Deletion of either or both embryonic gene promoter(s) increased transcription of β-major/minor in primitive erythroid cells. (A) Representative RT-PCR/RFLP assay of β-major/minor transcription in e10.5 ΔEy/S, Δβh1/S, and ΔEyΔβh1/S yolk sac primitive erythroid cells. Sample genotypes are marked above the gel. (B) Quantitation of β-major/minor transcription in yolk sac of promoter deletion mutants. Each pair of bars represents data from 2 litters, with a total of at least 12 embryos with error bars denoting SD. Mutations assayed and days of gestation are indicated below the graph. Wild-type ratios from e10.5 and e11.5 were close to 1 and were normalized to 1, and the mutant ratio was similarly adjusted. Wild-type ratios from e9.5 were not normalized and are represented as simple D/S ratios from each genotype. All mutant ratios are statistically different from wild-type ratios (P > .05) for e10.5 and e11.5 but not e9.5. (C) Representative RT-PCR/RFLP assay and (D) quantitation of β-major/minor transcription in ΔEy/S, Δβh1/S, and ΔEyΔβh1/S adult peripheral blood. Genotype of each sample is marked above the gel. Each pair of bars represents data from least 5 adult mice. Wild-type D/S ratios were normalized to 1.