Histone H3K4 dimethylation and trimethylation at B-specific genes in CD34⁺CD38^lo and CD19⁺ cells. Multipotent CD34⁺CD38^lo and B-committed CD19⁺ cells were subjected to ChIP analyses with antibodies to H3K4me2 (▭) and H3K4me3 (). Results were calculated as in Figure 1 and are means and standard deviations of at least 2 independent ChIP experiments analyzed in triplicate.