Arhgef2^−/− mice exhibit mildly altered hematopoietic parameters. (A) Non-Mendelian ratios observed from heterozygous Arhgef2^fl/– crosses across 205 born pups (top); relative percentage and absolute number of fetal liver (FL) HSCs (Lin^–CD150⁺CD48^–CD11b⁺) are decreased in Arhgef2^−/− embryos (bottom). (B) Decreased circulating platelets in Arhgef2^−/− mice (n = 4 mice per age group). (C) Higher myeloid:B lymphoid ratios and (D) fewer Lin^– cell populations. (E) Less restricted (left), lymphoid progenitors in Arhgef2^−/− bone marrow (BM) (middle), and relative increase in myeloid progenitors within Lin^– compartment of Arhgef2^−/− bone marrow (bottom). (F) LSK HSCs (left) and LSK+SLAM long-term HSCs (LT-HSCs) (right) are not statistically different in Arhgef2^−/− mice. (C-F) Total of n = 7 mice per group. Error bars represent SEM. *P < .05; **P < .01. n.s., not significant.