Mice were humanely euthanized via CO2 inhalation followed by a secondary cervical dislocation. The femurs, tibiae, pelvis, spine, humerus, and sternum were all taken and crushed to release bone marrow. After red blood cell lysis with ACK buffer, cells were magnetically enriched for cKit+ cells and then stained with Lineage. cKit, Sca-1, Flk2, CD48, and CD150  antibodies to sort on LT-HSCs (L-S+K+Flk2-CD48-CD150+) cells. Cells were combined from 2 mice for each genotype. Cells were then pelleted and then subjected to the ATAC-Seq kit from ActiveMotif with the following modification: the amount of assemlbed transposomes were scaled based on the number of cells we were able to isolate. Then the rest of the directions were followed per the manufacturer's instructions. Illumina Nexteria i7 and i5 primers were used to generate libraries and distinguish between samples. Samples were PCR amplified using Q5 polymerase for a total of 12 cycles and Solid Phase Reversible Immobilization (SPRI) beads were used for clean up. Libraries were analyzed on a tapestation and Bioanalyzer for fragment distribution and concentration respectively. Samples were sequenced on an Illumina NovaSeq with paired end reads.