Lifelong blood production is maintained by self-renewing and multi-lineage differentiating hematopoietic stem cell (HSC). Inflammation associated with infection and aging increases the division of hematopoietic stem cells and decreases its cellular function. The advanced sequencing technology has demonstrated that gradual accumulation of genetic mutations in HSCs alters clonal hematopoiesis triggering hematological disorders and leukemia. Here, we will study how inflammation is involved in the process using clonal hematopoietic tracer mice that we will newly generate.