FACS analysis of 2-week-old c-kit⁺/CD13⁺ (A) and c-kit⁺/CD13⁻ (B) progeny for CD13, c-kit, and Fc_ɛRI expression; or c-kit and Fc_ɛRI expression on the cell population gated by FSC and SSC to identify mast cells. Results shown are representative of 4 experiments separately performed, using either BM (n = 2) or PB (n = 2) cells.