library_construction_protocol: OmniATAC was performed on either fresh or cryopreserved cells using 50,000 nuclei per sample, using Illumina Tagment DNA enzyme and Buffer (Illumina, 20034197). qPCR side-reactions were performed to determine optimal PCR cycle number for each sample. Libraries were assessed using the TapeStation D1000 Assay and sequenced on the Illumina NextSeq 500 (75 bp paired end reads, approximately 30-40 million paired-end reads per sample).