Rescue of viability in mice homozygous for deletion of adult - and β-globin genes by expression of human embryonic ζ- and -globin. (A) Globin profile of m^−/−/hζ mice. Clarified erythrocyte lysates prepared from mice with the indicated genotypes were resolved by Triton-acid-urea gel electrophoresis and visualized by Coomassie Blue staining. The identity of each globin band is indicated to the left of the gel. (B) Globin profile of mβ^−/−/h mice. Clarified erythrocyte lysates were analyzed as described in (A). Genotypes are shown at the top, and globins identified to the left. (C) Physical appearance of m^−/−/hζ mice. Female m^−/−/hζ and control CD-1 mice are shown. (D) Physical appearance of mβ^−/−/h mice. Male mβ^−/−/h and control C57BL6 mice are shown.