Table 3.

Active β-major transcription in orthochromatic normoblasts and nucleated RBCs as determined by primary transcript RNA FISH

	Alleles analyzed, no.	Percentage expressing alleles	Standard error
WT	152	86	2.8
ΔHS-62.5, Δ3′HS1	150	87	2.7

Fetal liver cells of WT and homozygous ΔHS-62.5, Δ3′HS1 mice were isolated, stained, fractionated, and subjected to primary transcript FISH as described.³⁹ Cells staining with TER-119, but not with antibodies to CD117 or ERY-1, representing the most mature nucleated erythroid cells, were analyzed.