With age, hematopoietic stem cells can acquire somatic mutations (indicated in blue). If these mutations confer an advantage, these mutated HSCs can expand and give rise to clonal hematopoiesis. In humans, this has been documented from 40 years and older. As demonstrated by Chin et al, in mice, mutations in the same genes implicated in clonal hematopoiesis can be detected in 2-year-old mice (see figure). Upon secondary transplant, these preexisting HSCs can expand as seen in humans, demonstrating that mice can be used to model clonal hematopoiesis in vivo.