E Pluribus Unum ("Out of Many, One"): CRISPR Modeling of Myeloid Expansion.

In this issue of Cell Stem Cell, Tothova et al. (2017) demonstrate a promising way to model the complex genetics of clonal hematopoiesis and myeloid disorders using CRISPR-Cas9 genome editing in human hematopoietic stem and progenitor cells. Their approach opens the door to genotype-specific pharmacologic testing.