Histone modifications within the β-globin locus in definitive erythroid cells from mice harboring deletions of the ϵy- and/or βh1-globin gene promoters. (A) Enrichments for H3Ac (top) and H3K4 dimethyl (bottom) at the indicated locations within the β-globin locus in E14.5 fetal liver from wild-type and Δϵy/Δβh1 Pr. mice. (B) Enrichments for H3Ac (top) and H3K4 dimethyl (bottom) at the indicated locations within the β-globin locus in E14.5 fetal liver from Δϵy Pr. and Δβh1 Pr. mice. The locus is shown to scale above the bar graphs as before, with the promoter deletions indicated by gray brackets. The more lightly shaded portions of the graphs in panels A and B represent regions in which a significant difference in histone modification levels between erythroid cells derived from wild-type and the promoter deletion mice is evident.