity was then measured using a Viia 7 Real-Time PCR System (Thermo Fisher Scientific) and the number of cycles required to achieve 1/3 of maximal SYBR Green fluorescence was determined and libraries were amplified accordingly. TruSeq adaptors (universal: Ad1_noMX and barcoded: Ad2.1-Ad2.24) were used according to the Buenrostro protocol. Libraries were purified using MiniElute PCR Purification Kit (Qiagen, #28006) followed by double sided Agencourt AMPure XP bead purification (Beckman Coulter, #A63881) to remove primer dimers and large DNA fragments. Libraries were analyzed on a 2100 Bioanalyzer (Agilent Technologies) and High Sensitivity DNA Kit (Agilent Technologies, #5067-4626). Libraries were sequenced by Genewiz on an Illumina HiSeq 4000 by 2x75 bp paired end sequencing.