Majority of MEPs are in the CD38^mid fraction. (A) Sorting strategy used to evaluate MPL⁺ and MPL⁻ cells within CD38 negative, low, mid, and high subsets of Lin⁻CD34⁺ MPB cells followed by exclusion of FLT3⁺ and CD45RA⁺ cells. (B) Dual Mk/E and (C) methylcellulose colony assay results. Results are presented as average + SD from 3 independent experiments.